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Conoco drilling at GMT2 in NPR-A with first production by year end
Kristen Nelson Petroleum News
ConocoPhillips Alaska spud its first development well at Greater Mooses Tooth 2 in the National Petroleum Reserve-Alaska on April 27, the company told the Alaska Oil and Gas Conservation Commission May 25 in a hearing on an application for pool rules for the Rendezvous oil pool at GMT2.
Production engineer Dana Glessner said the first development well at GMT2 was spud April 27, following two construction seasons, with final installation of facilities and pipelines this year and first production and injection expected in the fourth quarter.
Rendezvous is ConocoPhillips’ second development in the Greater Mooses Tooth unit, 8 miles southwest of the initial development at GMT1, the Lookout oil pool, she said.
Exploration drilling occurred in the area in 2000-04 with Rendezvous 2 drilled and flow tested in 2008, followed by Rendezvous 3 in 2014.
Development in southern area There are nine wells in the pool which are plugged and abandoned (Altamura 1, Carbon 1, Moose’s Tooth C, Rendezvous 2, Rendezvous A, Spark DD-9, Spark 1, Spark 1A and Spark 4) and two suspended wells (Rendezvous 3 and Scout 1).
Although there is a gas cap at the Greater Mooses Tooth unit north of the Rendezvous oil pool, Glessner said, identified when the Spark wells were drilled, development focus is on the oil.
There are 36 initial wells planned, 18 producers and 18 injectors, with production, like that from GMT1, routed to the Alpine central facilities for final processing. A potential 12 additional wells are extended reach drilling targets.
Doyon 25 is being used for the 36-well program; Doyon 26 would be used for extended reach targets, Glessner said.
The initial 36-well development plan is horizontal wells with lateral lengths in the reservoir from 10,000 to 18,000 feet, with the northern wells to be drilled under the gas cap.
Development will be with enriched water alternating gas flood, she said, as at other Alpine reservoirs.
Geology Development geologist Garrett Timmerman said Rendezvous is a stratigraphic trap with the Alpine sand interval, C and D, contained by Miluveach shale above and Kingak shale below, and oil sourced from the Lower Kingak.
The northern wells in the development, Timmerman said, will be drilled underneath the gas cap and terminated before intersecting the gas.
The Rendezvous 2 well is in the core of the development area, he said, with the pool interval from 8,229 to 8,393 feet measured depth.
ConocoPhillips would like both Alpine C and Alpine D to be considered for the pool, Timmerman said.
API gravity at Rendezvous is 37.2 degrees. The reservoir is a little tighter than Alpine, he said, with a little lower permeability and porosity.
Within the Rendezvous pool, rock quality tends to be a little better to the north.
Glessner said they planned to begin injection with seawater and switch to produced water as that becomes available.
Estimated recovery Reservoir engineer Joe Versteeg, discussing fluid properties, said they expected a very efficient flood.
Original oil in place is estimated to be 300 million to 460 million barrels, with primary recovery estimated at 20%, a range of 60 million to 92 million barrels, Versteeg said.
Primary recovery plus enriched water alternating gas, EWAG, flood is estimated at 35-60% of OOIP, 105 million to 276 million barrels, with original gas in place estimated at 1.7 trillion to 2.8 trillion cubic feet, with an estimated yield range of 30 to 60 barrels per million standard cubic feet.
He said production is projected out to 2050 or so, describing it as a long life, low permeability reservoir with low throughput.
The company is looking at the gas, he said, but no gas development plan has matured.
This is an oil rim only development, designed to minimize gas coning and manage the gas-oil-ratio. Versteeg said the goal is to drill the northern row of wells under the gas cap to maximize the physical offset and also to maximize injection with a target ratio of 1.0 between injection and withdrawal.
The plan is to have a couple of injectors on to start production, with gas injection to occur after six to 12 months. He said they wanted a good slug of water before beginning gas injection.
Oil production will be in a range of 20,000 to 45,000 barrels per day, with the cap on peak production the onsite production separator. He said they expected a pretty slow flood, so a slow ramp up in water production.
From the injection side they are projecting a range of 20,000 to 50,000 barrels of water per day and 20 million to 70 million cubic feet of gas.
Versteeg said projected production at GMT2 was so much lower than Alpine because of the separator constraint and the lower permeability environment than at Alpine.
Drilling plan Drilling engineer Nina Anderson said the program for 36 horizontal wells is a similar drilling program to that at CD5. The key focus is maintaining hole conditions and wellbore stability because of the shales in the area, she said.
The initial 36 wells will be drilled with a 16-inch surface hole, she said, although 20-inch surface hole will be required for the ERD wells.
Timmerman said the thickness of the shale package in the area causes the concern with hole stability.
Metering, fluids Glessner said AOGCC approved the GMT2 production measurement and allocation system in late 2018. She said GMT2, like GMT1, will have both a test separator and production separator on site, with production metered after three-phase separation on the drill site before transport and commingling with GMT1 and other Colville River unit pools.
In September ConocoPhillips applied to AOGCC for final measurement approval of the fiscal allocation metering system for GMT2.
Water and gas for Rendezvous pool injection will come from the Alpine central facility, and gas will be measured before leaving the Colville River unit, with gas and water injection at GMT2 also measured at each individual injector.
She said the company expects Rendezvous production to be fully compatible with Lookout, GMT1, and other Colville River pools.
Rendezvous is a close analog to the Alpine pool with both sharing a similar geologic history and the same oil charge source from the Lower Kingak.
Glessner said drilling of the initial 36 wells is expected to be completed by the end of 2024.
- KRISTEN NELSON
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