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WELLSITE PROCEDURES AND OPERATIONS

Version 3.0 March 2001

David Hawker Karen Vogt Allan Robinson (sections 11.8 and 11.9)

Corporate MissionTo be a worldwide leader in providing drilling and geological monitoring solutions to the oil and gas industry, by utilizing innovative technologies and delivering exceptional customer service.

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

CONTENTS1 RIGS AND THEIR EQUIPMENT ...................................................................................................................... 9 1.1 ROTARY DRILLING RIGS.................................................................................................................................... 9 1.1.1 Land Rigs .................................................................................................................................................. 9 1.1.2 Offshore drilling vessels............................................................................................................................ 9 Barges ............................................................................................................................................................. 9 Jack-Up Rigs ................................................................................................................................................... 9 Semi-Submersible Rigs ................................................................................................................................. 10 Drillships....................................................................................................................................................... 10 Platforms ....................................................................................................................................................... 10 1.1.3 Land Rig Examples ................................................................................................................................. 11 1.1.4 Jack Up Example .................................................................................................................................... 13 1.1.5 Semi-Submersible Example..................................................................................................................... 14 2 ROTARY RIG COMPONENTS ....................................................................................................................... 15 2.1 THE HOISTING SYSTEM ................................................................................................................................... 16 2.1.1 Providing Rotation to the Drillstring and Bit ......................................................................................... 18 Kelly and Swivel ........................................................................................................................................... 18 Top Drive Units ............................................................................................................................................ 19 2.1.2 Lifting Equipment.................................................................................................................................... 20 Bails and Elevators........................................................................................................................................ 20 Slips............................................................................................................................................................... 21 Tongs............................................................................................................................................................. 21 Power Tongs and Pipe Spinners.................................................................................................................... 21 Chain Wrench................................................................................................................................................ 21 2.2 THE CIRCULATING SYSTEM ............................................................................................................................ 23 2.2.1 Solids Control Equipment ....................................................................................................................... 25 2.3 DRILL BIT AND DRILLSTRING .......................................................................................................................... 29 2.3.1 Drag Bits................................................................................................................................................. 29 2.3.2 Roller Tri-Cone Bits................................................................................................................................ 29 Bit Terminology ............................................................................................................................................ 30 IADC Bit Classification ................................................................................................................................ 30 Cone Action .................................................................................................................................................. 31 Bearing Types ............................................................................................................................................... 31 Teeth ............................................................................................................................................................. 31 Operating requirements ................................................................................................................................. 32 2.3.3 Diamond and Polycrystalline Diamond Compact (PDC) bits ................................................................ 33 2.3.4 Grading Of Bits....................................................................................................................................... 34 The IADC bit grading system........................................................................................................................ 34 2.3.6 The Drillstring......................................................................................................................................... 35 2.3.7 Drillpipe.................................................................................................................................................. 35 2.3.8 Drill Collars............................................................................................................................................ 36 2.3.9 The Bottom Hole Assembly (BHA) .......................................................................................................... 37 Stabilizers...................................................................................................................................................... 37 Reamers......................................................................................................................................................... 37 Hole Opener .................................................................................................................................................. 38 Cross Over Sub ............................................................................................................................................. 38 Jars ................................................................................................................................................................ 38 Shock Sub.................................................................................................................................................... 39 2.4 BLOW OUT PREVENTION SYSTEM ................................................................................................................... 40 2.4.1 BOP Stack ............................................................................................................................................... 40 2.4.2 Closing the well....................................................................................................................................... 41 DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 1

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

Annular Preventer ......................................................................................................................................... 41 Ram Type Preventers .................................................................................................................................... 41 2.4.3 Closing the preventers ............................................................................................................................ 42 Accumulators ................................................................................................................................................ 43 Control Panel................................................................................................................................................. 43 Positioning of the rams.................................................................................................................................. 44 Kill Lines....................................................................................................................................................... 44 The Diverter .................................................................................................................................................. 45 2.4.4 Inside Blowout Preventers ...................................................................................................................... 46 Surface Shut Off Valves................................................................................................................................ 46 Downhole Check Valves ............................................................................................................................... 46 2.4.5 Rotating BOPs ........................................................................................................................................ 46 3 THE DRILLING FLUID.................................................................................................................................... 48 3.1 PURPOSES OF THE DRILLING FLUID ................................................................................................................. 48 3.1.1 Cool and Lubricate the Bit and Drillstring............................................................................................. 48 3.1.2 Bottom Hole Cleaning............................................................................................................................. 48 3.1.3 Control Subsurface Pressures................................................................................................................. 48 3.1.4 Line the Hole with Filter Cake................................................................................................................ 49 3.1.5 Help Support the Weight of the Drillstring ............................................................................................. 49 3.1.6 Cuttings Removal and Release................................................................................................................ 49 3.1.7 Transmit Hydraulic Horsepower to the Bit............................................................................................. 49 3.1.8 Hole Stability .......................................................................................................................................... 50 3.1.9 Formation Protection and Evaluation .................................................................................................... 50 3.2 COMMON DRILLING FLUIDS ............................................................................................................................ 51 3.2.1 Air/Gas.................................................................................................................................................... 51 3.2.2 Foam or Aerated Fluids.......................................................................................................................... 51 3.2.3 Water-Base Muds.................................................................................................................................... 52 3.2.4 Oil-Emulsion Muds ................................................................................................................................. 52 3.2.5 Oil-Base Muds ........................................................................................................................................ 53 3.3 BASIC MUD RHEOLOGY .................................................................................................................................. 54 3.3.1 Mud Density ............................................................................................................................................ 54 3.3.2 Mud Viscosity.......................................................................................................................................... 54 3.3.3 Gel Strength ............................................................................................................................................ 55 3.3.4 High vs. Low Viscosity and Gel Strength................................................................................................ 55 3.3.5 Filtrate/Fluid Loss .................................................................................................................................. 55 3.3.6 Filter Cake .............................................................................................................................................. 56 3.3.7 Mud pH Level.......................................................................................................................................... 56 3.3.8 Mud Salinity ............................................................................................................................................ 56 4 DRILLING A WELL.......................................................................................................................................... 57 4.1 WELL BALANCE .............................................................................................................................................. 57 4.1.1 Underbalance versus Overbalance ......................................................................................................... 57 4.2 THE WELL BORE............................................................................................................................................. 59 4.2.1 Starting Point .......................................................................................................................................... 59 4.2.2 Surface Hole............................................................................................................................................ 59 4.2.3 Intermediate Hole ................................................................................................................................... 60 4.2.4 Total Depth ............................................................................................................................................. 61 4.3 DRILLING AND MAKING HOLE......................................................................................................................... 63 4.3.1 Pipe Tally ................................................................................................................................................ 63 4.3.2 Drill Breaks and Flow Checks ................................................................................................................ 63 4.3.3 Reaming .................................................................................................................................................. 64 4.3.4 Circulating .............................................................................................................................................. 64 4.4 CORING ........................................................................................................................................................... 66 4.4.1 Purpose ................................................................................................................................................... 66 DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 2

