Marcellus & Utica shales are much deeper to the east and south

Essay by S. Tom Bond, Retired Chemistry Professor & Resident Farmer, Lewis County, WV, February 10, 2019

Some friends and I were at lunch the other day when the subject of a fracking well near the Beaver Run Reservoir “connecting” to older shallower wells came up. This occurred in Westmoreland County, PA, a few miles southeast of Pittsburgh. What had happened, the well pressure in the new Utica well dropped suddenly and the pressure in four older surrounding “conventional” wells rose. (The older wells were vertical and did not reach the depth of the well being drilled.)

The new well is located, rather carelessly, beside the reservoir, which provides water for something like 150,00 people. The worry was that fluids would come all the way to the surface and fracking chemicals would get in the reservoir. Also, explosions or fires could occur at the older wells.

One of our group pointed out that the representations you see in publications show the shale layers like a wedding cake, uniform thickness, parallel and horizontal, which is not an accurate representation. Shale layers are certainly not uniform and not without defects, fractures or fissures.

The deposition of shale is what is described as “turbidites,” a mass of saturated clay mud slipping and slowly being washed down slope in quiet water, well below the surface of an inland sea. It is like a river delta, streams meandering and frequently changing course. This is occasionally being pushed out by slides of coarser sediment deposited nearer shore. This mud contains a few percent of organic matter from sea life, which decays without contact with oxygen to become oil and gas.

The amount of oil and gas is so small and the shale so fine it cannot flow like conventional wells. Fracking breaks some of the shale to release 7% or less of the oil and/or gas present in the shale. Lots of irregularities are present, so the fracturing is not symetrical.

One of us suggested the layer cake model was the result of the confusion between the executives who describe for the artists what they want. Another thought the confusion was between the geologists and the executives, since the executives are “doers” and don’t have much of an education in geology. Every effort is made to keep things simple in presenting information to the public, too. Probably there is enough blame for the misrepresentation to go around to all these sources.

We agreed that ”communication” through the geologic layers is not new. That is, gas having enough pressure to penetrate horizontally (and perhaps vertically) outside the intended boundaries. I recalled discussion with friends in Doddridge County of how some conventional well owners were beneficiaries of fracking, it improved the production of their shallow wells! That was years ago and continues.

Someone over there pointed out to me an abandoned old well that was frosted over from the fracked well gas that had leaked into it. We all knew that gas under pressure cooled when the pressure was relieved. In that case, enough to cause frost in summer, even. Others of our lunch group could tell related stories.

Leaks from around casing not properly sealed is likely the cause of most leaks that destroy well and surface waters. Drillers are impatient to start after the cement is placed around the pipe designed to protect surface water, it costs them hundreds of dollars an hour to have an idle rig. So pressure comes on before the cement is fully set up. They have been known to supply clean water to people near their rig, acknowledging fault. It is usually stopped when the driller leaves the neighborhood, though.

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See also: Geologic Misconceptions: “Layer-cake” stratigraphy | WIRED

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See also: New Penna. Utica Well Being Plugged After Disturbing Other Wells, www.FrackCheckWV.net