Canadian operators are expanding a world class natural gas play in the Monkman area of eastern British Columbia.
The area, in the foothills of the Canadian Rockies near Fort St. John, B.C., has yielded a string of significant gas discoveries.
A number of companies-the most active BP Resources Canada Ltd. and Ocelot Energy Inc., Calgary-are playing a 30 mile wide by 50 mile long trend centering on two main producing horizons.
The new successes are being scored in an area that first attracted the attention of explorationists in the 1950s.
And the play's extent is still far from defined.
Other participants in the play include Mobil Oil Canada Ltd., Phillips Petroleum Canada Ltd., Petro-Canada, Amoco Canada Petroleum Co., Shell Canada Ltd., Encor Inc., and Texaco Canada Petroleum Inc.
Since 1988, companies in the area have acquired more than 3,600 line miles of seismic data at a cost of about $116 million, American Association of Petroleum Geologists' Explorer reported in its June 1992 issue. They have spent more than $75 million to acquire leases on more than 632,500 acres in the area.
BP Canada Pres. Jim Buckee earlier this year said the Monkman trend is developing into a world class gas play, being recognized as having the best reserves and deliverability potential of any gas play in western Canada, if not North America. That assessment was based on 17 discoveries out of 20 wells drilled by industry in the area since 1987.
AREA HISTORY
BP's strong track record in the area is based on long involvement.
Triad Oil, which later became BP Canada, began exploring there in 1956 with its first seismic surveys in 1959.
Seismic surveys in the 1960s yielded a few discoveries in the Sukunka and Grizzly areas, but there were more misses than hits.
The BP et al. Bullmoose d-77-E well in 1975 with 236 ft of net pay confirmed the potential for large reserves.
A major discovery at West Sukunka in 1979 that flowed 51 MMcfd of gas added to interest in the area.
Production from Sukunka and Bullmoose fields began in 1980 after completion of a pipeline and gas processing plant, and West Sukunka came on line in 1981.
AAPG Explorer reported activity in the area lagged in the 1980s due to low gas prices, the Canadian National Energy Program's restriction of export sales, and a series of unsuccessful wells in the expensive play.
But by the end of the 1980s West Sukunka field had some production history behind it, and reserves estimates jumped from about 40 bcf in 1979 to about 320 bcf a decade later based on new pressure data, Explorer reported.
RENEWED INTEREST
Doug McLean, reservoir geologist with British Columbia Ministry of Energy, Mines, and Petroleum Resources, believes renewed interest in the Monkman area is due in part to advances in seismic technology.
The area is highly thrusted, and McLean said companies are mainly targeting the fractured Triassic Pardonet and Baldonnel formations on the leading edge of the thrust sheets.
"The thrust faulting causes a very steep overturned limb on the front, and what the companies try to do is run the borehole down and intersect the steep-and in some cases overturned-limb of the thrust. That is where they get the maximum production. They can actually drill down the limb of the fold and get tremendous pay sections. Its almost like a horizontal well," McLean said.
McLean said BP and Ocelot have been very successful in drilling the limbs and crests of folds, but he has also seen them drill as many as four wells from the same location to try and hit the right spot.
The area is known to be prone to feature gas containing hydrogen sulfide, but McLean said recent structures found more to the west seem to have less H2S. "That seems to have helped the play quite a bit," he said.
"The most exciting thing about the play is ... some of the gas rates, but also the potential that it seems to be showing. This foothills play is just starting and there's land on strike on either side, to the north and south.
"The other interesting thing is that there are deeper potential horizons, too. There may be a Permian play as well down another 2,000 m."
McLean said one of the wells in the area intersected Permian pay in a similar geologic setting.
"I haven't seen seismic over it, but obviously it's thrust controlled and it's in the Gwillam area," he said.
McLean said cumulative production as of Dec. 31, 1991, from the three producing fields, Sukunka, Bullmoose, and West Bullmoose, is 142 bcf.
BP'S MONKMAN CAMPAIGN
Monkman successes have provided a strong launch for the birth of BP Canada as an independent company. Ties with the British parent company were cut earlier this year (OGJ, May 18, p. 33).
BP and partners have spent more than $145 million (Canadian) on exploration in the area, including $25 million for seismic data and $17.2 million for leases.
BP is the largest registered landholder in the area with 150,000 net acres.
The Monkman area was credited at midyear with more than 1 tcf of proved reserves. And the British Columbia government earlier estimated ultimate potential resource in the two main producing formations at 10.7 tcf. There have been several discoveries since then.
The best result disclosed to date was BP's Brazion a-70-E well last April at the northwest end of the play (OGJ, Apr. 20, p. 118). With about 700 ft of gross pay, it flowed 85 MMcfd, one of the highest initial flow rates recorded for a well in Canada.
BP said results from tests at Brazion represent only the section that has been drilled and not the full closure of the structure, which could be two to three times as thick as the Brazion pay.
