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1 Well Scenarios Ade Adeyemi

Well Scenarios

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Page 1: Well Scenarios

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Well Scenarios

Ade Adeyemi

Page 2: Well Scenarios

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Problem 1 – Wellbore “Thief Zone”

Weatherford have been approached by the Drilling Engineer of ChriSuth Petroleum.

On reviewing the planned well construction schematic there are concerns the completion hole size will have to be downsized.

• The planned completion hole size is 7”.

• Planned TD depth of 8 ½ hole” is 3464.45m MD, TVD 2349m

• Previous casing 9 5/8”depth is 2874.44m MD.

• There is one trouble some zone over the depth interval 3045-3056m MD where they expect a “thief zone”.

• They also expect another however cannot guarantee the depth of troublesome zone.

13 3/8” Casing

7” Liner

9 5/8” Casing

16” Casing

20” Casing

Proposed Casing Design

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Problem 1 - Solution Required

Based on your understanding of the problem please give your recommendations to the Drilling Engineer……

Your solution must be effective in meeting the following objectives required

• The 7” cased hole section may not be downsized due to production requirements

• They do not want to spent time with LCM trying to cure the troublesome zone

• Your recommendation must effectively provide a solution to overcome the known “thief zone” without compromising the hole size.

• Your recommendation must also by able to counter act the possibility of another zone again without comprising the intended completion hole size.

Please present your solution, with procedure for operation and reasoning for selection

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Problem 1 – Solution Answer

Weatherford’s MetalSkin Monobore Open-Hole Clad system would be an ideal candidate to fulfil the requirement

• The hole size would be able to be maintained without compromising hole size after installation

• No time need be spent with LCM additives

• It is possible to overcome counter act another troublesome zone that may be encountered after previous installation. This again would not compromise hole size and no time need be spent with LCM.

• Where conventional methods would require casing to be set early and loss of hole size the MetalSkin Clad System provides drilling security

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Problem 2 – Wellbore “Get on Line”

Weatherford have been approached by the Drilling Engineer of Star Petroleum.

On reviewing the proposed wellbore trajectory a swellable formation will be encountered

• The planned hole size is 17 1/2”.

• Planned section interval of the 17 1/2” hole is 270.5 - 305.6m MD

• Cost of oil is at an all time high and reservoir studies show this has huge potential for production

• There are 12 wells to be batch set all in the same vicinity of this wellbore. Formations are not expected to differ from this wellbore.

• Star Petroleum are keen to improve their time vs depth times. They are also keen in reducing risk and mitigating against hole problems and unstable formations.

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Problem 2 - Solution Required

Based on your understanding of the problem please give your recommendations to the Company Drilling Representative……

Your solution must be effective in meeting the following objectives required

• Your recommendation must be effective and proven that will improve the companies operation time vs depth charts

• Will counteract against the swellable formation

• May not affect the proposed wellbore construction planned status

• Your recommendation may not increase the health and safety greater than conventional methods of construction

Please give your recommendation stating your suggested method meeting objectives and advantages over conventional method

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Problem 2 - Solution Answer

Weatherford’s DWC (Drilling with Casing) would be an ideal candidate to fulfil the requirement

• Improvement of depth vs time charts would be improved by the eradicating the need for tripping to case the open hole section. This in return improves well costs, elimination of problem associated with tripping and eliminating unnecessary hazards.

• The problem formation would be isolated as soon as it is drilled

• The proposed well construction phase would not be affected

• Utilising DWC has benefits of improved safety eliminating hazards associated with tripping and casing wellbores.

• DWC can also overcome unexpected challenging hole problems isolating these as soon as they are drilled

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Problem 3 – Wellbore “Everything to Nuts and Bolts”

Weatherford have been approached by J & K Oil & Gas Limited.

On reviewing the proposed ERD wellbore trajectory, they are concerned about the following problems that they feel will jeopardise the successfully completion of drilling and successful installation of proposed casing string.

• The planned hole size is 12 ¼””.

