Published: October 31st, 2012 at 2:04 pm ET
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Texas Brine, Oct 29, 2012 (h/t jec):
[...] During hydrocarbon removal on Friday and Saturday, the casing pressure was reduced thus indicating brine was filling the casing. However, after this work, hydrocarbons continued to enter the casing from the cavern causing the casing surface pressure to return to 940-970 psig on Sunday.
[...] cavern floor had risen an additional 10 feet from the previous measurement on October 19. The cavern floor has come up approximately 52 feet since it was first measured on September 24. [...]
Published: October 31st, 2012 at 2:04 pm ET
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sending...
This is really scary. What is the meaning of this. Note the rather crptic comment in this report from Texas Brine. BET they have a good, very good idea whats what.
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There are three pipes into the cavern, each one inside the other. The inside pipe is the longest and goes down into the cavern brine. The second one goes down to somewhere near the top of the cavern. The third and largest pipe is the casing. It goes to the cavern ceiling.
They're injecting brine in the inside pipe and suck the gas/oil up the second pipe. They monitor the pressure of the casing (third pipe) to make sure they're pushing in as much brine as the oil/gas they're sucking out. Eventually, no more oil and gas is sucked out (just brine) and the cavern pressure drops to around 500 psi measured at the third pipe.
If nothing more leaks into or out of the cavern, the pressure will stay at 500 psi. Instead, stuff leaked into the cavern after they were done. Mud/silt flowed into the 300' diameter cavern from outside – raising the 'floor'. Maybe some more of the west wall or ceiling salt has collapsed as PhilipUpNorth said.
In addition, the outside oil/gas formation pressure outside the salt is around 950 psi. When they stopped pumping out the inside of the cavern, it was only 500 psi or so. So the gas/oil outside squeezed its way inside, raising the pressure to 950 psi. They won't be able to stabilize the cavern at the 'old' plug and abandoned pressure of 550 psi or whatever they used unless they suck the outside oil/gas formation dry.
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Ugh. What is breathing underneath? Sounds like from War Of The Worlds.
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Big move, short time; bad.
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Yes the pressure seems a tad on the high side. I wonder what is raising the floor, oh it's probably just the trees falling into the sinkhole. I wish. I wonder if it is additional pressure? I don't think this is feasible, does anyone know?
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Or, it could be that salt from the top or sides of the cavern has continued to cave into the bottom. I wouldn't worry about this.
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OR based on a little history..maybe in 2010 when Mantle Oil & Gas blew out an oil well they were drilling(BOP failed..gee where have we heard that before?)..fractured the area and allowed gas/crude to migrate…
Yes two years ago..but thats nothing in geologic time..
http://www.dailycomet.com/article/20100814/ARTICLES/100819568
workers trying to cap a blown-out oil well in Assumption Parish, and residents are complaining of an oily stench in the air.
A well operated by Mantle Oil & Gas blew out Wednesday, spewing oil and gas 200 feet into the air. State and local authorities have evacuated six homes.
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Video of the large plume of oil/gas..that was a HUGE amount of pressure..http://www.youtube.com/watch?v=oG36ABVs11c
Mantle Oil and Gas LLC (we see limited liablity company again..note LIMITED) from Texas. Just like Texas Brine, LLC. hum..a theme..??
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The investigation..but no results..
http://loga.la/oil-gas-news/?p=1419
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That is so disgusting that people in the area had to endure such horror! Why wasn't this on the news?! Were those farmers ever compensated? I sure hope they found good lawyers anyway.
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Does this mean the ORIGINAL floor level is uplifting, or material from the top and/or side(s) continues to fall in, thus reducing the depth of the cavern?
I know the report statement sounds straightforward but I think it lacks precise clarity, which seems to be epidemic these days.
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Since its growing at a steady rate it likely UPLIFT. As a fall in from the material from the top would NOT be a foot a day increase in height. More like a uplifting from pressure below..or lack of pressure on top..the floor of the cavern..is it compromised? Whats under the floor? Clay? Anyone got ideas here? Wasn't there a comment by a guru on the danger of the clay not being able to contain the pressure? The reports lack of specifics..and no comments from Shaw Group yet..makes me nervous. Has Chevron said anything recently, other than filing a Force Majure, about their wells? Any reports from other oil/gas companys involved in the salt dome? Silence is deafing..
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But jec, IS IT growing at a "steady rate"?
Who said?
When they measure, it's higher.
Are they measuring at intervals regular enough to say it's rising "X" per day, or week?
Or just x amount since last time?
And will the "additional measurements planned" be said to reveal whether its uplift or debris fall?
I'm just tired of "data" devoid of sufficient content to make it "information".
As I suspect many are.
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The cavern has a fracture in the west wall somewhere around the half-way point. Millions of cubic feet of sand and shale poured INTO the brine-filled cavern and fell to the bottom. The 'floor' of the cavern rose 1700' or so when they first measured it through the new observation well. They're saying it rose an additional 25' in the last month – probably because sand and shale continue to flow in from the fractured west wall.
The 'fracture' is probably more like a ten-foot wide jagged vertical hole 100' high in the middle of the west side. If the wall is not collapsing anymore and the cavern is filled almost to the top of the fracture hole, then you're not going to get much additional fill into the cavern to build up the floor height. That's consistent with what has been happening the last month.
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Pavewaylll – for this, and for your '3-pipes' description above, I again thank you! Your use of language to give visual guide is skilled and works really well at least for my brain!
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The old adage: "You have to make a hole to fill a hole."
Amazing what fracking sludge can do.
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Are the measurements being taken from 1/ fluid level in the sinkhole to the bottom of the cavern or 2/ from a fixed point above ground level ie a satellite?
If taken from the fluid level (boat on sinkhole lowering a probe/sounder) it indicates the bottom of the cavern infilling, presumably with material from the sides/roof, and sloughing.
Only a measurement taken from a fixed point well above the site that ignores the previous RELATIVE data points (surface level of fluid to depth of floor) could indicate uplift.
Presumably the surrounding area would also be uplifting if it were a geological phenomena, so the relationship between the surface level of fluid to depth of floor would not be changing…thoughts?
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This is the measurement taken from the Oxy 3A Observation Well – the second well drilled into the cavern. They're measuring relative to the wellhead at the surface – down through the production string, into the cavern, through the brine and sludge, and up until they hit solid fill inside the cavern. The well casing is cemented from the top of the cavern through the salt to the surface – it can not change length. They're comparing the floor measurement now with where they knew the floor was relative to the original wellhead when the cavern was plugged and abandoned a year or so ago.
The measurement can not be done from outside the salt dome through the sinkhole. The sinkhole is only a few hundred feet deep – the cavern fracture is something like 4500' down. There's sand and sediment in between those two points right up against the salt.
The salt mass moves slowly in geologic timescales – but not in any that would show in human timespans – like the last 50 years. The actual salt at the bottom of the salt cavern would not have moved or changed shape after they completed solution mining. The measured cavern 'floor' got higher every time anything sank to the bottom of the brine-filled cavern.
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thanks Paveway
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