There is an added bonus in the Brazion reservoir. It carries an H2S content of only 8% compared with a previous low of 18% in West Sukunka field. That will translate into less shrinkage, lower processing costs, and greater gas sales.
BP also disclosed results for its BP-Amoco Sukunka c-62-D well, about 7 miles southeast of Brazion, that flowed 41 MMcfd from 525 ft of gross pay.
Explorer reported the c-62-D well extended the Sukunka trend 6 miles north. The Brazion well, still further north, is on a separate structure.
And Mobil earlier this year reported a Sukunka success a little further east with its Mobil-Phillips Sukunka d-70-I wildcat, which flowed sour gas at a rate of 29 MMcfd from a 348 ft interval in Baldonnel. The well was drilled to total depth of 11,792 ft.
WHAT'S AHEAD FOR BP
BP partners in various projects include Ocelot, Amoco, Esso Resources Canada Ltd., and Sceptre Resources Ltd.
Since Brazion, BP and partners have drilled or licensed six more wells in the West Sukunka, West Bullmoose, and Burnt River areas including:
- BP-Ocelot Industries Ltd. West Bullmoose d-33-H test, completed as a gas well flowing 12-20 MMcfd.
- BP-Ocelot Wolverine b-30-C, south of the main Sukunka-Bullmoose trend suspended as noncommercial.
- BP-Amoco S. Brazion b-2-E, 5 miles southeast of Brazion a 70-E and north of Sukunka, last month flowed 75 MMcfd of gas on cleanup and 50 MMcfd through a restricted choke during 4 days. It cut 525 ft of gross pay.
- BP-Amoco Sukunka a-6-F, drilling ahead in mid-September. Both Burnt River projects are with Amoco as partner.
- BP d-39-C, another Burnt River location, scheduled to spud in October.
- BP Murray d-57-J, a new location in the south with Esso and Sceptre.
BP and partners are preparing to extend their play into the Murray River area at the south end of the trend where Petro-Canada has been successful.
Ted Bogle, exploration vice-president for BP, says the overall trend in the Monkman area eventually could extend as far as 90 miles north to south.
Bogle says the Monkman trend extends south almost to the Alberta border but is not proven. At the south end, he says, the Triassic section starts to outcrop, and there's a certain risk in drilling southern locations.
The BP executive noted Petro-Canada has drilled a successful well to the south and that there is production in the Grizzly area.
"I think it is time for us to move south again. We have drilled d-33-H (West Bullmoose) and b-30-C (Wolverine) south of the main pools," Bogle said.
"Now, we're going to move down to Murray River and get a feeling for what's down there."
PETRO-CANADA'S DISCOVERY
Petro-Canada established the southeast end of the play to date with a successful test at Murray River in the Grizzly Valley, about 90 miles south of Fort St. John.
Petro-Canada said flow tests indicated an initial capacity of 40 MMcfd at line pressure.
Petro-Canada is operator with a 50% working interest in the well. Its partners include Phillips, Amoco, Encor, and Texaco.
Petro-Canada said the successful wildcat has high deliverability, low H2S content, and is close to pipeline and processing facilities.
The company is drilling a delineation well just east of the discovery and plans to spud a second well to the west in November. Phillips is a partner in the operation.
Petro-Canada holds more than 217 sq miles of land in the area. It plans to continue exploration for tie-in of production to an expansion of Westcoast Energy Inc.'s Pine River gas processing plant in 1994.
OCELOT'S MONKMAN ACTION
Ocelot, the only independent with a large stake in the play, has been a partner with BP in six wells since April 1990.
It owns interests in 120,735 gross acres and 32,130 net acres in the area and in 852 line miles of seismic. The Grosvenor Park Natural Gas Fund is a drilling fund participant with Ocelot in Monkman projects.
Ivor Bond, exploration vice-president for Ocelot, says the company has "just scratched the surface" of the potential on the acreage it holds.
BP has been operator on the tests, but Bond says Ocelot keeps a close eye on drilling operations.
All of the tests with BP have been gas successes except the last. Wolverine b-30-C was cased to total depth and has been suspended pending further evaluation.
Bond says there were gas shows during drilling, but completion operations failed to produce gas in commercial quantities.
"One of the critical elements of this play is the fracturing. It doesn't look like there's a high degree of fracturing in this well," Bond said.
"You are targeting a narrowly defined seismic target. There is a problem with data there because you are going into faults where the eastern limit is almost vertical and you have a complete loss of data."
Despite the question mark over the b-30-C well, Bond says Ocelot is more than happy with its experience in the Monkman area to date.
Ocelot, which has been working in the region since the early 1970s, says it has identified an additional 10 to 20 potential drilling locations in the area. For the near future, it plans to concentrate on acreage held on its own behalf in the Brazion area and in partnership with BP.
Copyright 1992 Oil & Gas Journal. All Rights Reserved.
