1 | Summer Training Report, Oil India Limited, Jodhpur A PROJECT REPORT ON “OIL AND GAS EXPLORATION, EQUIPMENTS AND PRODUCTION ACTIVITIES” RAJASTHAN PROJECT JODHPUR UNDER THE GUIDANCE OF Shri. A. N. SARMAH (Head Production, Rajasthan Project) In partial fulfillment of Summer Internship During 1 st June, 2011 to 30 th June, 2011 SUBMITTED BY: Shri.Himanshu Singh Panwar B.Tech (3 rd year Mechanical Engineering) JODHPUR NATIONAL UNIVERSITY, JODHPUR
Transcript
1 | Summer Training Report, Oil India Limited, Jodhpur
A PROJECT REPORT ON
“OIL AND GAS EXPLORATION, EQUIPMENTS AND PRODUCTION ACTIVITIES”
RAJASTHAN PROJECT JODHPUR
UNDER THE GUIDANCE OF
Shri. A. N. SARMAH (Head Production, Rajasthan Project)
In partial fulfillment of Summer Internship
During 1st June, 2011 to 30th June, 2011
SUBMITTED BY:
Shri.Himanshu Singh Panwar B.Tech (3rd year Mechanical Engineering)
JODHPUR NATIONAL UNIVERSITY, JODHPUR
2 | Summer Training Report, Oil India Limited, Jodhpur
Acknowledgement
With all our due regards we would like thank and express our gratitude to our Training Co-ordinator, Shri. Mukesh Hansda, Sr. Reservoir Engineer for his valuable guidance, supervision and regular suggestions throughout the period of this Training. We acknowledge his valuable suggestions and moral boosting, without which this work would only have been a dream. We would like to thank Shri. P. Borkakoty, Chief Manager, administration J.K Borgohain, General Manager, Geoscience Department, for his constant motivation and support and also Shri. N.K. Venugopal, Chief Production Engineer for his valuable suggestions during the course of internship. We would also like to express our sincere thanks to Shri. D.S. Reddy, Production Engineer, Shri. A.G.S Rao, Production Engineer, Shri. S. Deb, Technical Services and Shri. B. Rabha, Instrumentation for their valuable guidance and support. At last, we thank all those who directly or indirectly contributed in the completion of this work. Their help and co-operation will not be forgotten.
Himanshu Singh Panwar Date: 6th July 2011
3 | Summer Training Report, Oil India Limited, Jodhpur
Content
1. Company Profile
2. Geophysical Methods of Oil & Gas Exploration
3. Geological Model of Rajasthan
4. Visit to Drilling site of phulasara -1 well
5. Introduction of drilling and rig components.
6. Mud Logging Unit
7. Visit to TVC and DND GPC
8. Problems and hurdles (including gas quality)
9. Conclusion
4 | Summer Training Report, Oil India Limited, Jodhpur
Company Profile
Introduction:
Oil India ltd is a premier National oil company, engaged in the business of Exploration, Production and Transportation of crude oil and natural gas. Oil India Ltd is a Schedule “A” company and has been awarded a “NAVRATNA” status under the Ministry of Petroleum and Natural Gas, Government of India. OIL is Asia’s oldest and one of the biggest oil exploration and production company. OIL's presence is currently in nine nations of world. In India its operations, both on-shore and off-shore spreads across the country. OIL’s strategy is to establish commercial reserves from strategic positions in high potential exploration plays in order to create and deliver shareholder value.
OIL’s expertise is in six major sectors viz. Exploration, Drilling & Workover, Production,
Reservoir Management, Pipeline and Research & Development. Company is into strategic alliance with many major companies for its various in-country and overseas operations. The Company has been consistently showing excellent financial performance over the years and has been able to build up a strong base.
OIL has over 1 lakh sq km of PEL/ML areas for its exploration and production activities,
most of it in the Indian North East, which accounts for its entire crude oil production and majority of gas production. Rajasthan is the other producing area of OIL, contributing 10 per cent of its total gas production.