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

4.4.2 Coring Methods ...................................................................................................................................... 66 4.4.3 Core Barrel Assembly ............................................................................................................................. 67 4.4.4 Retrieval and Handling Operations ........................................................................................................ 67 4.5 TRIPPING ......................................................................................................................................................... 69 4.5.1 Trip Speed ............................................................................................................................................... 69 4.5.2 Pulling Out of Hole................................................................................................................................. 69 4.5.3 Swabbing................................................................................................................................................. 70 4.5.4 Running In Hole...................................................................................................................................... 71 4.5.5 Monitoring Displacements ...................................................................................................................... 72 4.5.6 Hook Load............................................................................................................................................... 72 4.5.7 Strapping and Rabbiting the Pipe........................................................................................................... 73 4.6 ELECTRICAL LOGGING .................................................................................................................................... 74 4.6.1 Formation Evaluation ............................................................................................................................. 74 4.6.2 Hole Condition........................................................................................................................................ 75 4.7 CASING AND CEMENTING ................................................................................................................................ 77 4.7.1 Purpose ................................................................................................................................................... 77 4.7.2 Types of Casing....................................................................................................................................... 77 4.7.3 Surface Equipment .................................................................................................................................. 78 4.7.4 Subsurface Equipment ............................................................................................................................ 78 4.7.5 Preparing to Run Casing ........................................................................................................................ 79 4.7.6 Running Casing....................................................................................................................................... 80 4.7.7 Cementing Operation.............................................................................................................................. 81 4.7.8 Other Applications .................................................................................................................................. 82 4.8 PRESSURE TESTS ............................................................................................................................................ 83 4.8.1 Leak-Off and Formation Integrity Tests.................................................................................................. 83 4.8.2 Repeat Formation Testing....................................................................................................................... 84 4.8.3 Drill Stem Testing ................................................................................................................................... 85 Performing a Drill Stem Test ........................................................................................................................ 86 5 DEVIATION CONTROL................................................................................................................................... 87 5.1 COMMON CAUSES OF DEVIATION ................................................................................................................... 87 5.1.1 Interbedded Lithology / Drillability ........................................................................................................ 87 5.1.2 Formation Dip ........................................................................................................................................ 87 5.1.3 Faults ...................................................................................................................................................... 88 5.1.4 Poor Drilling Practices........................................................................................................................... 88 5.2 PROBLEMS ASSOCIATED WITH DEVIATION ...................................................................................................... 89 5.2.1 Doglegs and Keyseats ............................................................................................................................. 89 5.2.2 Ledges ..................................................................................................................................................... 90 5.2.3 Stuck Pipe ............................................................................................................................................... 90 5.2.4 Increased Torque/Drag and Drill Pipe Fatigue ..................................................................................... 90 5.2.5 Casing and Cementing ............................................................................................................................ 91 5.3 PREVENTION OF DEVIATION ............................................................................................................................ 92 5.3.1 Pendulum Effect ...................................................................................................................................... 92 5.3.2 Pendulum Assembly ................................................................................................................................ 92 5.3.3 Packed-Hole Assembly............................................................................................................................ 93 5.3.4 Packed Pendulum Assembly.................................................................................................................... 94 5.3.5 Stabilizers and Reamers.......................................................................................................................... 94 5.3.6 Drilling Procedures ................................................................................................................................ 95 6 DIRECTIONAL AND HORIZONTAL DRILLING ....................................................................................... 96 6.1 REASONS FOR DIRECTIONAL DRILLING ........................................................................................................... 96 6.2 SURVEYS/CALCULATIONS ............................................................................................................................... 98 6.2.1 Survey Methods....................................................................................................................................... 98 Single-Shot Surveys ...................................................................................................................................... 98 Multi-Shot Surveys........................................................................................................................................ 98 DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 3

