By Dr. Jay Lehr
Admit it, you have no clue. Of course we have all seen the diagrams of Shale Gas Wells with the pipe going vertically down into the ground and then turning a right angle to proceed horizontally where the well will be hydraulically fractured (not Fracked). How is that possible? Can you think of any mechanism underground where pipe could turn ninety degrees and keep the end of the pipe, where the drill bit is spinning 360 degrees, to continue penetrating the rock encountered? Of course you can’t, because it cannot be done. Yet amazingly, surely 90 percent of all folks even remotely interested in the topic of shale gas development do not question the possibility of this impossibility. So read on, this well kept secret will be unveiled.
Just over a decade ago, America’s energy out look was revolutionized by technological advances in hydraulic fracturing which has been turned into the slang word Fracking, purposely and cleverly by those who wish to eliminate it from the tool box of US energy development. Hydraulic fracturing is fairly self-explanatory. It accurately conveys the idea that a fluid under pressure is used to break or fracture rock. Most people are familiar with the concepts of hydraulics used to do all kinds of work in cars and machinery. I split wood to heat my house with pressure applied to a blade by hydraulic hoses.
The word Fracking effectively conjures up negative thoughts. It sounds ugly, even a slur on a swear word, maybe even a chain saw massacre movie. If you are inclined to ever talk about the subject, help us fight back by using the words “hydraulic fracturing” and explaining to people who use the term fracking, what they are really talking about. But let’s continue on to how we drill horizontally.
Hydraulic fracturing involves the injection of high-pressure water, to create fractures, along with sand to keep the fractures open, and chemicals to eliminate biological growth that might clog the fractures. All of this then allows natural gas and oil in the rock to be released into the horizontal drill hole and travel under natural pressure up to the surface of the ground where it is collected. It has been done in vertical wells since 1947.
Hydraulically fracturing vertical wells, however, was limited in its value to increase flow of oil and gas by the fact that the vertical thickness of most layers of rock containing oil and gas are only a few hundred feet thick. In 1998, the engineer and businessman George Mitchell recognized that steel pipe could be guided from a vertical plane to a horizontal plane using a flexible drill bit controlled by an internal Global Positioning System.
Those who abhor our use of fossil fuel rest part of their objection to horizontal drilling on their claim that it will pollute our ground water. This would require leakage of the oil and gas through the rock and soil overlying the horizontal pipes harvesting the oil and gas. Here is where the reality defeats the false diagrams of a drilled shale gas well turning at a right angle at any depth the driller might choose. As previously stated, this is impossible.
What they, and likely you, fail to understand is that optimal horizontal fracturing, can only be carried out at great depths. A steel drill pipe will only bend about three degrees per hundred feet of length. It therefore takes thirty 100 ft lengths to bend 90 degrees, bringing the drill bit to a minimum of 3000 below ground before the drilling is actually done horizontally and hydraulic fracturing can begin. From there the well can extend outward for thousands of feet, often reaching out as far as two miles (10,560 feet). Now where hydraulically fracturing a vertical well yielded gas and oil from only a few hundred feet of rock, now the shale gas wells can tap the source formation over more than 100 times a greater length.
Thus the risk of oil and natural gas escaping thousands of feet up to groundwater drinking water sources is infinitesimal. Additionally the vertical portion of the hole that ultimately brings the fossil fuel to the surface commonly has as many as seven layers of telescoping casing.
Now as Paul Harvey used to say, “you know the rest of the story.”