Those of us who went to any of Sunoco/ETP’s public presentations know what a show they made of the innocuous nature of drilling fluid. It is composed almost entirely of bentonite clay and water and is routinely used for drilling water wells. Sunoco/ETP will tell you that you could consume it—if you could face drinking mud—and not be harmed.
That is probably true, and yet it does not prove that drilling fluid is harmless. The problem is not what happens when drilling fluid is consumed. The problem is that drilling fluid can do unexpected things underground.
Problems at Chester Creek. This problem was already evident shortly after drilling began at the very first drill site in our area: Judy Way in Aston, PA. The drilling of the pilot hole had only gone a few hundred feet when, on May 11 and 12, drilling fluid started welling up in people’s lawns on Chester Creek Road (in Brookhaven) and in the bed of Chester Creek itself. Drilling was stopped for a time. But when it resumed, on June 25, a new outflow of drilling fluid occurred in Chester Creek.
This photo shows the sandbags Sunoco used to retain the drilling fluid that surfaced in front of two homes along Chester Creek Road.
This incident is instructive because it shows how drilling fluid can flow uncontrollably underground. In a public meeting, Sunoco/ETP reported that the drill was about 50 feet below ground level when the fluid emerged. And the locations where it surfaced were about 100 feet laterally from the intended route of the pipeline. (The fluid emerged in Brookhaven Borough, no part of which is actually on the pipeline route.) Clearly, the drilling fluid had travelled far from the location of the drill bit.
Drilling fluid is pumped through the drill pipe, and it serves as a lubricant for the drill bit. In addition, its fluid pressure is used to turn the drill bit and to re-direct drilling when the bit strays from the intended route. Normally, the fluid flows back up along the drill hole to the drill site, where it is collected in a pit at the point where the drill enters the ground. It is pumped from the pit and filtered to remove rock chips and other bits of debris, and then the fluid is used again.
Drilling fluid does not necessarily go where it is supposed to. But nothing forces the fluid to return along the hole if there are other places it can go. The pressure of the drilling fluid also causes it to flow into any available cracks and gaps that the drill bit encounters. The pressure of the fluid can itself cause the rock to fracture. (In drilling industry jargon, the name for this is a “frac-out”.) If the cracks lead to the surface, the fluid will emerge there. ETP refers to this situation by the euphemism “inadvertent return”. That really means “uncontrolled release” or “frac-out”.
If the cracks in the rock lead to the water table, the fluid will emerge in wells, streams, and wetlands. If the cracks lead to a sizeable cavern, drilling becomes impossible because all the fluid simply disappears into the cavern.
What can a driller do when faced with drilling fluid flowing in unexpected directions? The only two solutions I’ve read about are to back out the drill part way and resume drilling in a slightly different direction, in hopes that the new route will avoid the problem area; or else to inject “grout” (e.g. plaster or something similar) into the area where drilling is occurring, to fill in the cracks
It is not yet clear, to me at least, how the problem at Chester Creek will be circumvented.
An Ohio spill that was really a “frac-out”. In looking at the problems at Chester Creek, I am reminded of the “spill” of about 2 million gallons (!) of drilling fluid that recently devastated a wetlands area in Stark County, Ohio, on April 13—a few weeks before the Judy Way/Chester Creek event. The same company that is building the Dragonpipe, Energy Transfer Partners, was responsible for that problem, which occurred during horizontal drilling for the “Rover” natural gas pipeline. The Ohio event wasn’t a “spill” in the usual sense (a pipe failure or a valve left open in error). It was also an “inadvertent return” (frac-out) in which the company failed to notice until far too late that a vast amount of drilling fluid was surfacing.
ETP had exactly the same problem on a different section of the Rover pipeline (in Richland County, Ohio) on the very next day. There was an “inadvertent return” of 50,000 gallons of drilling fluid.
Two more frac-outs from Dragonpipe drilling. And now we learn that another “inadvertent return” from Dragonpipe drilling happened in Upper Uwchlan Township, north of Exton, on June 17, followed by another (on a different stretch of Chester Creek, behind the Tunbridge Apartments in Middletown Township) on July 17.
The lesson from the Ohio wetlands incident is that drilling fluid, while non-toxic in small amounts, can still do a lot of damage in bulk. And an additional lesson, from Ohio and from our local problems, is that horizontal directional drilling is an imperfect technology. Even when used exactly as intended, horizontal drilling technology can produce massive environmental damage, and there is no way to anticipate where or when it will occur.
Where’s the DEP when we need them?
Updated July 17, 2017 with latest drilling fluid release information.
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