Additionally, OIL’s exploration activities are spread over onshore areas of Ganga Valley
and Mahanadi. OIL also has participating interest in NELP exploration blocks in Mahanadi Offshore, Mumbai Deepwater, Krishna Godavari Deepwater, etc. as well as various overseas projects in Libya, Gabon, Iran, Nigeria and Sudan. Portfolio:
Before the introduction of NELP in 2001, Government of India used to nominate the
blocks for exploration and exploitation of hydrocarbon to ONGC and OIL. OIL major operational area is in North-East mainly in the state of Assam. It also has its major presence in western India in the state of Rajasthan. OIL contributes about 10% in India’s crude oil and natural gas production.
OIL acquired varied participating interests in a total of 33 blocks up to the end of
NELP-VII bidding round. Out of these, 18 are onshore and the rest 15 are offshore blocks. OIL is the operator in 13 onshore blocks and 1offshore block. Work is in progress in all these blocks as per the committed Minimum Work Program (MWP).
5 | Summer Training Report, Oil India Limited, Jodhpur
Geophysical Methods for Oil and Gas Exploration
Stages in development of an oil & gas field: • Exploration
– Seismic – Reserves booking and well proposal – Reserves and recovery estimate
• Appraisal – Reservoir testing – Consolidate geological understanding/ models – Test fluid contacts and substantiate reserves
• Early Development Stage – Primary oil/ gas production. – Test production. – Scope for further development
• Late Development Stage – Optimize recovery – Maintain/ improve reservoir performance
The Job of a Geophysicist: – Initially use gravity and magnetic survey and later seismic surveys – First 2 are regional in scale, less costly than seismic and are used to identify
potentially oil-bearing sedimentary basins – Create an image of the subsurface deposits and their deformations, to help
geologists identify traps. – In coordination with the geologist they interpret the image to extrapolate the
geometry of the trap.
Gravity Survey:
Measures gravity, to give some idea of the nature and depth of strata depending on their density.
Magnetic Survey:
Generally performed from the air
Measures variations in the magnetic field. This gives an idea of the depth distribution of crystalline terrains that have NO chance of containing any oil.
Seismic Surveys:
Measures the travel time of sound waves generated by a “shock” applied to the ground or sea
Essential to discovering oil and gas fields
More costly than gravity and magnetic surveys.
6 | Summer Training Report, Oil India Limited, Jodhpur
Seismic survey diagram
Geological model of Rajasthan The Jaisalmer basin is a part of westerly dipping eastern limb of lower and middle Indus basin DSand existed as essentially passive margin basin on the edge of Indian plate. A number of significant tectonic events effecting evolution of the basin, mostly related to successive stages in the break-up of Gondwanaland took place throughout the Mesozoic. The initial stage in the break-up of Gondwanaland was marked by rifting of Indian plate from the eastern margin of Africa during the Permian and Mesozoic. The stratigraphy of the basin at this time reflects the break-up, with coarse clastic sedimentation having taken place during the Permian. Stratigraphy of Jaisalmer Basin:
AGE FORMATION HORIZON TOPS (m) (Wireline
Log)
THICKNESS (m)
LITHOLOGICAL DESCRIPTION
Pliocene ALLUVIUM-SHUMAR
Surface – 532 m 532 It consisting of mainly sand with arenaceous limestone.
Middle Eocene
BANDAH 532 m – 718 m 186 It comprises gray to greenish gray, argillaceous limestone with streaks of clay.
Lower Eocene
KHUIALA 718 m – 1004 m 286 Upper part of this formation is dominated by limestone and lower part is dominated by shaly/ sandy limestone with laminas of sandstones and clays.
Paleocene SANU 1004 m – 1049 m 45 It consists predominantly of Sandstone, Clay and limestone. Glauconitic present.
