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CINGSA successes
Officials tell RCA gas storage progressing to support winter energy demand Alan Bailey for Petroleum News
The Cook Inlet Natural Gas Storage Alaska facility has experienced a successful summer, injecting gas into its reservoirs prior to the uptick in Southcentral Alaska gas demand as the winter approaches, CINGSA officials told the Regulatory Commission of Alaska during an Oct. 22 public meeting.
With Cook Inlet natural gas production dropping over the years and gas being the primary fuel used in Southcentral Alaska for heating buildings and generating electricity, gas storage has become essential to gas operations in the region.
The storage of excess gas produced during the summer can ensure that sufficient gas supplies can be delivered fast enough to meet high demand levels during cold winter conditions.
CINGSA went into operation in 2012 and since then has successfully been conducting its gas storage services.
Gas is stored in a depleted reservoir of the Cannery Loop gas field on the Kenai Peninsula, south of the city of Kenai.
Injections proceeded to plan CINGSA director of storage operations, Matt Federle, told the commission that while there had been minimal gas withdrawals during the summer this year, injections had proceeded to plan.
The amount of gas stored is now right around the 10 billion cubic feet level, Federle said. CINGSA's maximum rated capacity is 13 billion cubic feet, with the amount of gas being stored dependent on the facility's storage contracts with customers.
"We didn't have any interruptions to service that were unexpected for this reporting period," Federle said. There were some planned interruptions relating to planned projects, including modifications to the gas compressor fuel system.
The company also continues to have an excellent safety record, with most reportable incidents involving minor hand injuries, Federle said.
Well testing The potential clogging of wells by sand that may enter the well bores from the storage reservoir is one of the risks associated with the storage facility. In particular, sand can enter a well when gas is being withdrawn.
Over the years CINGSA has conducted testing of its wells, to verify the rates of gas withdrawal that can be sustained without significant sand incursion. This testing has applied to the original five wells in the facility.
Last year two additional wells were drilled -- these wells have yet to be tested.
Well 5 of the facility has proven problematic, with sand blockage reducing gas flow rates over the years and bringing the flow rate to very low levels by 2020. As a consequence, in 2021 CINGSA installed small diameter tubing, referred to as a velocity string, in the well. That brought gas flow rates up close to the rates achieved in the first year of CINGSA's operations, with the well continuing to perform effectively since then.
Based on this experience, CINGSA plans to fit a velocity string into well 4 next year, Federle said.
Additional control valve The only significant upgrade work conducted during the summer season was the installation of the pipework and fittings for an additional 4-inch diameter control valve for gas being delivered through one of CINGSA's gas withdrawal pipelines. The existing single 4-inch valve has inadequate throughput capacity to meet maximum customer withdrawal demand.
The use of two 4-inch valves operating in parallel will result in a more stable gas flow than would happen with a single 8-inch valve, Federle explained.
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