I’ve been thinking about the blowout Chesapeake Energy caused near Sweetwater, Oklahoma and I have a two questions:
What was that shallow gas pocket doing at 900′?
How did the shallow gas pocket get there?
I’ve been poking around on the Oklahoma Corporation Commission and they don’t have–or I haven’t found it–a map showing the locations of all the oil and gas wells in Oklahoma. So, I resorted to Google maps.
If you move this map to the Northwest of Sweetwater, where the blowout took place, you will find the familiar patchwork of wells. There are a lot of wells in that area so–most likely–there is a lot of fracking going on in the area.
We know that gas migrates. Sometimes it migrates due to crappy casing jobs. But, I recently talked to a very smart guy who pointed out that cement won’t make a secure bond to the materials downhole. GOOD POINT!!! There will always be gaps–even microscopic gaps–and pathways for the gas to migrate between the materials downhole and the casing. Also, remember that they don’t case the entire length of the drill pipe.
We also need to remember that THIS can and does happen.
I can’t find where there is a shallow gas formation in Oklahoma in the area around Sweetwater. Maybe there is but I can’t find it.
So, you tell me: How did that shallow gas pocket get there?
Obviously, CHK was not expecting to hit a pocket of shallow gas.
I talked to another really smart person who said they are fracking and “gas is going everywhere and some of it just happens to go up the casing and into the pipeline.”
My previous postings on this blowout are HERE and HERE. The second link leads to EARTHblog where there are some interesting comments.
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If you have the identification information for the well that blew out, I have an idea about a map..I suspect all the offsets are CHK wells.
Your friend is pondering what many others (including CHK, I hope?) are working through. With as many wells as are in the area IF a gas trap existed, even in isolated “pockets” CHK would know this & would not have been caught with their mud weight down going through the interval. Which seems to me means they need to suspected a casing leak below their surface casing in one of the offset wells & is a reasonable thing to determine.
Base of treatable water @ Sweetwater is about 540′. Not to be a downer here but, I also suspect the casing leak in whatever well has charged up that 900′ interval, is below the treatable water table and SHOULD NOT have impacted the fresh water in the area. I do believe ALL wells in the immediate are should be tested & which ever one(s) is(are) found to be leaking fixed. I would suspect CHK would also want the well(s) fixed so, they can sell that gas instead of injecting it away through a casing leak.
It looks like the well is the Davis #1H in section 30 Twp-12N Rge-26E.
I must clarify myself about fresh water impact..That was in relation to whichever well(s) are leaking @ 900′ ..It sounds like the well that blew out would have been open to the fresh water interval until at which time they got the well plugged & abandoned. Usually, they plug the hole below the fresh water, allow the fresh water to flow back for cleanup and then, isolate the fresh water from the remaining wellbore above.
Mike H. says
More news on “Oops!” well moments:
Pennsylvania DEP fines Talisman for gas well-control incident
“Equipment failure during fracing on Jan. 17 caused about 21,000 gal of hydraulic fracturing fluid and sand to be released for about 3 hr,” DEP North-central Regional Director Nels Taber said.
I’m glad this wasn’t close to homes:
Casing cement issues at a PA well:
Darth Loki says
They are acting like they forgot where the asteroid impact craters are.
They are drilling on the inside edge of an impact crater.
35.250,-100.800 Jeanne d”Arc 101 miles in diameter
Visible Surface Features, Circled by oil and gas wells. >85%
Download:Granite Wash Play Texas And Oklahoma
Texas Data : like The Granite Wash Map Showing Jeanne d’Arc Crater outlined by oil and gas wells.
Think of the crater as upside down Bundt cake. The crater edge is fractured rock forming an underground bowl which is weakly connected to the surrounding rock strata. Pressurize it and then play whack a leak, because the leaks can travel for miles in and through rock debris and impact melt. You will notice few if any wells drilled into the center. Depending on when it hit, say around 370 or so, million years ago, you might find igneous rock in the center uplift. A crater this size is usually a complex crater with an an uplift and maybe a ring. I don’t remember seeing very many wells drilled into the center of the crater. Most of the wells drilled into the center were pre-2005 according to the Granite Wash Map.
Granite wash, impact breccia, same difference. Some of that new fangled Granite Karst topography? Teaching geologists how not to see the obvious.
This is fascinating. I am convinced the shallow pocket of gas came from another well with a leaky casing. All gas wells will leak. But this theory would certainly make for easy pathways.
Darth Loki says
Most of the old craters are still buried under thousands of feet of sediment. But the strata tends to be messed up by faulting since the crater is still settling after those layers have been lain down.
Outside the Meeker you might encounter a few layers with water.
If you drill into the faulted zone along the edge you can have water in most of the strata.
On the other hand, if you pick your spot right (know about the crater being there) you can find areas where the fracture lines pull from lots of pay zones and the permeability is good.
I roughly (and conservatively) estimate that 30 % of the land area in Oklahoma has impact craters that are younger then 310 million years. Statistically 100% of the planet has been hit, but I am referring to structures that are still geologically relevant to oil and earthquake production.