Looking to enhance oil recovery, BP Exploration (Alaska) is implementing a new pilot project at the Lisburne oil pool on the North Slope.
The process involves injecting seawater into the gas cap of the reservoir to increase pressure and produce more oil. The company estimates the process will help produce 500,000 additional barrels of oil over the next three years.
If successful, the pilot project could be expanded into a full program lasting 20 years, which BP estimates could add 10 million barrels of oil from Lisburne.
The Alaska Oil and Gas Conservation Commission approved the three-year pilot project on June 4, requiring BP to report annually on the progress of the program.
Lisburne production on steep declineLisburne is in the northeast corner of the Prudhoe Bay unit, part of a group of fields collectively known as the Greater Point McIntyre Area.
These fields have seen steady production declines every year for the past decade.
In filings with the state, BP said Lisburne alone produced an average of 10,222 barrels per day of oil in 2007, along with 1,457 bpd of natural gas liquids.
The state calculates Lisburne production along with several other fields. Through the first five months of this year, those fields produced an average of 36,400 bpd of oil. By comparison, the fields produced an average of 84,500 bpd through the first five months of 2001.
Some of the drop can be attributed to high gas-to-oil ratios at the field. The Lisburne Production Center can only handle so much gas.
As the facility began processing fluids from the nearby Point McIntyre and Niakuk oil pools in 1994, the operators began shutting in Lisburne wells with low oil ratios. Between 1997 and 2007, fewer than 41 of the 79 wells in the Lisburne oil pool have been active in any given month, according to BP filings.
Similar projects done at PrudhoeThe Lisburne field went into full production in 1987 and the operators at the time tried a two-year “pilot waterflood test,” but canceled the project after “Water breakthrough was much faster than expected.”
In 2002, BP implemented a much larger-scale version of the gas cap injection pilot project at Prudhoe Bay. According to filings, “There have been some early favorable results.”
Using models of Lisburne, BP predicts the injection “may act as a blocking agent” effectively keeping the gas in the reservoir from moving toward the production wells, thereby lowering the gas-to-oil ratio from the field.
BP doesn’t expect the project to decrease eventual gas production at the field and suggested it may even lead to slight increases in future gas recovery.