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

Gyroscopic Surveys....................................................................................................................................... 98 Measurement While Drilling (MWD) ........................................................................................................... 98 6.2.2 Survey Measurements ............................................................................................................................. 99 6.2.3 Survey Calculation Methods ................................................................................................................... 99 Radius of Curvature ...................................................................................................................................... 99 Minimum Curvature .................................................................................................................................... 100 6.2.4 Directional Drilling Terminology ......................................................................................................... 101 6.3 DRILLING TECHNIQUES ................................................................................................................................. 103 6.3.1 Well Profiles.......................................................................................................................................... 103 Shallow Deflection Profile .......................................................................................................................... 103 S-Curve Profile............................................................................................................................................ 103 Deep Deflection Profile............................................................................................................................... 103 6.3.2 Drilling Stages ...................................................................................................................................... 104 6.3.3 Whipstocks, Motors and Techniques..................................................................................................... 105 Whipstocks.................................................................................................................................................. 105 Downhole Motors and Bent Subs................................................................................................................ 105 Rotating and Sliding.................................................................................................................................... 106 Jetting.......................................................................................................................................................... 106 6.4 HORIZONTAL DRILLING ................................................................................................................................. 107 6.4.1 Classification ........................................................................................................................................ 107 6.4.2 Horizontal Drilling Considerations ...................................................................................................... 108 Radius Effects ............................................................................................................................................. 108 Reversed Drill String Design ...................................................................................................................... 108 Drill Pipe Fatigue ........................................................................................................................................ 109 Hole Cleaning.............................................................................................................................................. 109 Use of Top Drives ....................................................................................................................................... 110 Casing and Cementing................................................................................................................................. 110 Formation Considerations ........................................................................................................................... 110 Formation Evaluation.................................................................................................................................. 111 Gas Behaviour/Well Control....................................................................................................................... 111 7 DRILLING PROBLEMS ................................................................................................................................. 112 7.1 FORMATION PROBLEMS AND HOLE STABILITY.............................................................................................. 112 7.1.1 Fractures............................................................................................................................................... 112 Associated Problems ................................................................................................................................... 112 Drilling Fractured Formations..................................................................................................................... 113 7.1.2 Shales .................................................................................................................................................... 113 Reactive Shales ........................................................................................................................................... 113 Overpressured Shales .................................................................................................................................. 114 7.1.3 Surface Formations............................................................................................................................... 115 7.1.4 Salt Sections .......................................................................................................................................... 115 7.1.5 Coal Beds .............................................................................................................................................. 115 7.1.6 Anhydrite/Gypsum Formations ............................................................................................................. 116 7.2 LOST CIRCULATION....................................................................................................................................... 117 7.2.1 Occurrences .......................................................................................................................................... 117 7.2.2 Detection ............................................................................................................................................... 117 7.2.3 Problems ............................................................................................................................................... 118 7.2.4 Prevention ............................................................................................................................................. 118 7.2.5 Remedies ............................................................................................................................................... 119 7.3 KICKS AND BLOWOUTS ................................................................................................................................. 120 7.3.1 Causes Of Kicks .................................................................................................................................... 120 7.3.2 Kick Warning Signs............................................................................................................................... 121 7.3.3 Indications Of Kicks While Drilling...................................................................................................... 122 7.3.4 Indicators While Tripping ..................................................................................................................... 123 7.3.5 Flowchecks............................................................................................................................................ 124 DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 4

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

7.4 STUCK PIPE ................................................................................................................................................... 125 7.4.1 Hole Pack-Off or Bridge ....................................................................................................................... 125 Sloughing or Caving of Reactive or Pressured Shales ................................................................................ 125 Fractured or Unconsolidated Formations .................................................................................................... 126 Settling Cuttings and Cuttings Beds ............................................................................................................ 126 Cement or Junk ........................................................................................................................................... 126 Mobile Salt.................................................................................................................................................. 126 7.4.2 Differential Sticking .............................................................................................................................. 127 7.4.3 Wellbore Geometry ............................................................................................................................... 128 7.4.4 Rotary Drilling Jars .............................................................................................................................. 129 Hydraulic Jars ............................................................................................................................................. 129 Mechanical Jars........................................................................................................................................... 130 Jar Accelerator ............................................................................................................................................ 130 7.4.5 Fish Cause and Indication ................................................................................................................. 130 7.4.6 Fishing Equipment ................................................................................................................................ 131 Junk Basket ................................................................................................................................................. 131 Fishing Magnet............................................................................................................................................ 131 Impression Block ........................................................................................................................................ 132 Milling Tools............................................................................................................................................... 132 Overshots .................................................................................................................................................... 132 Spears.......................................................................................................................................................... 132 Washover Pipe ............................................................................................................................................ 133 Free-Point Indicator .................................................................................................................................... 133 Jars and Accelerators................................................................................................................................... 133 Safety Joints and Bumper Subs ................................................................................................................... 133 7.5 DRILL STRING VIBRATIONS ........................................................................................................................... 134 7.5.1 Torsional Vibration............................................................................................................................... 134 7.5.2 Axial Vibration...................................................................................................................................... 135 7.5.3 Lateral Vibration .................................................................................................................................. 137 7.6 WASHOUTS ................................................................................................................................................... 139 7.6.1 Drill String Washouts............................................................................................................................ 139 7.6.2 Hole Washouts ...................................................................................................................................... 139 8 UNDERBALANCED DRILLING ................................................................................................................... 141 8.1 BENEFITS AND LIMITATIONS OF UNDERBALANCED DRILLING ....................................................................... 142 8.2 UNDERBALANCED DRILLING FLUIDS............................................................................................................. 143 8.2.1 Gas & Air Drilling ................................................................................................................................ 143 Advantages and Disadvantages ................................................................................................................... 143 Equipment ................................................................................................................................................... 143 Drilling Operations...................................................................................................................................... 144 Drilling Problems ........................................................................................................................................ 144 8.2.2 Mist ....................................................................................................................................................... 145 8.2.3 Foam ..................................................................................................................................................... 145 8.2.4 Aerated Mud.......................................................................................................................................... 146 8.2.5 Mud ....................................................................................................................................................... 146 8.3 EQUIPMENT AND PROCEDURES ..................................................................................................................... 148 8.3.1 Rotating Heads...................................................................................................................................... 148 8.3.2 Closed Circulating and Separating Systems ......................................................................................... 148 8.3.3 Blooie Line and Sample Catcher .......................................................................................................... 149 8.3.4 Gas Measurement ................................................................................................................................. 149 8.4 COILED TUBING UNITS .................................................................................................................................. 151 8.4.1 Components........................................................................................................................................... 151 8.4.2 Drilling Applications............................................................................................................................. 152 8.4.3 Advantages and Disadvantages ............................................................................................................ 152

