A state recommendation to use directional drilling on the top of the Roan Plateau is probably not practical, according to a U.S. Bureau of Land Management document.

The BLM’s reasonable foreseeable development study for the plateau concludes that the technique is “infeasible” on the top of the plateau.

The state Department of Natural Resources recently recommended limiting drilling density to one surface well pad per 160 acres on the top of the plateau, with directional drilling used to reach more gas reserves.

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That plan would result in about 275 well pads on the surface, with 4,400 subsurface wells needed to fully tap the underlying reserves.

The BLM study concludes that it would be feasible to develop 500 natural gas wells on top of the Roan Plateau (see story, page 1). Average well pad spacing would be one per 125 acres.

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Directional drilling has gained favor because multiple wells are drilled from one pad, reducing surface impacts.

In its recommendations to the BLM, the state cited recent advances in directional drilling technology as a reason to look to the same approach for drilling on the plateau top, which environmentalists and local communities say merits extra protection from drilling impacts.

However, the BLM says the extra 3,000 feet of earth that would have to be drilled through to get to gas reserves from the top of the plateau “would make directional drilling infeasible.”

The problem is that the underlying Wasatch geological formation is characterized by wet clay that makes drilling more difficult. Experiences to date on the plateau top have shown drilling through Wasatch took seven times longer than in lower, surrounding terrain.

Exploration activity on the plateau top would be limited to one suitable access road, a weather drilling window of only five months per year, and an estimated availability of five drilling rigs at any one time, the document concludes.

All of these factors create less favorable well economics and fewer wells compared to lower, surrounding terrain, and also make it likely that energy development on the plateau top would occur after much of the surrounding land is developed, the document states.

Greg Schnacke, executive director of the Colorado Oil and Gas Association, also has raised questions about how effective directional drilling would be on the plateau top.

The Roan Plateau Planning Area considered in the reasonable foreseeable development study totals 127,000 acres, of which about 73,600 contain federal minerals available for oil and gas development. Of that, about 18,000 acres are currently leased.

The top of the plateau is almost 54,000 acres in size, with about two-thirds of it being federal land, and the rest private.

The BLM’s reasonable foreseeable development study says the planning area would reasonably sustain a total of 3,460 wells – almost 2,000 of them on federal land and the rest on private – if unconstrained by factors such as concerns about minimizing surface impacts. On the top of the plateau, this would include 335 federal wells and 172 private ones.

The study estimates that the planning area contains 38 percent of Colorado’s total gas reserves of 10.4 trillion cubic feet, and 2 percent of the nation’s total reserves.