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BP applies for S pad expansion for Ugnu Research continues on CHOPS, cold heavy oil production with sand, technology; more space needed for equipment, light drilling Kristen Nelson Petroleum News
BP Exploration (Alaska) has applied to expand S pad in the Milne Point unit for a test of Ugnu production and for continued development of the Schrader Bluff reservoir.
The company told regulators the project would involve placement of some 99,000 cubic yards of clean gravel fill into not more than 11.1 acres of wetlands. Work is expected to begin as soon as permits are received, the company said in its application.
The expansion at the northwest end of S pad would support a new well row, allowing for drilling of additional pilot heavy oil wells.
The company drilled the Coho 1 well last summer to test cold heavy oil production with sand, or CHOPS technology. BP told regulators that the pad expansion would allow for the drilling of additional pilot heavy oil wells, with two additional CHOPS wells and one horizontal well planned on the existing well row where Coho 1, test well Milne Point S37, is located.
In addition to CHOPS wells on the well row, BP is also planning additional light oil development wells, so a new row is needed for additional heavy oil wells. The new well row will be oriented so new wells can avoid interference with existing subsurface locations and also provide for a simpler line of sight on the subsurface to the Ugnu formation.
Partial processing planned The COHO 1 well and three new CHOPS wells planned on the existing well row would be supported by the first surface partial processing test kit, planned for installation in the first half of 2009. Wells on the new well row would be serviced with a second test kit placed on the new gravel expansion. Space is also allowed for sand hauling trucks to turn around; additional surface kits would be permitted at a later date.
The southern and western edges of the pad require extension so a second rig and other equipment can move around an existing drill rig already in use on the pad. BP told regulators that “CHOPS wells require quick access to workover rigs as high sand rates can require more frequent unplanned rig workovers. Down time on CHOPS wells must be minimized during critical 100-150 day startup periods in order to minimize the risk of ‘losing’ or sanding off the well.”
North and eastern edge pad expansion is needed because trucks going to the north edge of the pad must backup down the well row due to limited space on the pad. “Management of the sand and production fluids coming from the CHOPS well will increase truck traffic on the pad significantly,” BP said, and additional space is needed on the pad to minimize risks from simultaneous operations on the pad.
Multiple wells needed for testing CHOPS S Pad was constructed in 2001 and the northwest end of the pad was extended in 2007 so equipment could be placed to test MP S37, the Coho 1 well, drilled in 2006 into the Ugnu formation to test CHOPS technology. Gravel for the extension was placed in September 2007 to allow time for it to compact and settle before the extended well test program, planned for August, BP said.
BP said it could conduct a single test at S pad without altering the pad’s existing footprint, but a minimum number of wells, seven to nine, are needed to effectively test the technology on the North Slope and the existing S pad footprint does not provide the area needed for the wells.
Also, test operations for CHOPS would impede access on the pad for drilling and completion of additional light oil wells or maintenance of existing wells.
Well operations for heavy oil CHOPS wells require mobilization of many different types of heavy equipment and pre-pilot well testing is expected to last up to five years, the company said.
No decision on further drilling BP Exploration (Alaska) spokesman Steve Rinehart told Petroleum News that BP drilled the Coho 1 well last summer and will continue research on that well.
BP had planned additional CHOPS drilling this summer, but that’s something that hasn’t been finalized yet, Rinehart said. Work will continue on the well drilled last summer but the number of wells to be drilled this summer has not yet been determined.
Rinehart said the goal this year is to get Ugnu hydrocarbon to the surface and experiment with a couple of ways to heat it up and get the sand out. The formation is down some 3,000 feet — below the permafrost which goes down to 1,800 or 2,000 feet, he said. The sedimentary rock is not very consolidated and CHOPS attempts to take advantage of that by sucking the oil out with the sand, drawing the sand out like a wormhole, creating a network of channels that the oil could move into.
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