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

9 ROCKS AND RESERVOIRS .......................................................................................................................... 154 9.1 INTRODUCTORY PETROLOGY ........................................................................................................................ 154 9.1.1 Igneous.................................................................................................................................................. 154 9.1.2 Metamorphic ......................................................................................................................................... 154 9.1.3 Sedimentary........................................................................................................................................... 154 Sediment Classification............................................................................................................................... 155 Compaction and Cementation ..................................................................................................................... 156 Clastic Rock Types ..................................................................................................................................... 156 Chemical and Organic Rock Types ............................................................................................................. 157 9.2 PETROLEUM GEOLOGY ................................................................................................................................. 158 9.2.1 Petroleum Generation........................................................................................................................... 158 9.2.2 Maturation of Petroleum....................................................................................................................... 159 9.2.3 Petroleum Migration............................................................................................................................. 160 9.2.4 Primary Migration ................................................................................................................................ 160 9.2.5 Secondary Migration ............................................................................................................................ 161 9.2.6 Hydrocarbon Traps............................................................................................................................... 162 Stratigraphic Traps...................................................................................................................................... 162 Structural Traps........................................................................................................................................... 163 9.3 PETROLEUM COMPOSITION ........................................................................................................................... 165 9.3.1 Saturated Hydrocarbons or Alkanes..................................................................................................... 165 Paraffin........................................................................................................................................................ 165 Naphthenes.................................................................................................................................................. 167 9.3.2 Unsaturated Hydrocarbons or Aromatics............................................................................................. 167 9.3.3 API Gravity Classification .................................................................................................................... 168 9.4 RESERVOIR CHARACTERISTICS ..................................................................................................................... 169 9.4.1 Porosity ................................................................................................................................................. 169 Sandstones................................................................................................................................................... 169 Limestones .................................................................................................................................................. 169 9.4.2 Permeability.......................................................................................................................................... 170 9.4.3 Water Saturation ................................................................................................................................... 170 9.4.4 Reservoir Zones, Contacts and Terminology ........................................................................................ 171 10 MUD LOGGING - INSTRUMENTATION AND INTERPRETATION ................................................... 172 10.1 DEPTH AND RATE OF PENETRATION ............................................................................................................ 172 10.1.1 The Geolograph .................................................................................................................................. 172 10.1.2 Depth Wheel........................................................................................................................................ 173 10.1.3 Crown Sheave ..................................................................................................................................... 173 10.1.4 Drawworks Sensor .............................................................................................................................. 174 10.1.5 Heave Compensation .......................................................................................................................... 174 10.1.6 Rate of Penetration ............................................................................................................................. 177 Bit Selection................................................................................................................................................ 177 Rotary Speed (RPM) ................................................................................................................................... 177 Weight on Bit (WOB or FOB) .................................................................................................................... 177 Differential Pressure.................................................................................................................................... 178 Hydraulics and Bottom Hole Cleaning........................................................................................................ 178 Bit Wear ...................................................................................................................................................... 179 Lithology..................................................................................................................................................... 179 Depth........................................................................................................................................................... 179 Formation Pressure...................................................................................................................................... 179 10.1.7 Drilling Breaks.................................................................................................................................... 179 10.1.8 Controlled Drilling ............................................................................................................................. 181 10.2 HOOKLOAD AND WEIGHT ON BIT ................................................................................................................ 183 10.2.1 Load or Pancake Cell ......................................................................................................................... 183 10.2.2 Strain Gauge ....................................................................................................................................... 184 DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 6

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

10.2.3 Weight on Bit....................................................................................................................................... 184 10.2.4 Hookload, Drag and Overpull ........................................................................................................... 185 10.3 ROTARY SPEED AND ROTARY TORQUE ....................................................................................................... 187 10.3.1 Rotary Speed ....................................................................................................................................... 187 10.3.2 Rotary Torque ..................................................................................................................................... 187 10.3.3 Formation evaluation and fracture identification............................................................................... 189 10.3.4 Sticking Pipe ....................................................................................................................................... 189 10.3.5 Torsional Vibrations ........................................................................................................................... 190 10.4 PUMP OR STANDPIPE PRESSURE .................................................................................................................. 191 10.5 ANNULAR OR CASING PRESSURE ................................................................................................................ 194 10.6 PUMP RATE AND OUTPUT ........................................................................................................................... 195 10.6.1 Pump Output Calculation ................................................................................................................... 196 10.6.2 Lag Calculations................................................................................................................................. 197 10.7 FLOWRATE AND PIT LEVELS ....................................................................................................................... 201 11 MUDLOGGING PROCEDURES ................................................................................................................. 203 11.1 CUTTINGS DESCRIPTIONS ............................................................................................................................ 203 11.1.1 Rock Type and Classification.............................................................................................................. 203 11.1.2 Color ................................................................................................................................................... 203 11.1.3 Texture ................................................................................................................................................ 204 Carbonate Rocks ......................................................................................................................................... 204 Siliceous Rocks ........................................................................................................................................... 204 Argillaceous Rocks ..................................................................................................................................... 205 Carbonaceous Rocks ................................................................................................................................... 205 11.1.4 Cement and Matrix.............................................................................................................................. 205 11.1.5 Hardness ............................................................................................................................................. 205 11.1.6 Fossils and Accessory Minerals.......................................................................................................... 205 11.1.7 Sedimentary Structures ....................................................................................................................... 206 11.1.8 Porosity ............................................................................................................................................... 206 Siliceous Rocks ........................................................................................................................................... 206 Carbonate Rocks ......................................................................................................................................... 206 11.1.9 Chemical Tests .................................................................................................................................... 206 HCl Effervescence....................................................................................................................................... 206 HCl Oil Reaction......................................................................................................................................... 206 Swelling....................................................................................................................................................... 207 Sulphate Test Gypsum and Anhydrite...................................................................................................... 207 Chloride Test............................................................................................................................................... 208 Alizarin Red ................................................................................................................................................ 208 Cement Test ................................................................................................................................................ 208 11.2 OIL SHOWS ................................................................................................................................................. 209 11.2.1 Odour .................................................................................................................................................. 209 11.2.2 Oil Staining and Bleeding ................................................................................................................... 209 11.2.3 Fluorescence ....................................................................................................................................... 209 Sample Preparation ..................................................................................................................................... 210 Contaminants............................................................................................................................................... 210 Colour and Brightness................................................................................................................................. 211 Fluorescence Distribution ........................................................................................................................... 211 Solvent Cut.................................................................................................................................................. 212 Residue........................................................................................................................................................ 213 Sampling the mud........................................................................................................................................ 213 11.2.4 Quantitative Fluorescence TechniqueTM ............................................................................................. 213 11.3 CUTTINGS BULK DENSITY ........................................................................................................................... 216 11.4 SHALE DENSITY .......................................................................................................................................... 218 11.5 SHALE FACTOR ........................................................................................................................................... 220 11.6 CALCIMETRY .............................................................................................................................................. 221 DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 7

