Cook Inlet Energy has received fines totaling $50,000 from the Alaska Oil and Gas Conservation Commission (AOGCC) — $25,000 for failing to test a new injection well from its Osprey oil platform and another $25,000 for failing to notify AOGCC when that well later showed “significant pressure anomalies,” according to AOGCC’s Monday order issuing the fines.
The Osprey platform, just south of the West Forelands on the west side of Cook Inlet, drills into the offshore Redoubt unit. In 2017 Cook Inlet Energy drilled and hydraulically fractured a sidetrack from one of the platform’s depleted wells.
The new sidetrack was meant to pressurize the reservoir with injections of water.
AOGCC mandates that “the mechanical integrity of an injection well must be demonstrated before injection begins” with a test witnessed by AOGCC staff. Cook Inlet Energy’s new well operated approximately six months without this test after it started continuous injections on July 1, 2017, according to AOGCC’s order.
Pressure in the well’s inner annulus — vacant space between a well’s tubing and its steel casing, through which fluids can flow — began to rise about 78 days after injection began.
Excess pressure in the inner annulus can cause fluid leaks or ruptures of the tubing.
“The field staff had to bleed it (the inner annulus pressure) down numerous times to keep it below 200 pounds per square inch,” AOGCC’s order states. Testing a theory that fluid from the well tube was entering the annulus and creating pressure, Cook Inlet Energy allowed the pressure to build to 1008 pounds per square inch over 79 days between August and November 2018. By doing so without notifying AOGCC, the order states that Cook Inlet Energy violated a rule requiring companies to notify AOGCC “by the next working day if an injection rate, operating pressure observation, or pressure test indicates pressure communication or leakage in any casing, tubing, or packer.”
Cook Inlet Energy had again bled off the excessive pressure by November 2017, but pressure built up again, reaching a maximum of 590 pounds per square inch, before it notified AOGCC of the issue on Dec. 18.
After the well passed a mechanical integrity test on Dec. 23, 2017, AOGCC concluded the well could safely continue injecting water, subject to monthly reports of its pressure and the installation of automatic shut-in equipment.
“Although no injury to the public occurred, the potential wellbore failure posed an obvious threat to both public health and the environment,” AOGCC’s order states. “… (Cook Inlet Energy’s) failure to comply with fundamental wellbore mechanical integrity testing requirements raises the potential for similar behavior with more serious consequences.”
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