Hilcorp gets OK for gas chiller project to boost Northstar output
Click here to go to the full PDF version of this issue, with any maps, photos or other artwork that appears in
some of the articles.
On Sept. 30 the Alaska Department of Natural Resources’ Division of Oil and Gas approved Hilcorp Alaska’s feed gas chiller project for Northstar Island, which will allow the company to increase natural gas liquid recovery during the summer months by holding the NGL separator at its optimum process temperature year round. This will boost the field’s annual sales oil production.
Hilcorp had applied for an amendment to its Northstar unit plan of operations on Aug. 29.
How much NGL output will increase was not provided in the company’s filing or the division’s decision, but NGL production this past summer averaged about 1,350 barrels per day, while the other nine cooler months averaged some 3,010 bpd, the difference being 1,660 bpd less for June, July and August.
Recently Alaska economist Ed King reported encouraging fiscal year 2019 output numbers from Hilcorp’s Northstar field, his data taken from the Alaska Oil and Gas Conservation Commission.
After starting regular production in 2001, the Northstar field is already nearing the end of its economic life, currently producing about 10,000 bpd of a combination of crude oil and NGLs for Hilcorp, he said.
However, Hilcorp, which purchased Northstar from its previous operator BP in 2014, has “a talent for getting oil out of fields that others are ready to give up on,” King said. “In fact, the Northstar unit saw an increase of 317,587 barrels of oil” (including NGLs) in FY 2019, a 9% increase over FY 18.
Among other things, Hilcorp’s tool chest to increase output from mature fields in Alaska and elsewhere includes more drilling, reworking wells, reinjecting natural gas and injecting polymer and water into reservoirs, employing and sometimes developing technology such as the chiller project, upgrading infrastructure to ensure that pipelines and wells can continue to perform effectively, plus the company has a robust integrity and management program for all its facilities and pipelines.
Scope and timingIn its description of the scope of the project, the division said Hilcorp had requested and been approved to install a chiller and a gas-to-gas heat exchanger on Northstar Island within the Northstar Island unit.
“Accompanying this new equipment will be a new motor control center, a propane compressor, condenser and receiver,” the agency said in its decision. “The chiller and gas-to-gas exchanger will be installed on top of the existing south process module.”
Per Hilcorp’s schedule, work on the chiller project was to begin immediately with gravel excavation to place concrete footings for a new steel support frame above the footings and modules, with a completion target of May 20 when things such as making electrical connections and installing additional infrastructure and tie-ins, as needed, will be done.
Northstar Island, the division said. is approximately 18 miles east of Milne Point. The gas chiller project will involve state lease ADL 312799.
Project activitiesPlanned project activities in Hilcorp’s words include the following:
* Excavation of gravel to allow footing installation from the existing artificial island.
* Installation of pre-cast concrete footings within the existing artificial island.
* Mounting a 110 foot by 14 foot steel support frame above the concrete footings.
* Securing a 45 foot by 14 foot by 14.5 foot in height compressor module.
* Securing a 45 foot by 14 foot by 14.5 foot in height receiver module.
* Securing a 20 foot by 12 foot by 14.5 foot in height motor control center, or MCC, building.
* Mounting a 100 foot by 12 foot steel support frame above the existing North pipe rack.
* Securing two 49 foot by 12 foot by 14.5 foot in height condensers.
* Removing two existing crude oil coolers from the roof of the South process module.
* Installing a vessel support frame on the roof of the South process module.
* Securing a 32 foot by 6 foot by 12.5 foot in height chiller vessel on the roof of the South process module.
* Securing two 43 foot by 5 foot by 7 foot in height gas-gas exchanger vessels on the roof of the South process module (the gas-gas exchanger vessels are in the same footprint as the chiller vessel).
* Installing approximately 400 feet of 24 inch process piping between the chiller, gas-gas exchanger, existing feed gas coolers and the existing NGL separator.
* Installing approximately 1,500 feet of propane piping, ranging in size from 3 inch to 14 inch, between the chiller, compressor module, condensers and receiver module.
* Installing electrical connections between the existing Northstar power system and the MCC building.
* Installing electrical connections between the existing MCC building and the two condensers.
* Installing additional infrastructure and tie-ins as required.
The division provided a review and comment opportunity for these activities, which ended Sept. 24. No comments were received.
- KAY CASHMAN