Crucial negative pressure test, on BP blowout well, taking place before our eyes”
A negative pressure test on the BP Blowout Well is more valuable than a positive pressure test.
Déjà vu for the 20th of May 2010
On the 14th of July 2010, I wrote for OPED News the following paragraph:
“Mark Hafle, BP’s senior drilling engineer testified to the MMS on May 28, 2010 that the well had lost integrity and that thousands of barrels of mud had been lost down this well during drilling. This meant that the formation integrity had blown out. Reports at the hearings in May also indicated that the LOW positive pressure tests on the day of the blowout on April 20, 2010 had passed but the negative pressure tests had failed, so the well was not properly sealed. This happened within a few hours of the blowout.
The cement-casing structure is compromised. The well had ballooned out and the formation had blown out, long before the blowout occurred.”
What is a positive pressure test?
That is where the drilling contractor and roughnecks pump drilling mud into the well. This drilling mud fills the hole and by the mud’s density, keeps the oil and gas from the blown out formation from being able to enter into the well. The density of the mud (mudweight) exceeded the pressure of the oil and gas and there appeared to be no loss of mud into the formation, or they said there was no loss or they were not monitoring the loss incorrectly. That test was successful on the day of the blowout. So if you finely balance the pressure of oil and gas coming in against the pressure of drilling mud you are pumping in you get a Static Kill (no movement). On the 4th of August 2010 their static kill was achieved at 13.2 pounds per gallon mudweight. No movement either in or out of oil or mud. If you were to increase the mud density in order to increase the pressure, above the 13.2 pounds per gallon (0.694 pounds per square inch per linear foot increase with depth) or 12742 psi at the bottom of the well (18360 feet), the drilling mud would flow out the well into the formation.
So just before the static kill began, we know that their pressure gauges were reading about 7000 psi. Where is the missing pressure of 5742 psi going? It is not entering the well. It was not measured by their pressure gauges.
A negative pressure test is when you remove the drilling mud and replace it with air or water.
This is what they did on the day of the blowout. They removed the drilling mud and replaced it with water. The casing cement structure did not hold and oil and gas rushed in to cause the blowout.
So the positive test only tells us what pressure we need to maintain in the hole in order to put cement in to seal the well and keep the oil and gas out. That pressure appeared to be 12742 psi. If the mud density had been 17 pounds per gallon while drilling, the pressure would have been 16457 psi at the bottom of the well.
Therefore we had 7000 psi coming into the well before the Static Kill.
12742 psi is not coming in. 5242psi is going somewhere?
Scenario 1
The well is acting like a one way valve, resisting the true outside pressures from entering the well. The holes through the casing and cement must be relatively small. Oil and gas could only come in at 7000 psi, but it requires 12742 psi of mudweight or13.2 pounds per gallon of drilling mud density to achieve a static kill, that is, that pressure to force the oil and gas out into the formation.
On the 5th of August, 2010 cement was pumped in. BP engineers say they have stopped the oil and gas pressure from entering the well.
13. 2 pounds per gallon of mud weight is not a high mud weight. 17 or 18 pounds would be more indicative of a high pressure well.
Was the pressure always this low or has it fallen off over the last 114 days as the oil and gas has been depleted?
Scenario 2
An alternative idea would be that 12742 psi was coming in at the base of the well but that 5742 psi was escaping out into one of the low pressure oil and gas horizons higher up in the well, leading to only 7000 psi being recorded.
I would imagine that this second scenario would be more difficult to seal than the first scenario as more open porous structure would be found.
The pressure gauge does not yet read zero? It reads 4200 psi.
If this well can be easily sealed with cement now, then either BP has bungled their way through the last 114 days or the pressure has dropped drastically to allow the cement to seal this blowout well. BP’S, technical spokesman, Kent Wells says that they have reduced the pressure to 4200 psi in the BP blowout well, with the cement plug in place. He says the casing stack is loosing bubbles, through the capping stack and it is normal as they have been there since the beginning.
