All wells encountered oil.https://www.aapg.org/explorer/2011/06jun/bakken0611.cfm
An analog to existing Devonian
Western Montana Bakken in Play
By DAVID BROWN, EXPLORER Correspondent
A significant new Bakken Shale oil play has finally warmed up in northwest Montana.
After a brutal winter that all but stopped move-in and explorationactivities, operators have gone back to work completing their initialtest programs.
The potential play area includes Glacier, Toole, Pondera and Tetoncounties in Montana and extends across the border into Canada, where theBakken equivalent is known as the Exshaw.
Across the state from the North Dakota-Montana Bakken play in theWilliston Basin, the new Alberta Basin exploration area is seen as ananalog to existing Devonian shale oil production.
Play depths range from 4,000 to 7,500 feet in the most activeexploration region, stretching from the western thrustbelt to theSweetgrass Arch on the east.
Estimates of the total resource in place vary from 10 to 15 million barrels of oil equivalent per square mile.
Rosetta Resources Inc., Newfield Exploration Co. and AnschutzExploration Co. dominated early leasing, but more than a dozen smallerU.S. independents and Canadian junior oils have taken neighboringpositions.
“Most of the activity is on the Blackfeet Indian Reservation, whichmakes it a little bit difficult” to get information, said Tom Richmond,division administrator for the Montana Board of Oil and Gas inBillings.
Almost all drilling so far has been vertical, light, and very tightin terms of disclosure, Richmond noted. He said companies have sixmonths from completion before they must begin releasing well results.
Both Newfield and Anschutz have drilled horizontal wells on theMontana side of the Southern Alberta Basin, Richmond said. He describedthe Anschutz well as something of an offset to a much earlier discovery.
“There’s a Greenhorn Shale well that’s been producing just outsideof Glacier National Park for 35 years,” he said.“It’s our only Greenhornwell.”
Testing Continues
Like its eastern counterpart, the Alberta Basin Bakken hasattractive shale oil features. It also offers multiple prospectivezones, including the Nisku, Bakken-Three Forks and Lodgepole formations,as well as other secondary targets.
Good pipeline transportation exists in the area, thanks in part tothe presence of the once prolific Cut Bank oil and gas field in additionto Canadian production.
Operators plan to evaluate the western Bakken play based on theirvertical test or pilot programs. No meaningful production picture willemerge until more wells have been horizontally drilled and fractured.
Rosetta Resources has a 300,000-acre lease position in northwestMontana, where it had two rigs under contract and was completing an11-well vertical drilling program.
At the beginning of April, the company had drilled eight verticaldelineation wells with operations under way on its ninth and tenthvertical wells. An additional vertical well was planned for the secondquarter of 2011.
Based on encouraging results, Rosetta said it also will spud the first of three planned horizontal wells in the second quarter.
Newfield Exploration had drilled seven vertical wells and completedand placed on production two horizontal wells. It announced that all ofits Alberta Bakken wells to date encountered oil.
Newfield has 280,000 net acres in the play in Glacier County.
“We recently completed our second horizontal well and are preparingto drill our eighth vertical well. We continue to test multipleperspective horizons across our acreage,” said Lee Boothby, Newfieldpresident.
“As we have said time and again, we’re executing on our assessmentplans, testing multiple formations,” he added,“and do not plan todiscuss results until we have a better understanding of our acreage andits potential.” 