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Greater Point McIntyre delivers BP updates development plans for series of fields that continue to produce oil in the northern part of the Greater Prudhoe Bay unit Alan Bailey Petroleum News
In addition to the giant Prudhoe Bay field itself, several smaller oil fields have for many years been producing oil within the Greater Prudhoe Bay unit on Alaska’s North Slope. At the end of June BP, the unit operator, filed the latest plan of development for a group of these fields in what is referred to as the Greater Point McIntyre Area, in the northern part of the unit.
Lisburne The fields in this area deliver oil and gas through the production facilities for the Lisburne field, a field discovered at the same time as Prudhoe Bay, with a reservoir in carbonate rocks below the main Prudhoe Bay reservoir. Other fields in the Greater Point McIntyre Area consist of Niakuk, Point McIntyre, Raven, West Beach and North Prudhoe Bay.
The Lisburne field, with an estimated volume of original oil in place of 1.8 billion barrels, came on line in 1986. According to data from the Alaska Oil and Gas Conservation Commission, by the end of 2013 the field had produced 163 million barrels of oil. BP’s plan of development for Lisburne says that the field delivered 2.4 million barrels of oil between April 2013 and March 2014.
From the perspective of reservoir management and production planning, BP divides the field into three areas: the west, central and east areas. And, according to information on the BP website, in recent years the company has used horizontal, coiled-tubing drilling to bolster production rates from the field - coiled tubing drilling involves the use of a continuous length of small-diameter, flexible drill pipe to thread a near-horizontal well through pockets of oil in an oil reservoir. The use of geoscience techniques to locate faults and fractures in the rocks helps guide drilling strategies, the BP website says.
Gas dissolved in the oil and in the gas cap above the oil, coupled with water injection, drives oil up production wells in the east and west areas. In the central area dissolved gas, supplemented by an influx of subterranean water and some injected water, drives production, the development plan says.
Water injection In the eastern area a pilot test of water injection into the gas cap will be extended to July 2016. The extension period will enable a determination of the effectiveness of the injection program, including an evaluation of factors such as incremental oil production resulting from the injection and the reservoir pressure response in productions wells, the plan of development says. Conversion of three production wells for seawater injection was completed in 2013, the plan says.
In the field as a whole, several new wells are being considered for drilling in 2015, the plan says.
Throughput in the Lisburne processing facility is currently constrained by the relatively high volumes of gas produced along with the oil. However, gas is re-injected into the oil reservoir to maintain reservoir pressure.
Point McIntyre The Point McIntyre field, after which the northern part of the Greater Prudhoe Bay unit is named, had an estimated oil in place volume of 800 million barrels when the field was discovered in 1988 in reservoir rocks equivalent to those of the neighboring Kuparuk field. The field went into production in 1993 and at the end of 2013 had a cumulative oil production of 448 million barrels. According to the field’s plan of development, oil, condensate and natural gas liquids production averaged 18,500 barrels per day between April 2013 and March 2014.
BP is applying what is referred to as a tertiary oil recovery process at Point McIntyre, alternately injecting water and a material called miscible injectant into the field’s reservoir. Miscible injectant, a mixture of natural gas and natural gas liquids, acts a solvent, flushing oil from rock pores, while water sweeps the oil toward production wells. BP says that it is designing reservoir management and oil recovery strategies that will optimize oil production rates and oil recovery from the field, but that oil production will continue to decline as increasing quantities of water and gas are produced along with the oil.
Sidetrack drilling However, BP says that it is evaluating the possibility of drilling some new sidetrack wells off existing wells, with the possibility of developing some pockets of oil bypassed by earlier drilling. The company is also assessing development opportunities in the west and northwest areas of the field, where rock quality is generally poor, the plan says.
The plan also says that a new 3-D seismic survey scheduled for completion by the end of 2014 may enable the identification of further drilling opportunities.
BP is also figuring out a strategy for dealing with a flow line within the field that had to be taken out of service because of corrosion concerns.
Niakuk Like the Point McIntyre field, Niakuk has an oil reservoir in rocks equivalent to those of the reservoir of the Kuparuk field. The field held an estimated 300 million barrels of oil in place when it was discovered in 1985. Production began in 1994 and by the end of 2013 the field had produced 93 million barrels of oil. The field’s plan of development says that the field produced 884,000 barrels of oil between April 2013 and March 2014.
The Niakuk reservoir is located offshore and is accessed by means of wells directionally drilled from land.
The geologic complexity of the field precludes the use of a uniform pattern of production and injection wells, the plan says. Production profiles and data from pressure surveys are used in a dynamic reservoir management strategy involving techniques such as selective well perforation. BP is also evaluating the use of Bright Water, a technique used to direct the flow of injected water through a subsurface reservoir, to improve oil production in the field.
And, as with Point McIntyre, the results of a new 3-D seismic survey may enable the identification of some new drilling targets, the development plan says.
Raven The Raven field, also offshore the North Slope, went into production in 2006, producing oil from an isolated pool in rocks equivalent to those of the reservoirs of the Prudhoe Bay field. The volume of oil and condensate in place was estimated at between 14 million and 23 million barrels. Nearly 3 million barrels of oil had been produced from the field by the end of 2013. The plan of development for the field says that the field delivered 110,000 barrels of oil between April 2013 and March 2014.
BP uses a water flood strategy for oil production, with the field having a single production well and a single injection well.
West Beach West Beach went into production in 1993 but production was suspended indefinitely in 2001 because of an increasing gas-to-oil ratio and declining reservoir pressure. And although 11 wells, including four sidetrack wells, have been drilled in the field, about 92 percent of the field’s total production of 3.37 million barrels of oil have come from the field’s original well, the field’s development plan says.
Although reservoir pressure has increase since the suspension of production, and despite several efforts to revitalize the field, including well work and some production testing, it has not yet been possible to restore production from the field. BP says that it is going to use the results of some production testing conducted in 2009, in conjunction with a revised geologic model for the field, to evaluate future development options. New 3-D seismic data will also help in an evaluation of new opportunities, the plan says.
Production has been shut in since 2000 from the single production well in the North Prudhoe Bay field because of safety concerns involving proppant used during fracture stimulation of the field reservoir. BP says that it may evaluate potential future development opportunities in this field.
Gas sales? In the development plans for the various Greater Point McIntyre fields, BP alludes to the possibility of a future gas line from the North Slope, commenting that future gas sales from the fields would require the availability of a gas transportation system. Meantime, the gas will be consumed for field operations or re-injected into the subsurface, the plans say. In total the fields produced about 109 billion cubic feet of gas between April 2013 and March 2014, with the bulk of that gas coming from the Lisburne and Point McIntyre fields.
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