Slim hole Drilling Slim hole Drilling Technology Technology

Presented b yPresented b y

Ary Kakashin Saber Anas Mahmood Ary Kakashin Saber Anas Mahmood Mohir Mohir

ContentsContents• Introduction .Introduction .• Why Slimhole Drilling?Why Slimhole Drilling?• Development& integrationDevelopment& integration• Slimhole Drilling ServicesSlimhole Drilling Services• Why did slimhole usage rapidly Why did slimhole usage rapidly

decline and almost disappear?decline and almost disappear?• Limitations & ImprovementsLimitations & Improvements• Cases history Cases history • ConclusionsConclusions

IntroductionIntroduction• The term slimhole (SHD) is widely used to The term slimhole (SHD) is widely used to

mean a range of smaller diameter drilling mean a range of smaller diameter drilling and casing sizes compared to those and casing sizes compared to those considered conventional in the oil and gas considered conventional in the oil and gas industry. industry.

• SHD was known in the 1950 , came back in SHD was known in the 1950 , came back in the late 80’s , received great attention in the late 80’s , received great attention in the 90’s.the 90’s.

• In today’s economic requirement must In today’s economic requirement must reduce costs , especially costs related to reduce costs , especially costs related to drilling exploration, One way to achieve drilling exploration, One way to achieve substantial cost reductions is to substantial cost reductions is to use slim use slim hole hole technology..

Slimhole & Conventional Slimhole & Conventional CompletionCompletion

Why Slimhole DrillingWhy Slimhole Drilling??

          

There are there major factor for There are there major factor for using slimholeusing slimhole: :

1- Economical Benefits .1- Economical Benefits .

2- Technical .2- Technical .

3- Environmental Benefits3- Environmental Benefits . .

11 - -Economical BenefitsEconomical Benefits

• Targeted drilling cost reduction in theTargeted drilling cost reduction in the above outlined scenario of 30 TO- above outlined scenario of 30 TO-

40%40% depending on well logistics and depending on well logistics and

geometry. geometry. •   Smaller rigs requires.Smaller rigs requires.• Fast move rig ( easy mob - demob ).Fast move rig ( easy mob - demob ).• Rig flexible and competitive for Rig flexible and competitive for

drilling and workover operationsdrilling and workover operations..

11 - -Economical BenefitsEconomical Benefits• Reducer of loads .Reducer of loads .• Reduction of hole size, and related Reduction of hole size, and related

equipment. equipment. •   Less transportation cost .Less transportation cost .• Less site preparations .Less site preparations .• Smaller wellbore have less expensiveSmaller wellbore have less expensive - Drilling tools- Drilling tools - Casing- Casing - Cementing- Cementing - drilling mud - drilling mud

..

Less Site PreparationsLess Site Preparations• Site reduced by 75%Site reduced by 75%

Slimhole Cost SavingSlimhole Cost Saving

Typical slimhole Well DesignTypical slimhole Well Design

Slim & Conventional CostSlim & Conventional Cost

22--TechnicalTechnical**** In Field Exploration That we can In Field Exploration That we can

determinedetermine 1. Lithology .1. Lithology . 2.Reservoir Pressure, and 2.Reservoir Pressure, and

Temperature .Temperature . 3. Reservoir Permeability (K) .3. Reservoir Permeability (K) .**** In Field Development In Field Development 1.Gas Wells .1.Gas Wells . 2.Tight Oil Reservoirs .2.Tight Oil Reservoirs .

33..Infill, and Reentry wells Infill, and Reentry wells (Developmen Wells(Developmen Wells Injection wells )Injection wells ). .

33--Environmental Environmental BenefitsBenefits1- Mud consumption and cutting reduced by 1- Mud consumption and cutting reduced by

75%75%

2- Reduced Area Cleared For Drilling up to 2- Reduced Area Cleared For Drilling up to 75% .75% .

3- Reduced Noise Impact . 3- Reduced Noise Impact .

4- Reduced Fuel Use & Emissions . 4- Reduced Fuel Use & Emissions .

5-Enhanced Protection of Sensitive 5-Enhanced Protection of Sensitive Environments. Environments.

6- More Friendly .6- More Friendly .

Development& Development& IntegrationIntegration

• Rig concept and design .Rig concept and design .

• Drilling efficiency .Drilling efficiency .

•Bit selection .Bit selection .

• Mud system and waste treatment .Mud system and waste treatment .

• Cementation . Cementation .

•Kick detection levelsKick detection levels

Rig Concept and DesignRig Concept and Design The main elements of a slim hole package are The main elements of a slim hole package are

perceived asperceived as::A - Main drilling unit and associatedA - Main drilling unit and associated equipment .equipment . - Support equipment (casing tools- Support equipment (casing tools,, cementing equipment), basic logging .cementing equipment), basic logging . - Drilling instrumentation and- Drilling instrumentation and information system .information system . - Mud system .- Mud system . - Multi-skilled crew- Multi-skilled crew

Rig Concept and DesignRig Concept and Design

B - Drill strings .B - Drill strings .

