?Eastern North America is blessed with diverse, prospective shale horizons, and these plays have a couple of advantages in lean industry times: They lie close to prime markets and fetch premium wellhead prices. Even as shale drilling falls off in more remote terrains, Eastern plays sustain interest.


A budding play in the Maritimes Basin features the Upper Devonian and Lower Mississippian Horton Bluff shale. Calgary-based Triangle Petroleum Corp. recently announced updates on its drilling program for this emerging Nova Scotia reservoir.


The company is in the midst of completion operations on a three-well program on the 516,000-acre Windsor Block, in the central portion of the province on the southern edge of the Bay of Fundy.
Triangle and its partner, Zodiac Exploration Corp., have earned 57% and 13% working interests, respectively, on the block under a farm-in deal with leaseholder Contact Exploration Inc. Zodiac, also based in Calgary, joined the exploration effort this past summer.


“A lot has happened in the past two years,” says Howard Anderson, Triangle president and chief operating officer.


In 2007, Triangle shot 30 miles of 2-D and 25 square miles of 3-D seismic and drilled two wells on the property. Log analysis of the #1 and #2 Kennetcook wells indicated original gas in place ranging from 89- to 109 billion cubic feet per section. The two initial tests, the only wells drilled on the immense block with the exception of an old dry hole, flowed gas to surface after fracture stimulations and provided sufficient encouragement to expand the exploration effort.


“Our Horton Bluff is just right on the maturity scale: We have total organic carbon contents of around 10%, and we have well above 50% brittle minerals, mostly silica, which means the rock can be fractured.”
Using information from the seismic and subsurface data retrieved by the wells, Triangle received an estimate from reservoir-analysis firm Ryder Scott Co. of 69 trillion cubic feet of gas in place across just 40% of its huge block.


Last year, the company pushed forward and drilled and cased three more vertical tests.


“We’re exploring with verticals, and thinking we’ll exploit with horizontals,” says Anderson. “We need to find the sweet spot both areally and within the land block, and vertically within the shale section.”


High-quality shale has been present in each Triangle test, varying in thickness from 1,000 feet to more than 3,300. The wells span some 14 miles across the northern reaches of the block.


The 8,500-foot N-14-A has been perforated and fractured in four stages with slickwater treatments and is currently flowing back fluid. It intersected a shale and siltstone sequence that was almost a mile thick, and some 3,000 feet of that section delivered strong gas shows during drilling and appeared to be rich in organics.


Triangle’s second 2008 test, O-61-C, was drilled to 9,700 feet total depth at a site some 14 miles west of N-14-A. The Horton Bluff shale reached 1,000 feet in that well, and Triangle has identified five to six zones of interest. It is planning a completion that will evaluate these intervals, which range from deep to shallow and conventional to unconventional.


The third well, E-38-A, was drilled north of N-14-A and also encountered some 3,300 feet of prospective shale. The company is winding up its technical evaluation of the hole and planning its completion strategy.


“We’re looking for the signposts to commerciality,” says Anderson. “We’re not expecting a single ‘Eureka’ moment. It will be a culmination of a number of data points from a number of wells.”


Triangle is tightly focused on Nova Scotia. “Right now, we’ve executed the first half of our C$30-million program,” says Anderson. “Our partner, Zodiac, has decided to stick at 13% working interest, and we’re evaluating new partnerships. We expect to have a new partner on board by the second half of 2009, when drilling will likely resume.”


Like other Eastern shale plays, the Horton Bluff is in its early stages. “We have half a million acres and just five new wells drilled to date. We’ve proved up gas in place, and we think we have a fracturable reservoir. Our current challenge is proving up permeability.”

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