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

During Drilling

During Completion (includes HF) Well Integrity “WI” During Drilling 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 Development Phase: Well Specific Economics Exploration Phase: Determine Commercial Value
Basis of Design for a Development Well

Consider a Time Line Perspective Case Study not unlike Marcellus and Eagle FordEPA Hydraulic Fracturing Study Technical 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

Natural Separation of Protected Water and Hydrocarbons Protected water = USDW < 10,000 mg/l TDS Will not discuss the natural migration of gas, oil, brineEPA 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 arrivesEPA 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 prescribed depth
Drilled in less than a day – Open for a short period only Typically drilled with air or water based systemEPA 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 requirements Significant 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 drilledEPA 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 job Failure 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 cement sheath & 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 #2EPA 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 shoe and adjacent formation together
Assessment of well‟s ability to withstand pressure to the next casing point Not a leak-off test, it does not establish a limit
For our case study well we are now at the end of day #3EPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 9 of 22 – Next section of hole is drilled

Depth for the next hole section is not prescribed, as for the surface casing Safe drilling operations and not wasting minerals are the general guidelines For our case study well this section takes a week, now at end of day #10EPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 10 of 22 – Intermediate string of casing is run

Safe drilling operations and not wasting minerals are the general guidelines For our case study well this section takes a week, now at end of day #11EPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 11 of 22 – Intermediate casing is cemented and tested

Cement is the primary barrier for vertical migration of fluids The first attempt aka „primary cement job‟ is most critical for well integrity All other attempts aka “remedial cement jobs” have lower success rates Less prescriptive regulations than for the surface casing cement job Cement sets- up, then casing and cement float equipment is tested together Failure categories; insufficient volume, low bond strength, sheath damage Remedy is to perforate the casing and squeeze Strong correlation between poor cement sheath and external casing corrosion Strong correlation between poor cement sheath and gas / fluid migration Intermediate casing on case study well is cemented by the end of day #12EPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 12 of 22 – Intermediate casing shoe and formation integrity are tested

The FIT tests the casing shoe and adjacent formation together Not a leak-off test, it does not establish a limit Assessment of well‟s ability to withstand pressure to the next casing point For our case study well we are now at the end of day #13EPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 13 of 22 – Next section of hole is drilled

Depth for the next hole section is not prescribed, as for the surface casing Safe drilling operations and not wasting minerals are the general guidelines For our case study well this section takes 2 weeks, now at end of day #27EPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 14 of 22 – Production casing is run

Safe drilling operations and not wasting minerals are the general guidelines For our case study well,this takes 2 days, now at end of day #29EPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 15 of 22 – Production casing is cemented, Drilling phase is done

Cement is the primary barrier for vertical migration of fluids The first attempt aka „primary cement job‟ is most critical for well integrity All other attempts aka “remedial cement jobs” have lower success rates Less prescriptive regulations than for the surface casing cement job Failure categories; insufficient volume, low bond strength, sheath damage Remedy is to perforate the casing and squeeze Strong correlation between poor cement sheath and external casing corrosion Strong correlation between poor cement sheath and gas / fluid migration Production casing on our case study well is cemented by the end of day #30 Drilling operations are done, Well Integrity is pretty much determinedEPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 16 of 22 – Completion phase: perforate, hydraulically frac, flowback, production begins

Frac flowback period varies from days to weeks, Completion ops are done Monitor all annulus pressures

Production casing and cement float equipment are tested together Completion phase begins

Production phase begins, basically this is how it looks for next 30 years The production casing is perforated & frac‟ed stage by stage, “toe” to “heel”
After the final frac stage is pumped, drill out the isolation plugs During the frac monitor injection pressures, rates, and annular pressuresEPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 17 of 22 – Refrac and Adjacent Well Frac Scenarios

Squeeze cement, frac string, wellhead saver can protect weak components Well integrity during a refrac is all about planning, pressures, and rates Refracs require well specific analysis to identify potential weak links Hydraulic fracturing activity on this well might impact our adjacent case study well if our well‟s cement is absent or not sufficient to withstand the conditions imposed on it Monitor all annulus pressuresEPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 18 of 22 – Plug and Abandonment begins, producing zone is plugged and tested

30 years later, all the reserves have been produced, P&A begins A cement plug is the primary barrier for isolating the hydrocarbon zoneEPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 19 of 22 – Casing is cut or perforated near the surface casing shoe

Production casing is cut, bridge plug is set in the intermediate casingEPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 20 of 22 – Cement plug is set across the surface casing shoe and tested

A cement plug set across the surface casing shoeEPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 21 of 22 – Shallow surface plug is set and tested

A cement plug set near the surfaceEPA Hydraulic Fracturing Study Technical Workshop #2 March 10 - 11, 2011 Well Integrity Case Study by Lloyd H. Hetrick Slide 22 of 22 – Pipe cut-off, cap welded, well ID marker, backfill

All strings are cut and capped, well ID marker, then backfilled with soil