C - Specialist down hole tools .C - Specialist down hole tools .

D - Geo scientific data acquisition .D - Geo scientific data acquisition .

E - Communications system (especially for E - Communications system (especially for remote locations) .remote locations) .

F - Camp facility (remote locationF - Camp facility (remote location(( . .

G - Supporting Safety, Environmental and G - Supporting Safety, Environmental and Quality .Quality .

Drilling EfficiencyDrilling Efficiency

The slim hole drilling bottom hole The slim hole drilling bottom hole assembly (BHA) has been designed assembly (BHA) has been designed around two philosophies:around two philosophies:

1-Minimized longitudinal and torsional 1-Minimized longitudinal and torsional vibrations need to reduce drill string vibrations need to reduce drill string failure. failure.

2- The smaller diameter hole use of a 2- The smaller diameter hole use of a downhole motor will lead to improved downhole motor will lead to improved rates of penetration over rotary rates of penetration over rotary techniques . techniques .

Bit SelectionBit Selection

Criteria for bit selection were to:Criteria for bit selection were to:

1- Optimize penetration rates .1- Optimize penetration rates .

2- Produce reasonable sized 2- Produce reasonable sized cuttings for evaluation purposes cuttings for evaluation purposes with no secondary metamorphic with no secondary metamorphic effects. effects.

Mud System and Waste Mud System and Waste TreatmentTreatment• Slim Holes drilling requires very refined Slim Holes drilling requires very refined

mud characteristics especially the solid mud characteristics especially the solid content which must be as low as content which must be as low as possible. possible.

• Reduced the volumes of mud and Reduced the volumes of mud and cuttings protect the environment.cuttings protect the environment.

• To achieve this objective, the rig was To achieve this objective, the rig was equipped with an efficient shale shaker equipped with an efficient shale shaker and two high speed centrifuges. In and two high speed centrifuges. In order to reduce the volume of waste order to reduce the volume of waste the centrifugation .the centrifugation .

CementationCementation

• Slim Hole drilling program Slim Hole drilling program requires far less volume of slurry requires far less volume of slurry than a conventional one. than a conventional one.

• Therefore we elect to prepare Therefore we elect to prepare the slurry in two batch tanks and the slurry in two batch tanks and to pump it with the rig pumps. to pump it with the rig pumps.

Kick Detection LevelsKick Detection Levels• Because of the hole geometry, kick Because of the hole geometry, kick

detection is of extreme importance. To detection is of extreme importance. To provide for the safety of the personnel provide for the safety of the personnel and protect the environment weand protect the environment we must must detect a kick sooner than in a traditional detect a kick sooner than in a traditional hole size.hole size.

• This means that equipment had to be This means that equipment had to be engineered and tested to be able to engineered and tested to be able to detect an influx at a similar stage as is detect an influx at a similar stage as is now common in conventional .now common in conventional .

• Detecting and controlling a kick in time Detecting and controlling a kick in time generally results in no damage to the wellgenerally results in no damage to the well ..

Slimhole Drilling Slimhole Drilling ServicesServices

• There are three types of contractors There are three types of contractors providing slim hole drilling servicesproviding slim hole drilling services::

1-The mining drilling contractors who 1-The mining drilling contractors who basically focus on continuous coring basically focus on continuous coring application .application .

2-The oil and gas conventional drilling 2-The oil and gas conventional drilling contractors who provide conventional contractors who provide conventional and purpose build drilling rigs .and purpose build drilling rigs .

3-Service contractors who provide 3-Service contractors who provide coiled tubing unitcoiled tubing unit. .

Why did slim hole usage Why did slim hole usage rapidly decline and almost rapidly decline and almost

disappeardisappear?? • Past problem associated with slimhole Past problem associated with slimhole

drilling : drilling :     

  1-The lack of reported blow outs while 1-The lack of reported blow outs while drilling .drilling .

2-Reduced bore hole diameter limited the 2-Reduced bore hole diameter limited the stimulation possibilities (fracture, injection stimulation possibilities (fracture, injection rate), production rate, and inability to do rate), production rate, and inability to do multi connectionmulti connection..

3-Inability to log test, cement, fishing3-Inability to log test, cement, fishing

Slimhole Drilling Slimhole Drilling CharacterizesCharacterizes1-Technical and safety risks are no more severe 1-Technical and safety risks are no more severe

than with conventional drilling :than with conventional drilling :-    -    There are existing well control system to There are existing well control system to

detect small fluid influxes. Well control detect small fluid influxes. Well control slimhole is no more risky than with slimhole is no more risky than with conventionalconventional..