Upper Cretaceous
PARH FORMATION
1049 m – 1402 m 353 It consists of Marlstone and Shale, Pyrite and Siderite is present in traces.
7 | Summer Training Report, Oil India Limited, Jodhpur
Lower to Upper Cretaceous
GORU FORMATION
1402 m – 1963 m 561 It consists predominantly of Marlstones, Shale, Sandstone, Dolostone, and Black Carbonaceous matter. Pyrite and Siderite is present in traces.
Lower Cretaceous
PARIWAR FORMATION
1963 m – 2130 m 167+ It consists predominantly of Sandstone, Shale and Black carbonaceous matter. Pyrite is present in traces.
Bikaner Nagaur Formation Stratigraphy of Bikaner-Nagur Basin
Age Formation Thickness (m) Lithology
Recent-Pliestocene Alluvium 70-95 Fine to Medium grained sand
Eocene-Paleocene Palana and Marh Equivalent
20-10 Clayey limestone and dark grey claystone
Cretaceous Parh Equivalent 30-35 Dark grey claystone and sandstone
Jurassic Lathi Equivalent 290-380 Red claystone and ferruginous sandstone with minor coal
Triassic Bap & Bandhaura Equivalent
58-86 Red, yellow and grey claystone with siltstone with conglomerate Permocarboniferous
Late Cambrian
Upper Carbonate Group
250-600 Laminated Dolostone and limestone with red claystone interbeds and occasional marl
Nagaur Group 150-190 Mottled claystone with siltsone, finegrained sandstone and minor Dolostone
Early Cambrian
Hanseran Evaporite Group
140-150 Mottled siltstone, claystone, anhydrite and salt
Bilara Group 50-55 Calcareous Dolostone
Jodhpur Sandstone
25-30 Coarse to fine grained sandstone with siltstone and claystone
Precambrian Malani Suits Volcano clastic with basalts and rhyolite flows
8 | Summer Training Report, Oil India Limited, Jodhpur
Major Discoveries of Oil India Limited at Rajasthan Project:
Tanot 1988 Gas
Dandewala 1989 Gas
Baghewala 1991 Heavy Oil
Bagitibba 1994 Gas
DND 17 2008 Gas
Gas Fields:
Area No of wells drilled
Average Depth
1. Dandewala 21 wells drilled 2100 m
2. Tanot 12 wells drilled 2200 m
3. Bagitibba 3 wells drilled 2200 m
Current Production Rate of Gas : Approximately 0.6 MMSCMD Gas is transported through 65 Km GAIL pipeline to RRVUNL (Rajasthan Rajya Vidyut Utpadan Nigam Limited) Ramgarh. Customer of gas: RRVUNL(Rajasthan Rajya Vidyut Utapadan Limited), Ramgarh Production capacity of RRVUNL : 110 MW
9 | Summer Training Report, Oil India Limited, Jodhpur
Visit to Drilling site Phulasara -1 well
Depth Data Drilling Policy
Region: Bikaner-Nagur Basin (Rajasthan) Block: RJ-ONN-2004/2 (NELP VI) Well Name: Phulasara-1 (LOC. RBAK) Well Type: Exploratory Vertical Total Depth: 1500 m Target Formations: Jodhpur, Bilara, Nagaur & Upper Carbonate formations Dry hole cost: USD 1,991,993 (Rs 8.9 crore) Completion cost: USD 71327 (Rs 0.32 crore) Planned Spud date: 22nd April 2010 Drilling Days: 45 days Testing Days: 15 days Total Days: 60 days Technical Basement: Malani Volcanics & Volcano clastics
10 | Summer Training Report, Oil India Limited, Jodhpur
Schematic Well Diagram of Phulasara-1 well
11 | Summer Training Report, Oil India Limited, Jodhpur
Introduction to Drilling Rigs and Major Rig Equipment
1. Crown Block and Water Table 2. Catline Boom and Hoist Line 3. Drilling Line 4. Monkeyboard 5. Traveling Block 6. Top Drive 7. Mast 8. Drill Pipe 9. Doghouse 10. Blowout Preventer 11. Water Tank 12. Electric Cable Tray 13. Engine Generator Sets 14. Fuel Tanks 15. Electric Control House 16. Mud Pump 17. Bulk Mud Components Storage 18. Mud Pits 19. Reserve Pits 20. Mud Gas Separator 21. Shale Shaker 22. Choke Manifold 23. Pipe Ramp 24. Pipe Racks 25. Accumulator 26. Annulus 27. Brake Bands 28. Casing Head 29. Cathead 30. Catwalk 31. Cellar 32. Conductor Pipe 33. Degasser 34. Desander 35. Desilter 36. Drawworks 37. Drill Bit 38. Drill Collar 39. Drillers Console 40. Elevators 41. Hoisting Line 42. Hook 43. Kelly
13 | Summer Training Report, Oil India Limited, Jodhpur
2.