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

11.7 ENHANCED HOLE MONITORING .................................................................................................................. 223 11.7.1 Consequences of poor stability / poor hole cleaning .......................................................................... 223 11.7.2 Problems of Measuring Actual Cuttings Volume ................................................................................ 223 Are all the cuttings being collected? ........................................................................................................... 224 What about mud volume?............................................................................................................................ 224 How accurate is the unit of measurement for a period of an hour? ............................................................. 224 11.7.3 Volume of Vessel ................................................................................................................................. 224 11.7.4 Measurement of Cuttings/Hour........................................................................................................... 225 11.7.5 Correction to Total Volume ................................................................................................................ 225 11.7.6 Theoretical Cuttings Volume............................................................................................................... 227 11.7.7 Actual/Theoretical Cuttings Volume Ratio ......................................................................................... 228 11.7.8 Recording, Evaluating and Reporting ................................................................................................ 228 11.8 HIGH RESOLUTION TRIP MONITORING ........................................................................................................ 232 11.8.1 Theory and Benefits ............................................................................................................................ 232 11.8.2 Procedure............................................................................................................................................ 232 Theoretical Hookload.................................................................................................................................. 233 System and Data Preparation ...................................................................................................................... 233 11.8.3 Interpretation ...................................................................................................................................... 233 11.8.4 Benefits to the Operator...................................................................................................................... 236 11.9 DST PROCEDURES ...................................................................................................................................... 237 11.9.1 Water Cushion..................................................................................................................................... 237 11.9.2 Test String Components ...................................................................................................................... 237 11.9.3 Testing Procedures ............................................................................................................................. 241

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

1 RIGS AND THEIR EQUIPMENT1.1 Rotary Drilling RigsIn the early days of petroleum exploration and production, wells were drilled with cable tool rigs. The technique used was percussive drilling where a hardened bit, suspended on a cable, was repeatedly dropped onto the bottom of the hole. The constant pounding would break up the formation, deepening the hole in the process. The drawbacks to the cable tool rig were limited depth capabilities, very slow drilling rates and no way to control subsurface formation pressures. Modern drilling uses a rotary drilling method providing faster drilling rates, much greater depth capabilities, offshore drilling, and the safe control of subsurface pressures. 1.1.1 Land Rigs Land rigs are typically designed around a cantilever mast principle, providing easy transportation and quick assembly. The mast, or derrick, is transported to the drill site in sections, assembled on the ground, then raised to a vertical position by using the rigs hoisting system (drawworks). Blow out preventers are positioned directly beneath the rig floor, connecting the floor to the well head. This allows drilling fluid to be circulated and pipe to be lifted in and out of the well.

1.1.2 Offshore drilling vessels Drilling offshore obviously requires a completely self-contained vessel, not only in terms of drilling requirements, but also in terms of accommodation for personnel. Situated in remote, hostile locations, they are much more costly to operate and require more sophisticated safety measures since water separates the wellhead from the actual rig. There are different types of offshore rigs and their use principally depends on the depth of water that they are required to operate in. Temporary installations (that can move from location to location) used for exploratory drilling, can either be supported by the seabed or they can be floating and anchored in positioned. Permanent installations, or platforms, are required for production wells.Barges

These are small, flat-bottomed vessels that can only be used in very shallow waters such as deltas, swamps, lagoons and shallow lakes.Jack-Up Rigs

These are mobile vessel suitable for drilling in shallow seawater depths. They consist of a fixed hull or platform, which is supported on by a number of legs, typically 3, that stand on the seafloor. To move a jack-up rig, the legs can be raised so that the rig floats on its hull enabling it to be towed into position by barges. This makes the vessel very top heavy and unstable during towing, so that calm waters and slow towing speeds are essential to avoid capsize. Once in the required position, the legsDATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 9

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

can be lowered to the seabed creating a very stable structure unaffected by wave motion. The blow out preventers are mounted underneath the rig floor, so that a large conductor pipe, driven into the seafloor, is required to connect the well to the rig and allow drilling fluid to be circulated.Semi-Submersible Rigs

