Trabajo de integridad de casing

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EPA Hydraulic Fracturing Study Technical Workshop #2 March 10-11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 1 of 22 – Well Integrity Narrowly Defined as the Prevention of Fluids Migration into Protected Water

Exploration Phase: Determine Commercial Value During Drilling Development Phase: Well Specific Economics Basis of Design for a Development Well Well Integrity “WI” DuringDrilling WI During Completion (includes hyd fracturing) WI During Operations (includes re-fracturing) WI During Plug and Abandonment Full Life Cycle View Discuss Jurisdiction, Regulations, Best Practices Consider Failure Categories, Modes, Relative Rates Consider a Time Line Perspective Case Study not unlike Marcellus During Completion (includes HF) and Eagle Ford

EPA Hydraulic Fracturing StudyTechnical Workshop #2 March 10-11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 2 of 22 – Jurisdiction

Federal and State Environmental Laws

State Mineral Law (Federal if BLM, BIA Minerals)

State Mineral Law (Federal if BLM, BIA Minerals)

EPA Hydraulic Fracturing Study Technical Workshop #2 March 10-11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 3 of 22 –Natural Separation of Protected Water and Hydrocarbons, in most cases

Protected water = USDW < 10,000 mg/l TDS Natural Separation of Protected Water and Hydrocarbons Will not discuss the natural migration of gas, oil, brine

EPA Hydraulic Fracturing Study Technical Workshop #2 March 10-11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 4 of 22 – Spud well with conductor pipe (driven,augered or drilled) no impact on Protected Water

Structural, not always needed

Does not penetrate the base of protected water Typically installed before the rig arrives

EPA Hydraulic Fracturing Study Technical Workshop #2 March 10-11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 5 of 22 – Well is drilled to a prescribed depth below Protected Water

Drilled to a prescribeddepth

Typically drilled with air or water based system Drilled in less than a day – Open for a short period only

EPA Hydraulic Fracturing Study Technical Workshop #2 March 10-11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 6 of 22 – Surface casing is run

Primary barrier from wellbore fluids when drilling the next interval Never optional; Extensive regulatory requirementsSignificant body of industry best practices for running and testing casing Failure categories: materials, connections, handling, mechanical, corrosion External corrosion is most common failure mode

Remedies may include external coatings, cement, cathodic system Surface casing is run the same day the surface hole is drilled

EPA Hydraulic Fracturing Study Technical Workshop #2 March 10-11,2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 7 of 22 – Surface casing is cemented and tested

Cement is the primary barrier for vertical migration of fluids into USDWs The first attempt aka „primary cement job‟ is most critical for well integrity All other attempts aka “remedial cement jobs” have lower success rates Prescriptive regulatory requirements apply to this cement jobFailure to comply triggers agency notification and remedial actions Significant body of industry guidance and best practices for cementing Cement sets-up, then casing and cement float equipment is tested together Failure categories; insufficient volume, low bond strength, sheath damage Remedies include: pumping in, top job, perforate the casing and squeezing

Strong correlation between poor cementsheath & external casing corrosion Strong correlation between poor cement sheath & gas / fluid migration Surface casing on our case study well is cemented at the end of day #2

EPA Hydraulic Fracturing Study Technical Workshop #2 March 10-11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 8 of 22 – Surface casing shoe and formation are integrity is tested

The FIT tests the casing...
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