Catline Boom and Hoist Line
A structural framework erected near the top of the derrick for lifting material.*
3.
Drilling Line
A wire rope hoisting line, reeved on sheaves of the crown block and traveling block (in effect a block and tackle). Its primary purpose is to hoist or lower drill pipe or casing from or into a well. Also, a wire rope used to support the drilling tools.*
14 | Summer Training Report, Oil India Limited, Jodhpur
4.
Monkeyboard
The derrickman's working platform. Double board, tribble board, fourable board; a monkey board located at a height in the derrick or mast equal to two, three, or four lengths of pipe respectively.*
5.
Traveling Block
An arrangement of pulleys or sheaves through which drilling cable is reeved, which moves up or down in the derrick or mast.*
15 | Summer Training Report, Oil India Limited, Jodhpur
6. Top Drive
The top drive rotates the drill string end bit without the use of a kelly and rotary table. The top drive is operated from a control console on the rig floor.*
7.
Mast
A portable derrick capable of being erected as a unit, as distinguished from a standard derrick, which cannot be raised to a working position as a unit.*
16 | Summer Training Report, Oil India Limited, Jodhpur
8. Drill Pipe
The heavy seamless tubing used to rotate the bit and circulate the drilling fluid. Joints of pipe 30 feet long are coupled together with tool joints.*
9. Doghouse
A small enclosure on the rig floor used as an office for the driller or as a storehouse for small objects. Also, any small building used as an office or for storage.*
10. Blowout Preventer
One or more valves installed at the wellhead to prevent the escape of pressure either in the annular space between the casing and the drill pipe or in open hole (for example, hole with no drill pipe) during drilling or completion operations. See annular blowout preventer and ram blowout preventer.*
17 | Summer Training Report, Oil India Limited, Jodhpur
11. Water Tank
Is used to store water that is used for mud mixing, cementing, and rig cleaning.*
12. Electric Cable Tray
Supports the heavy electrical cables that feed the power from the control panel to the rig motors.*
13.
Engine Generator Sets
A diesel, Liquefied Petroleum Gas (LPG), natural gas, or gasoline engine, along with a mechanical transmission and generator for producing power for the drilling rig. Newer rigs use electric generators to power electric motors on the other parts of the rig.*
18 | Summer Training Report, Oil India Limited, Jodhpur
14. Fuel Tanks
Fuel storage tanks for the power generating system.*
15.
Electric Control House
On diesel electric rigs, powerful diesel engines drive large electric generators. The generators produce electricity that flows through cables to electric switches and control equipment enclosed in a control cabinet or panel. Electricity is fed to electric motors via the panel.*
16. Mud Pump
A large reciprocating pump used to circulate the mud (drilling fluid) on a drilling rig.*
19 | Summer Training Report, Oil India Limited, Jodhpur
17. Bulk Mud Components Storage
Hopper type tanks for storage of drilling fluid components.*
18.
