CINGSA plans to increase the storage capacity at its gas storage facility on the Kenai Peninsula, John Sims, CINGSA president, told the Regulatory Commission of Alaska on Oct. 25. Sims said that CINGSA will soon be filing paperwork for RCA approval of the expansion. The concept includes the drilling of two new wells in the existing facility, he said. The facility currently has five wells and stores gas in what used to be a subsurface sand reservoir of the Cannery Loop gas field, south of the city of Kenai.
As previously reported by Petroleum News, CINGSA held an open season earlier this year seeking bids for firm additional gas storage. Sims said that the company received bids from two of its existing customers. CINGSA has also recently signed an agreement with Marathon Petroleum for interruptible gas storage services, he said.
A vital role
CINGSA plays a vital role in Southcentral Alaska by enabling its customers to store excess produced gas when gas demand is low, especially during the summer, and then to retrieve the gas during high winter demand. Without the CINGSA storage facility, utilities in Southcentral would be unable to obtain gas at high enough flow rates to meet their customers winter needs.
The gas supply situation in the Cook Inlet region is moving towards a crisis point, with the possibility of annual supplies falling short of annual demand in a few years time. And, with also being president of Enstar Natural Gas Co., Sims is well aware of the emerging challenges.
"One of the biggest changes that has happened here in the Cook Inlet is the producers hesitancy to contract for firm gas supplies," Sims said. "Thats been one of the biggest challenges that Enstar has seen, and all of the utilities have seen."
This trend leads to a need for the utilities to have the capability to store gas, to maintain their committed supplies regardless of interruptions in their supplies of gas from producers.
"Thats one of the reasons that we are looking at this," Sims said. "Thats something that all the utilities are looking at collectively and collaboratively."
A quiet year for operations
Matthew Federle, CINGSA director of storage operations, told the commission that this has been "a pretty quiet year for operations," with no really big gas withdrawals or injections. During the summer the balance of gas stored in the facility peaked at barely 10 billion cubic feet before starting to fall, as the weather cooled. The maximum capacity of the facility is 11 billion cubic feet.
The facility has two surface pads, on either side of a road. One pad holds the wellheads, while the other pad has gas compression facilities. A 16-inch pipe that passes under the road transports gas between the wells and the compression facility, feeding gas into wells for storage and retrieving gas when required for customer use.
Pig launcher/receivers
To meet federal regulations for monitoring any corrosion within a gas pipeline running under a road, CINGSA is going to install a pig that can inspect the interior of the pipeline. Last year the company installed a pig launcher/receiver at the compressor end of the pipeline. This year the company has been installing a launcher/receiver at the well end.
And, having upgraded the facility compressor system last year, CINGSA has now added a booster pump for the cooler for the compressor. The company installed the pump and cooling fan in positions where any noise from the system will not disturb local residents, Federle said.
CINGSA has also been upgrading the programmable controllers for the facilitys equipment. The entire CINGSA facility is fully automated, Federle said.
Managing well capabilities
One issue that CINGSA has had to deal with since its facility went into operation in 2012 is the potential for sand from the reservoir rock entering and blocking the wells. This can happen if the gas flow rate into a well exceeds some threshold level when gas is being delivered from the well. Sims commented that, initially, CINGSA had thought that this drawdown limit would apply evenly across all of the wells. However, over time it has become evident that each well has different characteristics.
As a consequence, CINGSA has been conducting tests to determine, for each well, maximum safe gas drawdown rates at different gas inventory levels. The ability to conduct testing depends on the vagaries of how much gas inventory the facility holds at any particular time. That, in turn, depends on the manner in which CINGSAs customers are using the facility.
To date CINGSA has been able to complete the testing for all of the wells for inventory levels above 8 billion cubic feet, and for three of the wells at inventory levels between 5 billion and 8 billion cubic feet. Inventory levels have not so far been low enough to conduct testing at levels below 5 billion cubic feet. The test results enable CINGSA to operate each well at safe levels while also maximizing its use, Federle said.
"We are continuing to learn about this facility," Federle said. "We are continuing to learn about each well. And that process is going to continue."
