In early August, Sunoco resumed drilling for the Dragonpipe (Mariner East pipeline) at the Shoen Road drill site in Exton, PA. This location is at the foot of a long slope that represents one edge of the “Great Valley”, a geological feature that dominates the northwestern suburbs of Philadelphia. The drill path runs uphill to a point near the upper edge of the Great Valley at Devon Drive. Another drill rig is operating there, drilling in the opposite, downhill direction.
As with previous attempts, the drilling is not going well. There is an underground aquifer in the drill path, and when Sunoco drills into it, the downhill drill site immediately floods. That has happened twice before and happened once again in the current attempt.
Here’s a quick review of the history of this drill site.
Drilling, round 1. Drilling at Shoen Road originally began in June 2017 and was abandoned when the aquifer was hit and huge amounts of fresh water began to flood downhill, swamping the drill site. The hole was grouted (plugged) and no more drilling occurred until October 2019.
Many residents uphill from the drill who had private wells lost their water. Sunoco arranged for water to be provided in large plastic tanks called “water buffaloes” and subsequently had to pay for the well owners to be connected to public water.
Despite the grouting, things on the hillside did not return to normal. Springs and seeps began appearing on the hillside in the easement where none had been before. The drilling had somehow opened up new channels for groundwater to reach the surface. That was a troubling sign. The two operating pipelines of the Mariner East system (the 8-inch Mariner East 1 and the 12-inch workaround pipeline, both built in the 1930s) are present in that same easement. The new underground water flows might well be following those pipelines before reaching the surface. They could easily be undermining the soil that supports those pipelines, leaving them vulnerable. Water is still emerging from those seeps.
Drilling, round 2. Sunoco starting drilling again on October 9, 2019, but that attempt was soon abandoned. On October 17, they once again hit the aquifer and had to stop because a local residential well was threatened.
That brings us to the present day.
Drilling, round 3. The new round of drilling is having exactly the same result as the previous rounds: water is flooding back to the drill site. Since Sunoco has paid to have all the nearby local residents on public water, there is no longer an immediate risk to private wells. (It’s unclear what the risk may be to nearby wells owned by Aqua Pennsylvania, the local water utility.)
This time, Sunoco has arranged for huge tank trailers to be brought in so that the water that is pumped out of the drill pit can be carried away. One estimate is that 250,000 gallons a day were being carted off in this way (50 trucks a day at 5,000 gallons each).
On Sunday, August 9, Sunoco resorted to a huge “dewatering system”, consisting of a flat area surrounded by straw bales and lined with plastic sheeting, to which it was diverting water from the overflowing borehole. The water, which was full of drilling mud and other sediment, overflowed into the yard of a nearby apartment complex and from there into a creek. On August 7 the DEP had told West Whiteland Township this system “did not pass muster” and another option was needed and wouldn’t be in place until the next week. Ginny Kerslake and Rep Danielle Friel Otten contacted the DEP and an inspector arrived, initiating an investigation.
We don’t know what effect the drilling is having on the local aquifer, or on the supply of public water from nearby wells owned by the water utility. Will their flow be affected? Will their water quality be affected? Will Sunoco be able to control the flooding at the drill site enough to resume drilling? All of that remains to be seen.
For what it’s worth, Sunoco is apparently denying that the aquifer was hit. A company spokesperson sent the Daily Local News a terse one-sentence statement: “We did not impact the aquifer at Shoen Road.” So was an aquifer hit or not? Those nine carefully chosen words don’t exactly say. If the drill located at Shoen Road hit an aquifer deep in the adjacent hillside, is that aquifer “at Shoen Road”? Was the aquifer “impacted”? This statement sounds like a lawyer must have drafted it.
How do you distinguish a frac-out from ordinary mud? In addition to the water flow-back, drilling mud started to surface on the hillside easement. Since 2017, Sunoco has been under a legal requirement that it must stop drilling when an “inadvertent return” (frac-out) of drilling mud occurs, but in the latest incident they didn’t stop until local residents complained to the authorities.
The police had to be called when workers began acting aggressively toward a landowner who objected to them trespassing on her property as they attempted to contain the frac-out runoff with piles of sandbags.
Sunoco is apparently questioning whether a frac-out even occurred this time. The DEP issued a statement about the testing it would do to settle the question. “To determine whether an IR [inadvertent return, or frac-out] occurred, the Department is following established protocol that considered three criteria: pH, conductivity, and color. These results are still under analysis. Drilling activity remains stopped at this site. If it is determined that an IR occurred, the site will be shut down in accordance with the [legal agreement] and a restart report will be required.”
There is a potential problem with the DEP’s approach: the three criteria it plans to use (pH, conductivity, and color) do not uniquely identify drilling mud. This means Sunoco may be able to claim the mud is not due to drilling. Ginny Kerslake, who is a soil scientist in addition to being the owner of the property in question, wants to see a more definitive test. For bentonite, the primary component of drilling mud, the proper test would be x-ray diffraction. This has been the standard method of determining mineralogy for over 50 years.
What’s next? For now, the future of drilling at Shoen Road is up in the air. On August 10, the drilling rig was shut down, and as of this writing (August 16) it is not operating. Water is still being pumped out of the drill pit. There is no report yet from the DEP on whether drilling mud was identified in the apparent frac-out material.
Don’t forget Safety 7. If you object to what Sunoco is doing to our area, please make a contribution in support of the Safety 7 case before the PUC. This is the single most important thing you can do right now. Expert witnesses are expensive, but they are critical to the case, and more support is needed. Please contribute—whether it is $5 or $500—at the Safety 7 GoFundMe site: https://www.gofundme.com/f/support-the-Safety-7-Halt-Mariner-East