Mud Pits
A series of open tanks, usually made of steel plates, through which the drilling mud is cycled to allow sand and sediments to settle out. Additives are mixed with the mud in the pit, and the fluid is temporarily stored there before being pumped back into the well. Mud pit compartments are also called shaker pits, settling pits, and suction pits, depending on their main purpose.*
19.
Reserve Pits
A mud pit in which a supply of drilling fluid has been stored. Also, a waste pit, usually an excavated, earthen-walled pit. It may be lined with plastic to prevent soil contamination.*
20 | Summer Training Report, Oil India Limited, Jodhpur
20. Mud Gas Separator
A device that removes gas from the mud coming out of a well when a kick is being circulated out.*
21. Shale Shaker
A series of trays with sieves or screens that vibrate to remove cuttings from circulating fluid in rotary drilling operations. The size of the openings in the sieve is selected to match the size of the solids in the drilling fluid and the anticipated size of cuttings. Also called a shaker.*
22. Choke Manifold
The arrangement of piping and special valves, called chokes, through which drilling mud is circulated when the blowout preventers are closed to control the pressures encountered during a kick.*
21 | Summer Training Report, Oil India Limited, Jodhpur
23. Pipe Ramp
An angled ramp for dragging drill pipe up to the drilling platform or bringing pipe down off the drill platform.*
24. Pipe Racks
A horizontal support for tubular goods.*
25. Accumulator
The storage device for nitrogen pressurized hydraulic fluid, which is used in operating the blowout preventers.*
22 | Summer Training Report, Oil India Limited, Jodhpur
26. Annulus
The space around a pipe in a well bore, the outer wall of which may be the wall of either the bore hole or the casing; sometimes termed the annular space.*
27.
Brake Bands
The braking device on the drawworks to stop a load being lifted.*
28. Casing Head
A heavy, flanged steel fitting connected to the first string of casing. It provides a housing for slips and packing assemblies, allows suspension of intermediate and production strings of casing, and supplies the means for the annulus to be sealed off. Also called a spool.*
23 | Summer Training Report, Oil India Limited, Jodhpur
29. Cathead
A spool-shaped attachment on a winch around which rope for hoisting and pulling is wound.*
30. Catwalk
The ramp at the side of the drilling rig where pipe is laid to be lifted to the derrick floor by the catline or by an air hoist.*
31. Cellar
A pit in the ground to provide additional height between the rig floor and the well head to accommodate the installation of blowout preventers, ratholes, mouseholes, and so forth. It also collects drainage water and other fluids for disposal.*
24 | Summer Training Report, Oil India Limited, Jodhpur
32. Conductor Pipe
The largest diameter casing and the topmost length of casing. It is relatively short and encases the topmost string of casing.*
33. Degasser
The equipment used to remove unwanted gas from a liquid, especially from drilling fluid.*
34. Desander
A centrifugal device for removing sand from drilling fluid to prevent abrasion of the pumps. It may be operated mechanically or by a fast-moving stream of fluid inside a special cone-shaped vessel, in which case it is sometimes called a hydrocyclone.*
25 | Summer Training Report, Oil India Limited, Jodhpur
35. Desilter
A centrifugal device, similar to a desander, used to remove very fine particles, or silt, from drilling fluid. This keeps the amount of solids in the fluid to the lowest possible level.*
36. Drawworks
The hoisting mechanism on a drilling rig. It is essentially a large winch that spools off or takes in the drilling line and thus raises or lowers the drill stem and bit.*
37. Drill Bit
The cutting or boring element used in drilling oil and gas wells. Most bits used in rotary drilling are roller-cone bits. The bit consists of the cutting elements and the circulating element. The circulating element permits the passage of drilling fluid and uses the hydraulic force of the fluid stream to improve drilling rates.*
26 | Summer Training Report, Oil India Limited, Jodhpur
38. Drill Collar
A heavy, thick-walled tube, usually steel, used between the drill pipe and the bit in the drill stem. It is used to put weight on the bit so that the bit can drill.*
39. Drillers Console
The control panel, located on the platform, where the driller controls drilling operations.*
40.
