Study: Casing, cement at fault | Denton Record Chronicle | News for Denton County, Texas

The number of Texas wells experiencing integrity issues may be small, but the problem was big enough for the Texas Railroad Commission last year to establish a revision to Statewide Rule 13, which added stricter regulations for oil and gas drillers to follow when constructing a well.Everley, of Energy in Depth, said well-integrity issues are “an exceptionally rare occurrence,” happening in fewer than 1 percent of wells drilled across the country and, in Texas, well-integrity failure affected 0.01 percent of all wells drilled and completed in a 25-year period.Cyrus Reed, conservation director of the Sierra Club’s Lone Star Chapter, said in response, “In the grand scheme of things, [1 percent] might not be a lot; but if you’re in that area that relies on that water, 1 percent is too much.”Railroad Commission data on regulatory violations is important because it allows the public to get more information about oil and gas drilling.Prior to 2012, violations were separated into categories but not available to the public. For example, in 2009 the commission issued more than 2,800 violations in a category that encompassed casing, cementing, drilling and completion problems, according to data the agency provided to the Texas Sunset Advisory Commission. In 2012, the commission started posting online for the public a summary of violation statistics that grouped categories together.The change in how the commission decided to report violation data resulted in the public having less ability to understand the nature of the violations. In 2014, more than 45,500 violations were identified, but members of the public cannot tell what those violations specifically involved.“Violations cited under the commission’s Statewide Rule 13 do not mean a well has faulty cementing,” said Ramona Nye, spokeswoman for the Railroad Commission. “[They] could be cited for numerous reasons, including bradenhead pressure found on a wellbore, no wellhead control, no proper wellhead equipment installed, no cashing head valves plumbed to surface, etc.”There are numerous ways well integrity could be compromised.Adam Peltz, an attorney for the Environmental Defense Fund, said a casing could corrode or crack. If engineers don’t know about a subsurface void, the cement could go into the void, he said.“If you cement over an area with a flow of gas, there is a 15-minute window when the cement is liquid,” Peltz said. “During that setting time, gases and fluids can migrate up [the space] between the casings and get into places you don’t want them to go. It can happen in a very short period of time, and it’s not obvious.”Another issue is the increase in earthquakes in North Texas affecting established shale gas wells’ integrity.“It’s a relatively new phenomenon,” he said. “The science is still catching up.”The Environmental Defense Fund has developed the “Model Regulatory Framework for Hydraulically Fractured and Hydrocarbon Production Wells” to provide state governments a “road map” in implementing regulations that govern subsurface aspects of the drilling, casing and cementing process.The document offers what the environmental advocacy group thinks is “the state-of-the-art well integrity” to protect groundwater. Peltz said it was developed in conjunction with a variety of industry players and nonprofits.“We’ve been sharing this document with regulators and [putting it] in front of policymakers,” he said, in the hope that it can be “universally applied to make sure enforcement and oversight is adequate.”

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