The Railroad Commission of Texas (RRC) amended its oil and gas well construction requirements rule (Statewide Rule 13) to clarify requirements related to casing, cementing, drilling, well control and completions. The changes take effect Jan. 1, 2014 and apply to any wells drilled on or after that date.
For wells undergoing hydraulic fracturing treatments, operators are now required to pressure test well casings to the maximum pressure expected during the fracture treatment and to notify the RRC of a failed test. Also during hydraulic fracturing, operators are required to monitor the annular space between the well's casings for pressure changes (which could indicate a leak in casing) and suspend fracking if the annuli monitoring indicates a potential down hole casing leak.
Operators must also now isolate (place cement behind casing) across and above all formations that have a permit for an injection or disposal well within one-quarter mile of a proposed well and must obtain RRC approval before setting surface casing to a depth exceeding 3,500 feet.
The changes establish additional testing and monitoring requirements for "minimum separation wells" where the vertical distance between the base of usable quality water and the top of a formation to undergo fracking is less than 1,000 vertical feet. "This provision involves a limited number of vertical wells that are vertically hydraulically fractured in a handful of shallow fields, which are found in the Abilene, Midland, San Antonio and Wichita Falls areas and does not involve horizontally completed and hydraulically fractured wells in the major plays in the Barnett Shale, Eagle Ford Shale and Permian Basin," the commission said.
Operators are required to use air, fresh water or fresh water-based drilling mud until surface casing is set and cemented in a well to protect usable quality groundwater and are required to pump sufficient cement to isolate and control annular gas migration and isolate potential flow zones and zones with corrosive formation fluids.
References to cement quality, cementing, well equipment, well casing centralizers and well control have been updated, and standards of minimum cement sheath thickness of at least 0.75 inches around the surface casing and a minimum cement sheath thickness of 0.50 inches around subsequent casing strings have been established.
Requirements for well control and blowout preventers have been consolidated and updated, and the requirements distinguish between the use of well control equipment on inland, bay and offshore wells.
The changes also implement Article 2 of HB 2694 to reflect the transfer of the Texas Commission on Environmental Quality's surface casing section to the RRC, where it is now called the groundwater advisory unit. "As usable quality groundwater depth varies statewide, this unit establishes the depth of surface casing required for each well to protect groundwater," RRC said.
"These new rule amendments will provide our oil and gas operators with consistent and clear regulations," said RRC Commissioner Christi Craddick. "They also enhance the Railroad Commission's ongoing effectiveness in overseeing the responsible development of our domestic energy resources, which has resulted in one of this nation's greatest economic success stories."