Elevators
A set of clamps that grips a stand, or column, of casing, tubing, drill pipe, or sucker rods, so the stand can be raised or lowered into the hole.*
27 | Summer Training Report, Oil India Limited, Jodhpur
41. Hoisting Line
A wire rope used in hoisting operations. Must conform to the API standards for its intended uses.*
42.
Hook
A large, hook-shaped device from which the elevator bails or the swivel is suspended. It is designed to carry maximum loads ranging from 100 to 650 tons and turns on bearings in its supporting housing.*
28 | Summer Training Report, Oil India Limited, Jodhpur
43. Kelly
The heavy square or hexagonal steel member suspended from the swivel through the rotary table. It is connected to the topmost joint of drill pipe to turn the drill stem as the rotary table turns.*
44.
Kelly Bushing
A device fitted to the rotary table through which the kelly passes. It is the means by which the torque of the rotary table is transmitted to the kelly and to the drill stem. Also called the drive bushing.*
29 | Summer Training Report, Oil India Limited, Jodhpur
45. Kelly Spinner
A device for spinning the drill pipe. Replaces the spinning chain.*
46.
Mousehole
Shallow bores under the rig floor, usually lined with pipe, in which joints of drill pipe are temporarily suspended for later connection to the drill string.*
30 | Summer Training Report, Oil India Limited, Jodhpur
47. Mud Return Line
A trough or pipe, placed between the surface connections at the well bore and the shale shaker. Drilling mud flows through it upon its return to the surface from the hole.*
48. Ram Blowout Preventer
A blowout preventer that uses rams to seal off pressure on a hole that is with or without pipe. It is also called a ram preventer. Ram-type preventers have interchangeable ram blocks to accommodate different O.D. drill pipe, casing, or tubing.*
49. Rathole
A hole in the rig floor 30 to 35 feet deep, lined with casing that projects above the floor. The kelly is placed in the rathole when hoisting operations are in progress.*
31 | Summer Training Report, Oil India Limited, Jodhpur
50. Rotary Hose
The hose on a rotary drilling rig that conducts the drilling fluid from the mud pump and standpipe to the swivel and kelly; also called the mud hose or the kelly hose.*
51.
Rotary Table
The principal component of a rotary, or rotary machine, used to turn the drill stem and support the drilling assembly. It has a beveled gear arrangement to create the rotational motion and an opening into which bushings are fitted to drive and support the drilling assembly. Note the pipe spinner (in red) on the side of the swivel.*
32 | Summer Training Report, Oil India Limited, Jodhpur
52. Slips
Wedge-shaped pieces of metal with teeth or other gripping elements that are used to prevent pipe from slipping down into the hole or to hold pipe in place. Rotary slips fit around the drill pipe and wedge against the master bushing to support the pipe. Power slips are pneumatically or hydraulically actuated devices that allow the crew to dispense with the manual handling of slips when making a connection. Packers and other down hole equipment are secured in position by slips that engage the pipe by action directed at the surface.*
53.
Spinning Chain
A relatively short length of chain attached to the tong pull chain on the manual tongs used to make up drill pipe. The spinning chain is attached to the pull chain so that a crew member can wrap the spinning chain several times around the tool joint box of a joint of drill pipe suspended in the rotary table. After crew members stab the pin of another tool joint into the box end, one of them then grasps the end of the spinning chain and with a rapid upward motion of the wrist "throws the spinning chain"—that is, causes it to unwrap from the box and coil upward onto
the body of the joint stabbed into the box. The driller then actuates the makeup cathead to pull the chain off of the pipe body, which causes the pipe to spin and thus the pin threads to spin into the box.*
33 | Summer Training Report, Oil India Limited, Jodhpur
54.