-   -   Drilling fluid for slimhole system are as Drilling fluid for slimhole system are as critical as with conventional drilling system .critical as with conventional drilling system .

Testing and fishing in small diameter borehole Testing and fishing in small diameter borehole is possibly less risky than with conventional is possibly less risky than with conventional systemsystem

Slimhole Drilling Slimhole Drilling CharacterizesCharacterizes2-Cementing a narrow annulus slimhole 2-Cementing a narrow annulus slimhole

well using existing good cementing well using existing good cementing practice provides an adequate seal .practice provides an adequate seal .

3-Almost every wire line log can be run in 3-Almost every wire line log can be run in slimhole down to a diameter of 4 1/8”, slimhole down to a diameter of 4 1/8”, smaller than this diameter there are still smaller than this diameter there are still enough logs to evaluate a well .enough logs to evaluate a well .

4-Directional work in slim hole is a 4-Directional work in slim hole is a standard practice where smaller standard practice where smaller diameter mud motors are reliable (less diameter mud motors are reliable (less expensive than the big motor) .expensive than the big motor) .

Limitations & Limitations & ImprovementsImprovements

****            LimitationsLimitations 1- 1-   Logging & Testing .Logging & Testing . 2- Bit Availability .2- Bit Availability . 3- 3- Small Clearance (STUCKS)Small Clearance (STUCKS) .. 4-4-        Cementing .Cementing .

****            ImprovementsImprovements 1-1-          Slim hole Logging Tools .Slim hole Logging Tools . 2-2-          Arrangements with manufacturers .Arrangements with manufacturers . 3-3-          Special BHA .Special BHA . 4- Improved Slurries .4- Improved Slurries .

Cases HistoriesCases Histories

**Location Paris Basin Wells**Location Paris Basin Wells : :

• 1-/ 1A1-/ 1A

-Drilling :3 phases ( 8 1/2“ -Drilling :3 phases ( 8 1/2“ -- 6“ - 3 3/8 6“ - 3 3/8( (

-The actual duration was 32 days-The actual duration was 32 days

-Phase 8 1/2" casing 7“ Depth : (11 to 176 )m -Phase 8 1/2" casing 7“ Depth : (11 to 176 )m

Total duration 4 days. During this phase no Total duration 4 days. During this phase no major problem. Which is common in this major problem. Which is common in this region.region.

Cases HistoriesCases Histories

- Phase 6" casing 4 1/2" - drilling from (176 - Phase 6" casing 4 1/2" - drilling from (176 to 922to 922(( m , Total duration 9 days no major m , Total duration 9 days no major problem with drilling except an extra trip problem with drilling except an extra trip as a PDC bit got burn while drilling through as a PDC bit got burn while drilling through chirt - Maximum deviation 4"chirt - Maximum deviation 4"

- Phase 3 3/8"- Phase 3 3/8" t totalotal duration 16 days - duration 16 days - drilling from 922 m to 1983 m drilling from 922 m to 1983 m 

- Economical results : savings were 27% .- Economical results : savings were 27% .

Cases HistoriesCases Histories

• 2- TETRAS 12- TETRAS 1 -The actual duration was 37 days. -The actual duration was 37 days.

-Drilling casing program, 9 5/8" casing 7 -Drilling casing program, 9 5/8" casing 7 5/8"5/8" at 155 m, 6 3/4” Casing 5 1/2”, at at 155 m, 6 3/4” Casing 5 1/2”, at 1598 m, 4 3/4" to 2026 m.1598 m, 4 3/4" to 2026 m.

-Economical results : savings were 47% .-Economical results : savings were 47% .

ConclusionsConclusions

1-SlimhoLe technology recently has been 1-SlimhoLe technology recently has been established as a proven alternative to established as a proven alternative to conventional drilling operations.conventional drilling operations.

2-Now that the drilling community has 2-Now that the drilling community has shown that slimhole can reach the shown that slimhole can reach the objective and is both technically and objective and is both technically and economically feasible, completion and economically feasible, completion and production aspects of small wellbore production aspects of small wellbore receive the focus of increased attention.receive the focus of increased attention.

3- The following factors should improve the 3- The following factors should improve the

use of slimhole in the futureuse of slimhole in the future

- Continued drive to reduce all cost- Continued drive to reduce all cost

- More recompletions out of old wellbore .- More recompletions out of old wellbore .

-Environmental pressure continue to -Environmental pressure continue to increase ,increase ,

-More use of continuous of coring and -More use of continuous of coring and stratigraphic wellsstratigraphic wells

- Contractors need to replace old equipment .- Contractors need to replace old equipment .

- New technical capabilities using slimhole - New technical capabilities using slimhole completion and production equipment .completion and production equipment .

ReferencesReferences

• SPE papers SPE papers