Liard and the Besa River shale

Aug. 20, 2012
Northern Canada’s lesser-explored basins leave lots of scope for big plays, including in thick sections of Devonian-age sediments.

Northern Canada’s lesser-explored basins leave lots of scope for big plays, including in thick sections of Devonian-age sediments.

First came the gas-prone Muskwa and Evie shales in the Horn River basin. More recently the Lower Besa River shales in the Liard basin have emerged.

Houston-based independent Apache Corp., which has aggregated a large acreage position, calls the Lower Besa River first black shale “the best unconventional gas reservoir evaluated in North America with excellent vertical and lateral reservoir continuity.”

The reservoir

Most reservoir properties of the Lower Besa River first black shale compare favorably with those of the Marcellus and Haynesville shales, Apache told investors in June.

In the Besa River, original natural gas in place is 170-500 bcf/sq mile, and Apache said it has identified 48 tcf of dry sales gas from 210 tcf of net gas in place on its acreage (OGJ Online, June 14, 2012).

The shale is 400-1,000 ft thick lying at depths of 9,500-15,000 ft. Porosity range is 3-8%, and water saturation is 15-20%. Total organic carbon values are 3-6 wt %.

The Besa River has excellent vertical and lateral reservoir continuity with continuous gas-filled porosity, the company said.

Besa River is 1,024 ft, 708 ft, and 425 ft thick in three wells Apache drilled in Northeast British Columbia within 40 miles of the Northwest Territories provincial boundary.

Apache showed a development model that would involve recovery of 54 tcf of raw gas using 731 well locations on 61 pads with two drilling rigs per pad.

The Liard basin is mostly in Northeast British Columbia and lies west of the Horn River basin.

The Besa River shale has produced gas in Beaver River field 150 km northwest of Fort Nelson, BC, and northwest of Apache’s early wells (OGJ Online, Oct. 14, 2008).

Transeuro Energy Corp., Calgary, operates Beaver River field, where three vertical wells averaged a combined 1.9 MMcfd in July from conventional Devonian Nahanni carbonates and shallower Upper and Lower Besa River shales (OGJ Online, Apr. 27, 2011). In time Transeuro will frac the shales.

Nexen Inc., which is being acquired by CNOOC Ltd., and Paramount Resources Ltd. both have extensive acreage in Liard.

Apache’s wells

Apache said the D-34-K well, one of three it has drilled and hooked to a pipeline, is believed to be the world’s highest-flowing shale gas resource test.

D-34-K flowed 21.3 MMcfd on a 30-day initial potential test from a 2,900-ft lateral at 12,600 ft true vertical depth after six frac stages. Cumulative production was 3.1 bcf in 12 months, and the company looks for estimated ultimate recovery of 17.9 bcf of gas.

The company’s vertical C-86-F well went to 15,000 ft and had a 30-day initial potential of 9.8 MMcfd, and the vertical D-28-B well went to 13,200 ft and flowed 4.6 MMcfd. The two vertical wells had only a single frac apiece. Net pay thickness is 1,024 ft at C-86-F and 708 ft at D-28-B.

In its development model, Apache envisions drilling horizontal wells with 7,050-8,040-ft laterals with 18 fracs per lateral. The company estimates 400 ft spacing between fracs and 600 m between wells. Drilling time is 110-120 days/well.

The company plans to drill tenure wells in this year’s second half followed by more concept wells in 2013.

Apache’s position

Apache said it would expect to market the Liard basin gas in North America and exports as LNG to the Asia-Pacific region, presumably via Kitimat, BC, as early as 2016.

The company controls 430,000 acres of 100% working interest land in the play. The acreage has access to the TransCanada and Spectra gas pipelines.

Apache, which also has a large position in the Horn River basin, didn’t say how expeditiously it would gear up to pursue the Besa River play.