A Chesapeake Energy drilling rig working in Oklahoma hit a shallow pocket of gas on Thursday causing a blowout which burned the rig to the ground. Jim Gipson, Director – Media Relations for Chesapeake, told the media one story but told a concerned Denton citizen a completely different story. Both stories can't be true.
I blogged about the blowout on Friday and there are currently 28 comments on the post. “A Nonny Mouse” an occasional commenter, recalled the Williams blowout in Grandview that contaminated drinking water of three families and poisoned several animals. Last year the landowers settled with Williams and were forced to sign non disclosure agreements.
One Denton resident who is involved with a group making recommendations to beef up Denton's drilling ordinance read that comment and wrote to Chesapeake through their website asking about the possibility of water contamination from the blowout. Gipson wrote her an email answering her question but his answer conflicts with the answer he gave the media.
I will post both answers below. Because this industry is stuck on stupid so we will never know the truth we will have to assume the worst.
Story #1 given to the media:
No injuries or environmental threats were reported, Jim Gipson said in an email.
The rig had spud the Davis 30 12-26 well four miles northwest of Sweetwater in western Oklahoma. It was drilling ahead at 900 feet when it hit a zone of pressurized gas, which quickly flowed back up the well and caught fire.
The well was slated to drill vertically to 12,000 feet before kicking off the lateral.
Operations were at such an early stage that a raft of safety equipment had not been hooked up yet, including the blowout preventer and gas separator.
The equipment had not been installed because crews had not yet set surface casing on the well and the blowout preventer mounts on top of the surface casing, Gipson explained.
“So the weight of drilling mud was the only pressure control,” he said. A well-control crew is on site and another crew is working to salvage the rig, Gipson said. “There will be very thorough investigation into the cause of the incident,” he said.
Story #2 given to concerned citizen (I removed the citizen's email address because it is a private citizen. Mr. Gipson works for CHK so his email address is available through their website)
From: Jim Gipson <firstname.lastname@example.org>
Date: January 7, 2012 3:09:49 PM CST
Subject: Re: Blowout
The water table had already been isolated and sealed off from the well with steel casing and cement.
So I wrote to a petroleum engineer I know to ask what it all means in terms of possible water contamination.
article states the surface casing was not set yet — so this is an open hole blowout — nothing is downhole to protect aquifers, etc
Somewhere near Sweetwater, Oklahoma there is a big, gaping hole directly through the High Plains aquifer. The hole is now full of additive laced drilling mud and the newly released shallow gas .
UPDATE: To respond to “a casual observer” in the comments.
First, let's be precise about the email: “[A] casual observer” call it “an anonymous email.” Words are important and this industry is skilled at manipulating words. It was NOT an anonymous email. It is an email from Jim Gipson, Director – Media Relations, Chesapeake Energy to a private citizen who was concerned about aquifer contamination.
The commentor, “a casual observer,” watched a video online and is now demanding a retraction because the video indicates that Chesapeake might have had a “conductor casing” in place.
I am confident that Chesapeake does not need “a casual observer” to rush to their defense because they employ a team of people for that.
But, let's assume that the well did have a “conductor casing.” I, again, contacted a petroleum engineer to find out what that mgiht mean.
Here is the bottom line from the petroleum engineer:
Clearly conductor casing is for drilling rig support and not for aquifer protection.
Here is some additional informaton about casing from the petroleum engineer:
Conductor casing is installed first, usually prior to the arrival of the drilling rig. The hole for conductor casing is often drilled with a small auger drill, mounted on the back of a truck. Conductor casing is usually no more than 20 to 50 feet long. It is installed to prevent the top of the well from caving in and to help in the process of circulating the drilling fluid up from the bottom of the well. Onshore, this casing is usually 16 to 20 inches in diameter, while offshore casing usually measures 30 to 42 inches. The conductor casing is cemented into place before drilling begins.
Surface casing is the next type of casing to be installed. It can be anywhere from a few hundred to 2,000 feet long, and is smaller in diameter than the conductor casing. When installed, the surface casing fits inside the top of the conductor casing. The primary purpose of surface casing is to protect fresh water deposits near the surface of the well from being contaminated by leaking hydrocarbons or salt water from deeper underground. It also serves as a conduit for drilling mud returning to the surface, and helps protect the drill hole from being damaged during drilling. Surface casing, like conductor casing, is cemented into place. Regulations often dictate the thickness of the cement to be used to ensure that there is little possibility of freshwater contamination.
You can see some diagrams HERE.