Hearing scheduled for Lookout pool rules
ConocoPhillips plans water alternating enriched gas injection for enhanced oil recovery at NPR-A Greater Moose’s Tooth accumulation
ConocoPhillips Alaska has applied to the Alaska Oil and Gas Conservation Commission for pool rules and an area injection order for the company’s Lookout oil pool in the Greater Moose’s Tooth unit in the National Petroleum Reserve-Alaska. AOGCC has scheduled a hearing on the application for 10 a.m. April 3 at its Anchorage offices.
Greater Moose’s Tooth is west of the Colville River unit and Lookout production will go to the Alpine central facility at that unit for processing.
The company said it is also applying for modification of the Colville River unit gas offtake order to allow gas from the unit to be provided to Lookout and for modification of allowable enhanced recovery fluid rules for several Colville River unit pools to allow injection of Lookout produced water.
Lookout is one of the discoveries announced in 2001 by ConocoPhillips Alaska predecessor Phillips Alaska, discoveries made after NPR-A was reopened to exploration in 1999. The company said in May 2001 that discoveries were made at five wells and a sidetrack drilled over the previous two winters - Spark 1 and Spark 1A, Moose’s Tooth C, Lookout 1, Rendezvous A and Rendezvous 2, while a sixth well, targeting a different interval, was a dry hole. The wells were believed to have encountered three separate hydrocarbon accumulations, the company said.
The Lookout oil pool will be the first production from the Greater Moose’s Tooth unit, where a $1 billion development is underway to complete the pad at Greater Moose’s Tooth and other infrastructure. First production is expected late this year, with GMT1 production expected to be 25,000 to 30,000 barrels per day.
Lookout oil poolConocoPhillips told the commission that the area covered by the Lookout oil pool was first assessed in 2001 and 2002 at the Lookout 1, Lookout 2 and Mitre 1 wells, with the Lookout wells both encountering hydrocarbons while the Mitre 1 was outside the reservoir limit.
The proposed Lookout oil pool contains Alpine C and Alpine D intervals, with the base of the pool defined by the Upper Jurassic Unconformity defined in the Lookout 1 well at 8,000 feet measured depth and 7,930 feet true vertical depth. The Alpine C and Alpine D intervals are from measured depths of 7,833 feet to 8,000 feet, and true vertical depths of 7,763 feet to 7,930 feet.
ConocoPhillips said the Lookout oil pool “is an oil accumulation formed by a stratigraphic trap of the shallow marine, Upper Jurassic Alpine C sandstone,” overlying the Kingak shale and underlying the Miluveach formation.
“A long-term interference test between Lookout 1 and Lookout 2 confirms reservoir connectivity over the majority of the reservoir,” the company said, with local compartmentalization possible in the southern portion.
Unit formed in 2008The Greater Mooses Tooth unit was formed in 2008 and a 2015 record of decision for a supplemental environmental impact statement covered the project to develop the Lookout oil pool, with the project to develop Lookout known as the Greater Moose’s Tooth 1 project sanctioned in 2015.
The company noted that GMT1 is the first development wholly within NPR-A.
The drill site is some 8 miles southwest of the CD5 drill site, with a permanent road connecting the two drill sites. There are four new pipelines for produced crude, water injection, miscible injection and gas lift. Nine horizontal wells, four producers and five injectors, are planned, with an injection program of water alternating with enriched gas injection to optimize recovery.
ConocoPhillips said Lookout is similar to the Alpine oil pool, “except Lookout does not have Alpine A sand present, does not include Kuparuk sands, has a lighter (higher API) oil and an associated higher solution gas-to-oil ratio,” and from an operational standpoint will be treated similar to Colville River unit oil pools.
PropertiesConocoPhillips said the API gravity at Lookout is 42.5.
Estimated original oil in place at Lookout is based on well data from the Lookout 1 and 2 wells, on seismic and on an interference test. Pre-development estimates of OOIP range from 70-150 million barrels, with a low estimate of 70 million barrels, a medium of 80 million barrels and a high of 150 million barrels. “Additional reservoir data from the planned development wells will enhance the understanding of sand distribution and may result in an update to the OOIP estimates,” the company said.
DevelopmentLookout will be developed with horizontal production and injection wells. Pilot holes are planned to provide additional reservoir data and assist in well placement.
ConocoPhillips said pressure support at Lookout will be maintained with water and gas injection and an enriched water alternating gas flood will be initiated early in the waterflood to improve ultimate recovery.
“Due to the expected reservoir throughput, the production wells are planned as unstimulated horizontal producers,” with two wells planned to have multilateral completions in the thicker section of the reservoir. The company said historical success of secondary and tertiary recovery mechanisms in the Alpine C sands at the Colville River unit “provides an analog for the expected performance” at Lookout. Because of the rock properties and waterflood mobility at Lookout, the expectation for ultimate recovery from enriched water alternating gas flood is expected to be in the range of 50-65 percent of original oil in place, the company said.
Primary recovery alone is expected to yield a 20 percent recovery, with remaining ultimate recovery from secondary and tertiary mechanisms with enriched water alternating gas injection, with an expected enhanced oil recovery of 12 percent and the remaining recovery “from pressure maintenance with waterflood support and depends on maintenance of voidage replacement.”
MT6 drill siteLookout will be developed from the new MT6 drill site, connected to the Alpine central facility for production processing and delivery of dry gas, enriched gas, water and electricity, ConocoPhillips said.
The company said MT6 will be a “not normally manned” drill site but said operators would be present every day except in extreme weather or other circumstances.
“The MT6 design requires minimal operator presence for operations. Monitoring of critical well and facility information, and routine operations, are accomplished remotely from the ACF control room.”
Crude oil from Lookout will move to CD5 in a 20-inch cross-country flowline where it will be commingled with CD5 production and flow on to the Alpine central facility. Water injection arrives via a new 14-inch flowline which connects both MT6 and CD5 to the Alpine central facility; enriched gas injection arrives via a 6-inch flowline connecting MT6 to the existing CD5 flowline.
The company said Lookout production is expected to be fully compatible with that from Colville River unit pools because Lookout and the Alpine oil pool “share a similar geologic history with the same oil charge source (Lower Kingak) and rock deposition source (Alpine A and B).”