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Husky McMullen Pilot To Test Development Of Thin Bitumen Reservoirs
The company is seeking Alberta Energy Resources Conservation Board and Alberta Environment approval for a steam-assisted gravity drainage (SAGD) pilot to produce up to 755 barrels (bbls) of bitumen a day.
Husky estimates its McMullen lease holds more than four billion bbls of bitumen in place. The lease includes 195 contiguous sections in townships 77 to 80, ranges 24 W4M to 2 W5M.
The project's central plant will be located in 10-10-79-1 W5M, about 25 kilometres southwest of Wabasca-Desmarais, Alberta, and 100 kilometres northeast of Slave Lake. The SAGD wells will be drilled from within the central plant footprint.
The target bitumen reservoir is the Wabiskaw member of the Clearwater formation. The net pay thickness is about 10 to 16.5 metres.
In its application Husky says there are no SAGD analogies targeting 10 to 15 metres of pay in the Wabiskaw.
Although the reservoir in the McMullen lease is laterally extensive, "the net pay thickness for this project is thinner than in most SAGD projects. The reservoir thickness is one of the biggest risks to the commercial development of this large resource," the application says.
"A successful outcome for this project would potentially provide useful operating information that would aid in the development of other thin reservoirs," Husky says.
With an overburden thickness of 400 to 550 metres, surface mining isn't considered an economic option. "This type of resource is currently only economically recoverable using in situ recovery methods," Husky says in its application.
Based on core samples, the bitumen (7.3- to 8.6-degree API gravity) viscosity is such that there is little or no mobility. Recovery methods such as SAGD or cyclic steam stimulation (CSS) are considered the only viable options.
"SAGD was chosen as the preferred oil recovery method over CSS because it provides several potential technological and environmental advantages," Husky's application says.
"Lower steam-injection pressures will minimize thermal stress on the wellbores and preserve reservoir integrity. With SAGD there is less chance of steam recycle than in CSS. There is also less chance of bottom water breakthrough in a thin reservoir using SAGD. Expected recovery factors from a SAGD process are in the range of 50% to 60%."
The proposed pilot's estimated capital cost is $35 million. It would start with one well pair that would be 750 to 900 metres long in the horizontal sections. The need for a second well pair will be assed based on initial results.
Pending regulatory approval, drilling and construction of well pads and surface facilities would start in June and will be completed by year's end. The pilot would run for three to five years.
Husky expects a recovery factor of about 38% after five years of SAGD operation. Produced natural gas will be conserved and used as fuel on site to reduce gas purchases.
The company estimates about 400 cubic metres a day of cold water equivalent will be converted to steam to produce 120 cubic metres a day of oil.
Development of the pilot will include drilling and operation of water source and disposal capacity which, if possible, will also be within the central plant footprint. To minimize surface disturbance, project facilities would be built on previously disturbed areas.
Heavy oil operations near the McMullen lease include the Bronco Energy Ltd. primary production scheme about 15 kilometres east of the McMullen lease and Canadian Natural Resources Limited's Brintnell polymer flood about 20 kilometres to the north.
Husky produces about 100,000 bbls a day of heavy oil in Western Canada. It also operates what it calls one of the world's best small thermal bitumen projects at Pikes Peak in the Lloydminster area of Saskatchewan. Pikes Peak is a former CSS project later converted to SAGD.