Semi-subs are floating rigs that are suitable for drilling in deeper waters than jack-ups. The deck is supported by a number of legs or columns. Subsea, these columns are supported by pontoons which can be solitary or connected. Both pontoons and columns are utilized to ballast and stabilize the rig. This substructure sits below the sea surface, avoiding the worst, surface turbulence of the water. This makes them more stable than drillships and therefore more suited to drilling in rough seas. The pontoons are fitted with thrusters for position adjustment or self- propulsion, but they are generally moved into position by sea going tugs, with the thrusters being used to assist in the final positioning of the rig. Once correctly positioned, the semi-submersible is anchored in place, although in deeper waters the thrusters may be used to maintain position by way of an automated location monitor. Unlike the jack-up, blowout preventers are located on the seabed, mounted on conductor pipe that has been set into the seafloor. Positioning of the BOPs is very tricky and achieved with the assistance of underwater cameras or remotely operated vehicles (ROVs). This allows the well to be left secure should the rig be forced to abandon the location. A large flexible, telescopic steel pipe, called the marine riser, connects the BOPs to the rig, enabling drilling fluid to be circulated and the drillstring to be guided into the well.Drillships

Drillships are capable of drilling in deeper water. They are generally self propelled and therefore easily transported to the drilling location. They are extremely mobile, but generally less stable than semi-submersibles and therefore not able to drill in rougher seas. A drillship can be anchored, or position maintained by automated thruster systems. The drillship has exactly the same subsea equipment as a semi-submersible, with the BOPs mounted on the seabed. To compensate for movement of the drillship (also semi-submersibles), the marine riser includes a telescopic joint to allow for vertical movement. A ball joint at the seafloor allows for horizontal motion. The length of the riser is often the limiting factor in deep water drilling, before it becomes subjected to too much bending and stress.Platforms

Platforms are permanently fixed structures installed where mobility is not required. This is typically when multiple wells are going to be drilled to develop and produce a field. Platforms can be of two designs, piled or gravity structures. A piled platform consists of a steel jacket, which is pinned to the seabed and supports the deck structure. This type of platform is stable in very bad weather conditions, but is not very mobile. They are usually constructed in separate sections that can be individually towed to position and constructed in place. Gravity type platforms are constructed from concrete, steel or a combination of both. They have a cellular base, providing both ballast and storage, with vertical columns supporting the deck structure. They are normally constructed in their entirety, then towed to the location and ballasted into position.

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

1.1.3 Land Rig Examples

..before the mast has been raised into position

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

1.1.4 Jack Up Example

3 Supporting legs are most typical. Note, here, that drilling has not yet started, since there is no conductor pipe in place.

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

1.1.5 Semi-Submersible Example

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

2 ROTARY RIG COMPONENTSThe modern rotary drilling rig, whatever the type, consists of 5 principle components: (1) Drill Bit and Drillstring (2) Fluid Circulating System (3) Hoisting System (4) Power System (5) Blowout Prevention System The term rotary comes from the physical movement of the drillstring and bit, applying a rotary cutting action to the rock at the bottom of the hole. Rotation can be provided at surface or by motors positioned in the drillstring downhole. The drillstring (1) consists of hollow steel pipe allowing drilling fluid to be transported into the hole. The pipe will typically be a combination of standard drillpipe, thicker, heavier drillpipe and larger diameter, heavy drill collars immediately above the bit. This is all supported from the derrick with vertical movement (in and out of the hole) provided by the drawworks, crown block and traveling block (3). Rotation of the drillstring, at surface, is applied in one of two ways, either by a rotary table, bushings and kelly or by a top drive unit. The drilling fluid, commonly referred to as drilling mud, is stored in mud tanks or pits. From here, the mud can be pumped, via the standpipe, to the kelly swivel where it can enter the kelly and subsequently the drillpipe. The mud can then pass all the way to the bit, before returning to surface through the annulus (the space between the wall of the borehole and the drillstring). On return to surface, the mud is passed through several pieces of equipment to remove the drilled rock chips or cuttings, before completing the cycle and returning to the mud tanks (2). Formations in the shallower part of the wellbore are usually protected by large diameter steel tubing, or casing, which is cemented into place. The annulus that the mud now passes through on its way back to surface is now the space between the inside of the casing and the outside of the drillstring. Attached to the top of the casing is the blowout preventer stack (5), a series of valves and seals that can be used to close off the annulus or wellbore in order to control large subsurface pressures. All of the equipment described above is operated by a central power system (4), which will also supply the general power required for electrical lighting, service company equipment etc. Typically, this power source is by way of a central diesel-electric power plant.

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

2.1 The Hoisting SystemFast sheave Crown block

Drill line or Fast line Travelling block

Dead line

Hook

Dead line anchor Drawworks drum

The hoisting system supported by the derrick

The complete hoisting system has several basic functions: Supporting the weight of the drillstring, possibly up to several hundred tonnes. Lifting the drillstring in and out of the hole. Maintaining the force, or weight, applied to the bit during drilling.

The derrick supports the weight of the drillstring at all times, whether the drillstring is suspended from the crown block or supported temporarily in the rotary table. The size and strength of the derrick is the limiting factor to the weight of drillpipe that can be supported and therefore the depth that the rig is capable of drilling to. The height of the derrick will determine the length of the pipe sections that can housed when the drillstring has to be pulled from the hole. During this operation, the pipe will normally be broken down into double or triple stands (2 or 3 individual lengths, or joints, of pipe). During the drilling operation, the kelly and drillstring are supported from the traveling block by way of the traveling hook. This is connected to the drawworks by way of a simple pulley system. A steel cable, the drilling line, is spooled on a large reel at the drawworks where it can be drawn in, or let out, depending on whether an upward or downward motion of the traveling block is required. From the drawworks, the drilling line passes up to a stationary set of pulleys, called the crown block, situated at the top of the derrick. Here, the cable is repeatedly passed between a series of wheels, or sheaves, and theDATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 16

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

traveling block suspended in the derrick, so that the traveling block will be suspended by a number of lines, typically 8 to 12. The drilling line is then passed from the crown block to an anchor where the cable is securely clamped.