They aim to lower the pressure in the casing to about 2750 psi.
Below is a transcript from Wednesday's teleconference press briefing by Admiral Thad Allen, National Incident Commander for the Deepwater Horizon/BP oil spill. August 11, 2010 1:30 p.m. CDT.
Joel Achenbach and Monica Hatcher, two reporters pose questions to Thad Allen. They are very important as far as getting Thad Allen to put on record that he thinks there is no chance of a further blowout and that the cement seal has worked.
Joel Achenbach: Yes Admiral just to get back to something you said a little earlier about there could be stagnate oil in the annulus there and you mentioned something about pushing that, raising the pressure and pushing that up into the blow out preventer.
Can you just clarify that I guess what I’m wondering is there a concern that the going in there you know intercepting the annulus and going in with more cement or mud could somehow back fire I guess and cause a problem?
Thad Allen: Yes good question (Joel), let me I’m not an oil field engineer although I’ve been to school pretty good in the last 100 days and let me see if I can explain this in terms of that I understand it maybe it’ll be useful to you.
The casing in which the drill bit and the well and the well pipe sits (hang) from the top of the well head. And then they kind of telescoped down to the smaller diameters. In that mechanism where they hang off the top of the well head, there was a seal and if enough pressure is applied from the annulus, this is outside the casing, on that seal it is meant to give way so it won’t cause damage to the well bore.
In other words it’s like a relief valve, and the seal which completely circles the casing at the top of the well if enough pressure is exerted will rise up and allow oil to flow. One of the theories was that somehow sometime during the explosion or what happened that that pipe was lifted up to allow that seal to be opened. It might have allowed oil to move up into the blow out preventer, it might have been the source of the hydrocarbons coming up other than the actual casing itself.
We don’t think that’s the case right now we think it’s seated where it should be but what we wouldn’t want to have happen is to start pumping mud and cement into the annulus at the bottom is filled with cement and you have stagnate oil there. And we increase the pressure as we’re doing that so that stagnate oil is forced up and that forces that seal to rise up open itself and go into the blow out preventer.
And as you know we restricted the pressure on the injectivity tests in the top kill to be less than 8,000 psi. The cap itself is rated at 10,000 psi and what we want to understand is we go ahead with the mud and the cement for the bottom kill is there any chance at all that that would force stagnate oil up to the point where it would lift that up again, open those seals, push that up into the blow out preventer and the capping stack and at some point erode, approach pressures that might be a concern to us.
We think it’s a very low probability outcome but the discussion of those seals and whether or not that pipe has ever been lifted is something that’s been discussed for some period of time. But we think we just need to rule it out before we go forward.
Joel Achenbach: Can I just ask that, is that if that did happen the well would still have the cement plug at the bottom so you wouldn’t return to a free flowing gusher with full communication between the reservoir and the Gulf, would you?
Thad Allen: Absolutely correct. There is very little harm to the environment but we need to understand that they would like to have the blow out preventer if they can removed intact.
Monica Hatcher: Yes and the annulus I was just trying to get an idea?
Thad Allen: Yes I’m sorry.
Monica Hatcher: How big that space is.
Thad Allen: Yes not to get too Webster’s Dictionary on you here but the annulus is defined as the difference between two concentric circles. Once circle, a larger circle the difference them, that ring if you will. That is what an annulus is and so we’re talking about the distance between the casing pipe and the well bore. That may vary at different places in the well but we are talking about inches.
Monica Hatcher: OK thank you.
Relief Wells being drilled
Kent Wells, BP’s technical spokesman said on August 11, 2010, that the relief wells will have the mud weight at 13.8 pounds per gallon (0.731 pounds per square inch per linear foot increase with depth) or 13091 psi at near the bottom of the well, the intersection point. (17,909 feet)
There is some concern that the relief wells will pressurize “old oil in the annulus” and break the seal near the blow out preventer. Of more concern should be the worry that this is where the pressurized oil and gas resides and the blown out formations exist. This zone should be the super porous zone that absorbs all the cement and drilling mud and remains very difficult to seal.