Stairways
Stairs leading from one level to another. Protected with handrails.*
55.
Standpipe
A vertical pipe rising along the side of the derrick or mast. It joins the discharge line leading from the mud pump to the rotary hose and through which mud is pumped going into the hole.*
34 | Summer Training Report, Oil India Limited, Jodhpur
56.
Surface Casing
Usually the first casing to be run in a well. This is done after spudding-in so a blowout preventer can be installed before drilling is started.*
57. Substructure
The foundation on which the derrick or mast and usually the drawworks sit; contains space for storage and well control equipment.*
35 | Summer Training Report, Oil India Limited, Jodhpur
58.
Swivel
A rotary tool that is hung from the rotary hook and traveling block to suspend and permit free rotation of the drill stem. It also provides a connection for the rotary hose and a passageway for the flow of drilling fluid into the drill stem.*
59.
Tongs
The large wrenches used for turning when making up or breaking out drill pipe, casing, tubing, or other pipe; variously called casing tongs, rotary tongs, and so forth according to the specific use. Power tongs are pneumatically or hydraulically operated tools that spin the pipe up and, in some instances, apply the final makeup torque.*
36 | Summer Training Report, Oil India Limited, Jodhpur
60.
Walkways
An area cleared for moving through by personnel and protected with a handrail.*
61.
Weight Indicator
A device for measuring the weight of the drill string. Monthly calibration to calculated drill string weight is required by API.*
37 | Summer Training Report, Oil India Limited, Jodhpur
Processing diagram of drilling rig
38 | Summer Training Report, Oil India Limited, Jodhpur
39 | Summer Training Report, Oil India Limited, Jodhpur
Mud Logging Unit
Mud Logging at the Phulasar-1 is being carried out by M/s Geologging. Mud-logging is the continuous monitoring of drilling parameters, mud system and drill cuttings for detecting the presence or absence of hydrocarbons. One of the most important tasks during drilling for hydrocarbons is the determination of fluid content of porous formations. The principle use is in drilling wild cat or exploratory wells, where there is little or no geological control. This is not a method to present a picture of the subsurface or quantitatively determine occurrence of oil and gas. Mud-logging gives reliable qualitative information on occurrence of hydrocarbon and helps in minimizing coring, avoiding the possibility of missing a producing zone and evaluating sub-normal or abnormal pressures.
Operation of logging
Wire line logs are made using highly specialized equipment entirely separate from that used for drilling. Onshore, a motorized logging truck is used which brings its array of surface recorders, computers and a logging drum and cable to the drill site. Most modern logs are recorded digitally. The sampling rate will normally be once every 15 cm (6 in), although for some specialized logs it will be as low as 2.5 mm (0.1 in). An average well of say 2000 m will therefore be sampled over 12,000 times for each individual log, and for a suite of 8 or so typical logs, it will be sampled over 100,000 times (although for some new, specialized tools, this can be the sampling rate per meter.
40 | Summer Training Report, Oil India Limited, Jodhpur
Logging Truck
41 | Summer Training Report, Oil India Limited, Jodhpur
Christmas Tree(well no.22)
42 | Summer Training Report, Oil India Limited, Jodhpur
Visit to Dandewala Gas Processing Complex (DND GPC)
► A Gas Processing Plant constructed & commissioned in 1997 for Processing of Natural Gas produced from the three fields.
► Constructed at a distance of 35 kms from TVC (Tanot village complex).
► The gas produced from all the three fields (Tanot, Bagitibba, Dandewala fields) is cumulatively collected and processed at DND GPC.
► Processed gas from DND GPC is sent directly to our consumer GAIL India Ltd.
► Fire Hydrant watering facility along with Fire tender and Crew is always available at DND GPC for any fire emergency.
► The Processed gas dispatched to GAIL is further distributed to the ultimate consumer i.e. RRVUNL at Ramgarh Power Plant.