Fast line up to crown block

Drawworks Drum

This length of drilling line is referred to as the dead line, and the deadline anchor is typically located to one side of rig floor. From the deadline anchor, the drilling line passes to a storage reel, to one side of the rig, where extra drilling line is stored. The drilling line is commonly referred to as the fast line for the length running from the drawworks to the crown block. This is because the first sheave that it is spooled around is generally larger than the others and known as the fast sheave. The usage of the drilling line, or wear, is recorded in terms of the load moved over a given distance. For example, 1 ton-mile means that the line has moved a 1 ton weight a distance of 1 mile. Similarly, a measurement of 1kN-km means that the line has moved 1000 newtons a distance of 1 kilometre. This record allows the drilling crew to determine when the drilling line needs to be replaced by a new length of cable. The slip and cut procedure requires the traveling block to be lowered to the drill floor so that there is no load on the drilling line. The line is released at the dead line anchor so that new line can be fed, or slipped, through. The line is tensioned by feeding it through the pulley system and pullingDATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 17

Travelling block

Hook

Kelly hose

Elevators Bushings Kelly

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

the old line out from the drawworks. This old line can be removed, or cut, and the new length of cable tensioned and anchored once more at the dead line anchor. This procedure allows for even wear on the drilling line as it is used. The drawworks have a heavy duty braking system allowing for the speed to be controlled, or resisted, when moving the pipe into the hole. During the drilling operation, the drawworks also allows for control, or adjustment, of the proportion of the string weight that is supported by the derrick and that which is supported by the bottom of the hole. This equates to the weight, or force, that is applied to the bit, and thus can be adjusted according to the hardness of the formation and the weight required in order to produce failure of the formation, and allow penetration, or deepening of the hole to proceed.

2.1.1 Providing Rotation to the Drillstring and BitKelly and Swivel

The kelly is a hollow length of steel, normally around 12 or 13m in length, either square or hexagonal, through which drilling fluid can enter the drillpipe. The top of the drillstring is connected to the kelly by a kelly sub (or saver sub). This sub, being cheaper to replace than the kelly, saves wear on the connecting threads of the kelly, which passes through a rotary kelly bushing mounted and locked into master bushings that are set into the rotary table.

kelly

kelly bushings

Free vertical movement of the kelly is possible through the bushing, allowing upward and rotary table downward movement of the drillstring. Rollers within the bushing facilitate this movement and, drillpipe joint in mousehole again, minimize the wear on the kelly. The shape of the kelly (commonly 4 or 6 sided) fits exactly into the bushing so that, if the bushing rotates, the kelly rotates. Since the bushing is locked into the rotary table, rotation of the table (either electrically or mechanically) will rotate the bushing and therefore the kelly and drillpipe. Vertical movement is still possible even if the kelly is rotating. When the kelly is lifted from the hole to expose the drillpipe, the kelly bushings are lifted along with the kelly. Between the kelly and the hook is an assembly known as the swivel. This supports the kelly but does not rotate as the kelly rotates. This prevents the hook and traveling block from rotating and twisting the drilling line as the string is rotated. The swivel is also the point at which the drilling fluid enters the drillstring, through an attachment known as a gooseneck connected to the kelly hose carrying the drilling fluid. A safety valve is located at the top of the kelly. This kelly cock can be manually closed in the event of the well flowing due to high, subsurface, formation pressure. This prevents back pressure from entering, and perhaps damaging, the kelly swivel.DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 18

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

Top Drive Units

On more recent rigs, the rotary drive and swivel are combined into a single top drive unit, which may be electrically or hydraulically operated. The drillstring now connects directly into the top drive unit where rotation is applied and where drilling fluid enters the string through a similar swivel and gooseneck assembly. Since rotation is now applied directly to the top of the drillstring, there is no requirement for a kelly and rotary bushing. The advantage of a top drive unit over the conventional kelly system is primarily one of time and cost. With the kelly, as drilling progresses, only single lengths, or joints, can be added to the drillstring. This connection process requires the kelly being broken off from the drillstring, picking up and attaching the new joint of pipe to the kelly, then re-attaching the new pipe and kelly back to the drillstring. With a top drive unit, this operation is not only made much simpler by the fact that pipe is connected directly to the unit, but it also enables a stand of drillpipe (equivalent to 3 single joints of pipe) to be picked up and added to the drillstring at any one time. A complete stand of drillpipe can therefore be drilled continuously, so that only one connection is required for every three that would be required with a kelly. Overall time required to make connections is therefore much less for rigs possessing top drive units. This means a big saving in cost, especially for large land rigs or offshore rigs where the daily cost of hiring the rig is much more expensive.

Travelling Block

Top Drive

Elevators Drillpipe ingress

Another important advantage of the top drive unit is during tripping operations, when the drillstring is being lifted in or out of the hole. The conventional kelly is not used when tripping pipe. It is set aside on the rig floor in what is called the rat-hole. Bails and elevators are then used to lift the drillstring. If the pipe was to become stuck during the trip, circulation of drilling fluid may be required to free the pipe. In order to achieve this, the kelly would have to be picked up from the rat-hole and attached to the drillstring, a process that may take as long as 5 or 10 minutes during which time, the sticking of the pipe may become worse. With a top drive unit, elevators are again used to lift the pipe, but these areDATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 19