My Conclusions
Has BP sealed the well casing or production pipe that did not need sealing? And we are now waiting for them to seal the annulus (the space between the casing and the rock strata) from the actual oil pressure threat, waiting to explode as soon as the cap is removed? Time will tell.
The Controlled oil pressure reading, in the casing, as they gradually depressurize the mud-water- gas mixture is now 4200 psi? That is less than the pressure of sea water, which would have exerted a force of 8228 psi at the bottom of the well. We know the pressure was 7000 psi in the well before the cement plug was put in place. This is the crucial NEGATIVE PRESSURE TEST TAKING PLACE BEFORE OUR EYES. It must have BP on edge as it is this test which led to the blowout. Of course there was no cement plug on April 20, 2010, the day of the blowout. The pressure gauge should eventually read ZERO, when all the gas has been released if the cement seal is in good order. If however there are other breaks in the casing or other horizons of oil and gas at higher levels that are also supplying natural gas pressure, the pressure will fall more slowly and may stabilize at a value above zero psi.
Chris Landau.
August 11, 2010.
Thursday, August 12, 2010
Friday, August 6, 2010
A negative pressure test on the BP blowout well is more valuable than a positive test, by Chris Landau (geologist)
Déjà vu for the 20th of May 2010
On the 14th of July 2010 I wrote for OPED News the following paragraph.
“Mark Hafle, BP’s senior drilling engineer testified to the MMS on May 28, 2010 that the well had lost integrity and that thousands of barrels of mud had been lost down this well during drilling. This meant that the formation integrity had blown out. Reports at the hearings in May also indicated that the LOW positive pressure tests on the day of the blowout on April 20, 2010 had passed but the negative pressure tests had failed, so the well was not properly sealed. This happened within a few hours of the blowout.
The cement-casing structure is compromised. The well had ballooned out and the formation had blown out, long before the blowout occurred.”
Let us understand what a positive test is. That is where they had pumped in drilling mud that was filling the hole and being kept in the hole by the pressure of the oil from the blown out formation trying to get into the well. That test was successful on the day of the blowout. So if you finely balance the pressure of oil and gas coming in against the pressure of drilling mud you are pumping in you get a static kill. On the 4th of August 2010 their static kill was achieved at 13.2 pounds per gallon No movement either in or out of oil or mud. If you were to increase the mud density in order to increase the pressure, above the 13.2 pounds per gallon (0.694 pounds per square inch per linear foot increase with depth) or 12742 psi at the bottom of the well (18360 feet), the drilling mud would flow out the well into the formation.
So just before the static kill began, we know that their pressure gauges were reading about 7000 psi. Where is the missing pressure of 5742 psi going? It is not entering the well.
A negative test is when you remove the drilling mud and replace it with air or water.
This is what they did on the day of the blowout. The casing cement structure did not hold and oil and gas rushed in to cause the blowout.
So the positive test only tells us what pressure we need to maintain in the hole in order to put cement in to seal the well and keep the oil and gas out. That pressure appears now to be 12742 psi. If the mud density had been 17 pounds per gallon, the pressure would have been 16457 psi at the bottom of the well.
Therefore we had 7000 psi coming into the well before the Static Kill.
12742 psi is not coming in. The well is acting like a one way valve, resisting the true outside pressures from entering the well. The holes through the casing and cement must be relatively small.
On the 5th of August cement was pumped in. BP engineers say they have stopped the oil and gas pressure from entering the well. Does the pressure gauge now read zero?
Let us all hope that it is true.
13. 2 pounds per gallon of mud weight is not a high mud weight. 17 or 18 pounds would be more indicative of a high pressure well.
Was the pressure always this low or has it fallen off over the last 105 days as the oil and gas has been depleted?
