The company yesterday said Questar reported on February 26 that it had encountered major gas flows from its Trail 13C-15J well in the Vermillion area of the Greater Green River Basin.

The well is about 80km southeast of Fall River’s Baxter acreage.

“The sedimentary sequence is essentially the same in both the Greens Canyon (Fall River’s joint venture acreage) and Vermillion areas (Questar’s acreage),” it said.

Trail 13C-15J reached total depth of 13,700 feet (4175.7m) on January 28 before fracture stimulation of the Baxter Shale and Frontier Formation was undertaken.

Fall River said the well began flowing sales gas on February 15 at an initial rate of 4 million cubic feet per day through a 12/64-inch choke. As of February 26, it was flowing at 9MMcfd through a 16/64-inch choke.

Production for the first 11 days exceeded 65MMcf of gas.

Fall River said Questar has no previous experience of such high initial production rates from its previous wells in the area.

Because of this, the company finds it difficult to predict likely decline rates or ultimate recovery, although it anticipates significant fall-off of the production rate once the fracture network depletes, it said.

However, it said Questar has noted that “the early performance of this well does demonstrate the potential significant effect that natural fractures can have on initial production rate”.

“Fall River believes this well demonstrates the upside potential of ‘sweet spots’ in the Basin, including their Greens Canyon acreage, from, it would appear, the presence of open fractures within the Baxter Shale section,” the company said.

“Such sweet spots could potentially have a significant effect on Baxter Shale production economics were they widespread, but the occurrence of such zones is currently unpredictable.”