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

suspended beneath the top drive unit. It is therefore a very quick procedure to attach the top drive unit to the drillstring so that circulation of drilling fluid and rotation of the pipe is possible almost immediately. In most circumstances, this minimizes the potential problem and reduces the time that may be required to resolve it. 2.1.2 Lifting Equipment The procedures of tripping, lifting the pipe in and out of the hole, and making connections, adding new lengths of drillpipe to the drillstring in order to drill deeper, have already been introduced. Handling of the pipe during these operations requires the use of specialized pieces of equipment. To pull a stand of drillpipe from the hole, the elevators are clamped around the pipe. When the blocks are raised, the elevators rest beneath the larger diameter tool joint so that the pipe can be lifted. When the stand is completely above the rotary table, slips will be held around the pipe as it is slowly lowered. The slips will wedge firmly in the rotary table, clasping the pipe. The total weight of the string is now supported by the rotary table.

bails

elevators

slips

The stand above the table can now be removed from the string and set aside. Firstly, the tool joint connection is broken with two sets of tongs, one positioned beneath the tool joint holding the pipe steady, the second positioned above the tool joint. This is connected by a chain, which is pulled in at the cathead, breaking the connection. The stand is quickly unscrewed by using a pipe spinner, so that it is free and hanging from the elevators. The stand is racked to one side monkey board of the derrick and held in position by placing the and fingers top of the stand in a rack known as fingers. This operation is performed by the derrickman racked drillpipe who works up in the derrick on a platform known as the monkey board.Bails and Elevators

These are used to lift the pipe into position or remove it when the connection has been broken. The elevators are simply clamps that are placed and closed around the stem of the pipe. As the elevators are lifted, they will move up the pipe until they come against the wider tool joint so that the pipe can be lifted. The elevators are suspended from the traveling block by links or bails, so that vertical movement is applied from the drawworks. Elevators are ofDATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001 20

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

specific sizes and designs to accommodate pipe of different diameter, casing joints and drill collars.Slips

While connections are being made or broken, the drillstring has to be suspended and supported in the rotary table to prevent it from fallen down the hole. This is achieved by using slips, tapered or wedged shaped dies held together in a frame with handles. These are placed around the stem of the pipe and lowered, along with the pipe, into the master bushings where they become set, fully supporting the weight of the drillstring in the rotary table.Tongs

Slips

These are used to tighten or loosen the connections between sections of pipe. These wrenches are suspended on cables from the derrick and attached to the cathead, on the drawworks, by a chain through which tension can be applied. Two tongs are used, being placed on either side of the connection or joint. The lower tong will hold the drillstring in place below the joint and the upper tong, by pulling on the chain, will loosen or break the connection or in the opposite direction, tighten or make the connection. When making the connection, a gauge on the chain allows the correct amount of torque to be applied.Power Tongs and Pipe Spinners

pipe spinner

These are pneumatically powered wrenches enabling rapid spinning of the pipe during the making or breaking of connections. Tongs will be used to apply final torque when making the connection and to initially loosen the joint when breaking the connection.Chain Wrench tongs

chain to cathead

Breaking tool joint to make a connection

If pneumatic wrenches are not available, spinning of the pipe has to be done manually by way of a chain wrench. Chain is wrapped around the pipe, clasped and gripped by the wrench. Spinning of the pipe is done by physically

walking around the pipe while it is gripped and held by the wrench. When pipe has to be added in order to drill further, it is picked up from the pipe deck to one side of the rig. A winch is used to pull the pipe up so that is resting vertically against the v-door, a ramp that joins the pipe deck to the rig floor. The blocks can then be lowered and the joint of pipe picked up in the elevators (different elevators are used to pick up collars or casing tubular). Once picked up, the joint of

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

pipe is lowered into the mousehole (a hole drilled into the surface sediments and lined with tubular) where it is ready for use when the next connection is to be made.

rig floor

v-doors pipe deck

casing joints

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

2.2 The Circulating SystemWe have already seen how the drilling fluid, commonly called mud, enters the drillstring through the kelly or top drive unit. There are many ways in which the mud aids the drilling process and, in fact, is a vital component to the successful drilling of a well. The most important functions are: To cool and lubricate the drill bit and drillstring in order to minimize wear, prolong their life and reduce costs. To remove the drilled rock fragments, or cuttings from the hole. This not only keeps the annulus clear but also allows examination at surface for formation evaluation. To balance high fluid pressures that may be present in some formations and minimizing the potential of kicks or blowouts. The safety of the rigs personnel and of the rig itself is of paramount importance in any drilling operation. To stabilize the wellbore and formations that have already been drilled.

Types of drilling mud and its function will be discussed in more detail in section 4.

DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

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DATALOG WELLSITE OPERATIONS MANUAL, Version 3.0, issued March 2001

Creating a drilling mud is almost like cooking, with many ingredients or additives going into the system, each having a particular function to perform. The mud is built and stored in mud tanks or pits. Different names are given to individual pits depending on their specific function. Typically, they may be called: Premix Pit Suction Pit Where additional chemicals are added and mixed into the mud system. The pit where mud is taken by the rig pumps to begin its journey to the drillstring. This is the live or active pit, lined up to the actual wellbore. Or Settling Pit. Additional mud volume, generally not part of the active system. This is the tank situated directly beneath the shale shakers. A sand trap is normally an integral part of the shaker pit. Its purpose is to allow as much fine material, sand and silt, to settle out from the mud system and be removed. A smaller tank, used to monitor small mud displacements. Situations that require this include tripping the drillstring out of the hole and monitoring a well kick. A tank used to make up small volumes of special mud that may be required for specific operations during the drilling of a well. The number of the pits required will depend on the size and the depth of the well being drilled, and thus on the volume of mud required to fill that hole. Typi

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WELLSITE PROCEDURES AND OPERATIONS Version 3.0 March 2001 David Hawker Karen Vogt Allan Robinson (sections 11.8 and 11.9) Corporate Mission To be a worldwide leader in providing drilling and geological monitoring solutions to the oil and gas industry, by utilizing innovative technologies and delivering exceptional customer service.
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