► Plant Capacity – 1 MMSCMD
► A 10 point gas gathering manifold
► 2 nos. of Production Separator and 1 no. of Test Separator for DND field.
► A single stage gas scrubber and filter system.
► Glycol dehydration plant.
► Reboiler unit for TEG purification.
► Two stage (MP & LP) condensate recovery system.
► Condensate storage tank 2 nos. (60 kls each).
► Flare stack (non luminous).
► Gas metering system (CTM).
43 | Summer Training Report, Oil India Limited, Jodhpur
Layout of DND-GPC
Production Manifold
Test Manifold
DND Production Separator
DND Test Separator
Pig Receiver
8” CS x 13 kms Tanot GGS to DND GPC pipeline
Tanot Production Separator
Filter Separator
Flare
To GAIL
GDU
Water Seal Glycol Scrubber
Reboiler Unit
Flare lines of other vessels
To Sump
MP Flash Drum LP Flash Drum
Condensate Storage Tank
Condensate Storage Tank
CTM
Drain line from other vessels
Glycol/Gas Exchanger
44 | Summer Training Report, Oil India Limited, Jodhpur
Problems and Hurdles (including Gas Quality)
As the major drive mechanism is bottom water drive, some of the low pressure wells have encountered severe water loading problem due to which they have been shut in and are out of production. Another constraint is the high percentage of CO2 in the produced gas. i. Water Loading of low pressure wells
ii. High Percentage of CO2
Recommendations i. Foaming the liquid water can enable the gas to lift water from the well. ii. Using smaller tubing or creating a lower well head pressure sometimes can keep mist
flowing. iii. The well can be unloaded by gas-lifting or pumping the liquids out of the well. iv. Heating the well bore can prevent oil condensation. v. Down-hole injection of water into an underlying disposal zone is another option. vi. However, liquid-loading is not always obvious and recognizing the liquid-loading
problem is not an easy task. A thorough diagnostic analysis of well data needs to be performed. The symptoms to look for include onset of liquid slugs at the surface of well, increasing difference between the tubing and casing pressures with time, sharp changes in gradient on a flowing pressure survey, and sharp drops in production decline curve.
vii. The economic benefits of CO2 removal from the natural gas and then supplying it to consumer can be studied.
viii. CO2 removal further ensures that less greenhouse gases are released into0 the atmosphere.
45 | Summer Training Report, Oil India Limited, Jodhpur
Conclusion
The gas produced at the Oil’s Rajasthan field predominantly has more percentage of CO2 which is undesirable and reduces the calorific value of the produced gas. Hence, the economics from selling this gas is less compared to the economics by selling the gas having low percentage of CO2. This can be achieved by installing a suitable CO2 stripping plant to remove the excess CO2. The removed CO2 may be utilized for fertilizers plants and other industries. The gas production rate has been primarily controlled by the demand of the consumers.
Another common problem for the wells is water loading due to presence of bottom water drive mechanism. The wells should be produced at a low bean to maintain the back pressure and cement integrity should be checked by recording cement bond logs and advanced logs such as CAST-V or USIT for identification of channeling behind the casing and casing integrity.
The Gas field at Rajasthan has vast potential and should be exploited by preparing an exhaustive development plan and drilling more development wells. At the same time, other probable consumers should be identified for higher economic viability.
![WELCOME [] SACHDEVA DIRECTOR SHREYA SRIVASTAVA DIRECTOR HIMANSHU KAKKAR DIRECTOR AVNISH PATI TRIPATHI DIRECTOR NIKHILENDRA SINGH DIRECTOR PRANJAL RAJPUT DIRECTOR BDC DEEPAK Title ...](https://static.documents.pub/doc/80x56/5ae32a1f7f8b9a097a8dcc62/welcome-sachdeva-director-shreya-srivastava-director-himanshu-kakkar-director.jpg)