An alternative idea would be that 12742 psi was coming in at the base of the well but that 5742 psi was escaping out into one of the low pressure oil and gas horizons higher up in the well, leading to only 7000 psi being recorded.
I would imagine that this second scenario would be more difficult to seal than the first scenario as more open porous structure would be found.
If this well can be easily sealed with cement now, then either BP has bungled their way through the last 105 days or the pressure has dropped drastically to allow the cement to seal this blowout well.
WHAT DOES THE PRESSURE GAUGE READ NOW?
Chris Landau
August 6, 2010
chrislandau@yahoo.com
christianjlandau@yahoo.com
On the 14th of July 2010 I wrote for OPED News the following paragraph.
“Mark Hafle, BP’s senior drilling engineer testified to the MMS on May 28, 2010 that the well had lost integrity and that thousands of barrels of mud had been lost down this well during drilling. This meant that the formation integrity had blown out. Reports at the hearings in May also indicated that the LOW positive pressure tests on the day of the blowout on April 20, 2010 had passed but the negative pressure tests had failed, so the well was not properly sealed. This happened within a few hours of the blowout.
The cement-casing structure is compromised. The well had ballooned out and the formation had blown out, long before the blowout occurred.”
Let us understand what a positive test is. That is where they had pumped in drilling mud that was filling the hole and being kept in the hole by the pressure of the oil from the blown out formation trying to get into the well. That test was successful on the day of the blowout. So if you finely balance the pressure of oil and gas coming in against the pressure of drilling mud you are pumping in you get a static kill. On the 4th of August 2010 their static kill was achieved at 13.2 pounds per gallon No movement either in or out of oil or mud. If you were to increase the mud density in order to increase the pressure, above the 13.2 pounds per gallon (0.694 pounds per square inch per linear foot increase with depth) or 12742 psi at the bottom of the well (18360 feet), the drilling mud would flow out the well into the formation.
So just before the static kill began, we know that their pressure gauges were reading about 7000 psi. Where is the missing pressure of 5742 psi going? It is not entering the well.
A negative test is when you remove the drilling mud and replace it with air or water.
This is what they did on the day of the blowout. The casing cement structure did not hold and oil and gas rushed in to cause the blowout.
So the positive test only tells us what pressure we need to maintain in the hole in order to put cement in to seal the well and keep the oil and gas out. That pressure appears now to be 12742 psi. If the mud density had been 17 pounds per gallon, the pressure would have been 16457 psi at the bottom of the well.
Therefore we had 7000 psi coming into the well before the Static Kill.
12742 psi is not coming in. The well is acting like a one way valve, resisting the true outside pressures from entering the well. The holes through the casing and cement must be relatively small.
On the 5th of August cement was pumped in. BP engineers say they have stopped the oil and gas pressure from entering the well. Does the pressure gauge now read zero?
Let us all hope that it is true.
13. 2 pounds per gallon of mud weight is not a high mud weight. 17 or 18 pounds would be more indicative of a high pressure well.
Was the pressure always this low or has it fallen off over the last 105 days as the oil and gas has been depleted?
An alternative idea would be that 12742 psi was coming in at the base of the well but that 5742 psi was escaping out into one of the low pressure oil and gas horizons higher up in the well, leading to only 7000 psi being recorded.
I would imagine that this second scenario would be more difficult to seal than the first scenario as more open porous structure would be found.
If this well can be easily sealed with cement now, then either BP has bungled their way through the last 105 days or the pressure has dropped drastically to allow the cement to seal this blowout well.
WHAT DOES THE PRESSURE GAUGE READ NOW?
Chris Landau
August 6, 2010
chrislandau@yahoo.com
christianjlandau@yahoo.com
Sunday, July 25, 2010
Rigel Well "Leaking" Near BP-Transocean-Halliburton-Anadarko-Mitsui Gusher by Chris Landau (geologist)
Rigel Well "Leaking" Near BP-Transocean-Halliburton-Anadarko-Mitsui Gusher (BPTHAM)
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