Alex Mills: Earthquake study raises more questions than it answers

The Texas Alliance of Energy Producers welcomes a recent study of seismic activity that determined a possible casual connection between water extraction and reinjection during oil and gas drilling and production activities, but there are many questions about the study.

The Alliance is very concerned that the study made conclusions based on a variety of assumptions, estimates, and uncertainties, and it looks forward to finding more details at hearings before the Texas Legislature and the RRC in the near future.

The Alliance believes that these occurrences have site-specific geologic characteristics, and regulation should be at the state level by the Texas Railroad Commission (RRC).

SMU released a study on April 21 that said water extracted during oil and gas operations and re-injected “is the most likely cause of earthquakes” near the North Texas town of Azle from November 2013 to January 2014. Even though the study pointed a finger at water extraction and re-injection, it did not recommend any solutions.

- FWBP Digital Partners -

Further, the study’s authors admit there were six key areas where findings were based on estimates because important scientific facts were not known to researchers. The uncertainties listed in the report are brine production, bottom-hole pressure, regional structural geology, stress magnitude and orientation, permeability and modeling.

The Alliance believes that given these many areas of concern that the researchers should have obtained more scientific data and conducted more analysis before releasing the paper.

Even the authors noted that “ultimately, better information on fluid volumes, flow parameters, and subsurface pressures in the region will provide more accurate estimates of the fluid pressure along this fault.”

The study also admitted that there are “many thousands of injection and/or production wells that are not associated with earthquakes.”

- Advertisement -

It is important to note that the Railroad Commission adopted changes to its disposal well rules in 2014. RRC regulations require a seismic risk assessment of the injection well location as well as ensuring that the operator will provide any additional information the RRC deems necessary as part of the permitting process.

The use of water during the drilling and completion process is also a regulated process. Water is recovered as crude oil and natural gas is produced, and it must be disposed of according to state regulatory standards. The recovered water generally has a high salt content, and it cannot be reused. Disposal well operators must seek a permit from the Texas Railroad Commission that states the zone where the water will be re-injected, the amount of water injected, and pressure limits.

Let the RRC do its work before jumping to conclusions and rushing to the courthouse.

Alex Mills is president of the Texas Alliance of Energy Producers