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Going for gas
BlueCrest is looking at tapping into Cosmopolitan’s huge gas accumulation
Kay Cashman Petroleum News
BlueCrest Alaska Operating is making plans to tap into the Cosmopolitan unit’s 5,000-foot-thick natural gas dome that lies above the Hansen field oil accumulation - and is considering using subsea completions to do it.
“We are seriously studying it right now,” J. Benjamin Johnson, company director, told Petroleum News in a May 29 interview that included company President John M. Martineck.
“This gas field is not related to the oil; it is a separate field lying directly above the oil but not connected to it,” Johnson said.
BlueCrest brought the southern Cook Inlet unit into production in 2016 (after 49 years of failed attempts by previous operators), using state-of-the-art extended-reach drilling technology and a custom-built drilling rig to access the offshore oil reserves from an onshore drill site and production facility about 5 miles north of Anchor Point on the Kenai Peninsula.
The oil wells are being drilled about 3 miles out and 1.5 miles down to reach the edge of the reservoir. Then the wells traverse an additional 1.5 miles horizontally through the productive sands. The company said in 2018 it has seven years of drilling targets in the oil reservoir.
BlueCrest has increased Cosmopolitan oil production from 275 barrels of oil per day in July 2017 to 1,562 bpd in March; it also produces a small amount of associated natural gas.
Of the 15 wells completed in the field in 2018, 13 were sidetracks, part of BlueCrest’s innovative development strategy of utilizing a “fishbone” well pattern, with a single “spine” well running from the surface. That spine well is deviated to run through the lower part of the oil reservoir, with sidetrack “rib” wells drilled upwards every 800 feet into reservoir rock above the spine.
While aggressively pursuing oil, the company has held off going after the natural gas in the dome, which is too shallow to be accessed from onshore drilling.
Separate gas field “We discovered the gas field in 2013,” Johnson said, which is when BlueCrest and its former partner Buccaneer Energy drilled the Cosmopolitan 1 vertical well with the Endeavour jack-up rig. (BlueCrest bought out Buccaneer in 2014 and took over as operator.)
“We logged it, cored it and flow tested it,” Johnson said. “In addition, we have very high resolution 3-D seismic and we can see each one of the major zones, see the structure. We can see any faults and there are none in the field except for the fault at the north of the field and at the south end of the field.”
Martineck said the company has “confirmed the 3-D seismic with all the wells we’ve drilled. We can see the gas sands are continuous. We know it is a large field … and with no water.”
The Ninilchik gas field to the north is very similar to BlueCrest’s gas field: “We’d be producing from the same horizon, the Tyonek,” Johnson said, noting “most other inlet gas fields are produced from the shallower Beluga and Sterling formations.”
A pair of the Tyonek sands tested at Cosmopolitan 1 flowed at 7.2 million and 7.3 million cubic feet per day with no water, Buccaneer said at the time.
Simple subsea completions The conventional development scenario in Cook Inlet has been offshore platforms.
“We are still looking at putting in a single platform but modern technology is leading us to look at subsea completions,” Martineck said. “It would be a very clean, very simple system ... and this particular location in Alaska would be very well suited” to it.
“The water depth is only 70 feet,” he said. “They’d be the first subsea completions in Alaska but very simple compared to what’s done around the world in much harsher environments. It would be a walk in the park for the guys who do those completions, and it would allow us to recover more gas in the end.”
There would be nothing to see from the surface, Johnson pointed out.
“This development would be done in an area that contains no liquid hydrocarbons; it’s 100% methane, there’s no oil that comes up from the gas zones,” he said.
“We also do not have any ice on the water in this location, a little bit but nothing major,” Johnson said.
The wells would be drilled with a jack-up, but “when we’ve finished drilling, the jack-up leaves,” Martineck said.
The gas would be transported by a “3-mile pipeline from the wells to our surface location,” Johnson said. “We’re already set up for gas in our facility. We’d have to make some changes to our onshore facility, but they’d be minor.”
The existing 8-inch Enstar line, which can currently deliver 50 million to 55 million cubic feet of gas per day, could be substantially expanded with specialized equipment, so no new transmission line would have to be built to feed the gas into the main Enstar line.
Once the jack-up was on site, they said, several wells would be drilled.
“There can be significant production; it just depends on how many wells we drill,” Johnson said.
No firm decision has been made on how BlueCrest will tap its huge gas dome, “but we’re very seriously evaluating it right now … but it won’t be done this year,” Martineck said.
The owner of BlueCrest Alaska Operating, Texas-based BlueCrest Energy, is a privately held independent exploration and production
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