• Planned section interval of the 12 ¼”” hole is 2250 - 3480m MD

• The inclination of the 12 ¼” builds from 68 deg to 89 deg at TD

• High side forces are expected at the start of the build section, and gradually decrease towards tangent section.

• Geo-steering will be used in the horizontal section, ledges within the wellbore is a possibility in the upper build section.

• Offset wells suggest this well construction phase is difficult however targeted reservoir dictates 12 ¼” section.

• Previous wells have experienced poor cement jobs which has allowed gas communication and allowed gas to raise to surface , this must be eradicated.

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Problem 3 – Additional Information

Lo-TAD

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Problem 3 - Solution Required

Based on your understanding of the problem please give your recommendations to the class……

Your solution must be effective in meeting the following objectives required

• Your recommendation must be effective in being able to successfully drill the 12 ¼” section in a timely manner counteracting against the forces that ultimately result in friction and limit the drilling and completion phase

• Will improve the chances of reducing/eradicating the gas flow to surface within the annuals.

• Will be able to mitigate against the possible ledging within the wellbore

Please give your recommendation stating your suggested solutions meeting objectives and advantages of using such technologies.

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Problem 3 - Solution Answer

Weatherford products such as Lo-TAD, Centralisers and Reamer Shoe would be candidates in meeting the following requirements.

• The Lo-TAD drilling sub is a complete mechanical friction-reduction system that performs independently off drilling fluids. LoTAD tools have been used in extended-reach wells where the objective is to reduce torque, axial drag while tripping in and out of the borehole, casing wear, tool-joint wear, and differential sticking, while also improving directional control, rates of penetration (ROP), are also additional benefits

• The ability to allow gas to communicate between annuals may have primarily been caused by poor cementation job. Centralisation of the casing string will prevent channelling which is a major contributor to cementation failure

• Weatherford’s ReamerShoe with Ledgerider eccentric guide nose with directional flow ports helps manoeuvre the casing past ledges and washouts. As the tool moves forward, it therefore tries “to climb over the obstruction”.

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Problem 3 - Solution Answer

Lo-TAD

Reamer Shoe

SpiraGlider

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Problem 4 – Wellbore “Increase Production Size”

Weatherford have been approached by BPPH Oil & Gas Limited.

On reviewing the proposed wellbore trajectory and proposed well construction opposite. They wish to review current new technologies and implement these to the proposed wellbore. It is hope this will ultimately result in increased production rates and increase revenue return for planned investment.

Top hole there have been many issues where trouble some zones has resulted in the casing having to be prematurely set. This has resulted in decrease in planned wellbore size, additional cost in utilising a extra casing string and fears additional zones will further reduce hole size.

13 3/8” Casing

7” Liner

9 5/8” Casing

16” Casing

18” Casing

22” Casing

Proposed Casing Design

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Problem 4 - Solution Required

Based on your understanding of technologies please give your recommendations to the class……

Reviewing the proposed wellbore schematic, what technologies would you propose to meet the following objectives.

• Save costs and time in the construction phase

• Maintain the wellbore completion size and possibly reduce a casing string.

• Deepen the wellbore to penetrate deeper reservoirs.

• Provisional solution that will maintain hole size should trouble some zone be encountered

Please explain your choice of this technology and the benefits it would bring to BHHP Oil & Gas Limited

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Problem 4 - Solution Answers

Weatherford products such as MetalSkin Monobore Open-Hole Liner System with Oversize shoe, Open-Hole Clad System, & Open-Hole Liner System may be considered to meet the requirements set.

• By utilising the 11 ¾” x 13 3/8” MetalSkin Monobore Open-Hole Liner system with oversize shoe we could eliminate the 16” liner hanger this would reduce time and cost and would not alter the 13 3/8” proposed status.

• MetalSkin Monobore Open-Hole Liner System with oversize shoe could be utilised to deepen the wellbore. The liner extension is then run to total depth and back into oversized shoe. Further advantage is increased wellbore completion size at required depth, increased production.

• Open-Hole Clad System could be utilised when a troublesome formation is encountered. This would not result in the hole size being downsized and reduces the need to overcome the trouble some formation with LCM.

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Always Avoid This!!!!!!!!