Wednesday, July 14, 2010

Warning to BP: Stop the Relief Wells Or a Much Larger Catastrophe is Looming!

I issue a serious warning to BP: Stop it right now, do NOT drill the last few feet of the relief wells. Do NOT punch that hole through. Think it through very carefully! If you proceed to puncture that hole through to the original well, it opens up a Pandora's Box which could lead to a much bigger catastrophe than you have ever bargained for!

BP must pause now and invite all experts for a good debate on exactly what could happen. Build a physical model and test on it. It's foolhardy for BP to just proceed and gamble for a success. Because the worst that could happen is not just another failure, but rather a much bigger catastrophe.

BP explains how a relief well works. Basically you drill another well which intercept and punch through to the casing of the original well, at a point 18000 feet deep, or 135,000 feet below the sea floor. Then heavy mud is injected through the relief well to near the bottom of the original well. The mud will then fill up the original well. Since the density of the mud is heavy it counters the pressure of the oil and gas in the original well, hence stops the flow. Once the flow is stopped the well can be sealed off using cement.

It sounds simple. But due the the extreme depth of the well and the extreme pressure from the reservoir, a lot of technical details makes the plan virtually impossible to work. It could actually cause a catastrophe instead.

There are two possible catastrophes: One is the mud either gets blown out of the blwout well diluted by the oil and gas, or continuously seep down into the underground rock formation, hence wasted. When enough mud is wasted and BP has no more mud at hand, the oil and gas will browing out and explode at the rigs that is drilling the relief wells.

A much bigger catastrophe would be if BP has too much mud, and the mud keeps seeping into the underground rock formation. It damages the rock formation and eventually cracks the sea floor, leading a catastrophic release of gas and oil which is impossible to contain. That is a dooms day scenary.

Under the scenary that Matthew Simmons and many others have discussed, i.e., if the well casing has been damaged or the rock formation at the bottom of the well is already damaged, then relief well will not work. I will not repeat that technical discussion. I will discuss under the best scenary we can hope for, the casing is intact, and show that why the relief well will not work.

The intercept point at 18,000 feet below is not exactly at the bottom of the original well, but some where above the bottom. There will be two flow of materials meeting at the intercept point, and three possible paths where the flows can go: There is the flow of heavy mud from the relief well, and oil and gas up from the underround reservoir. The three paths are either back up into the relief well; going up through the original well; or going down back into the reservoir and rock formation.

It all depends on the balance of pressure, and how fast BP can pump the mud down.

The path of least resistance is up through the original blowout well. Both the oil and gas, and now mixed with the mud, will continue to gush out of the blowout well.

The flow out of the blowout well will only stop if the material within the blowout well is replaced with mostly mud, injected at interception point through the relief well, and that the mud column is heavy enough to generate a counter pressure which matches the pressure at the interception point.

To be able to inject mud into the interception point through the relief well, the mud column plus the pumping pressure must be able to generate a pressure, at the interception point, far bigger than the pressure from the underground reservoir. If the pressure is merely equal to the pressure of oil and gas at the junction point, then only a portion of the mud will enter the junction point and come out of the blowout well together with oil and gas. In such case, the mixture ratio depends on the opening of the hole, and the cross-section of the well casing of the well. For example if the hole is 7 inch in diameter and the well casing is also 7 inch in diameter, you will get a 50/50 mix of mud and oil/gas. The mud is thus diluted and won't be able to generate enough counter weight to stop the flow.

Let's call the pressure in the oil/gas reservoir P0. Now consider the junction point pressure generated by oil/gas flow from the reservoir. First there is a free flowing pressure, let's call it P2. Then, once the flow from below stops, there is a static pressure P1. Please note, P1 >> P2. That's because for the oil to seep through the cracks in the rocks to enter the well and gush out, it takes certain amount of pressure to overcome the resistance. The pressure it takes to push oil through the rock formation equals to the difference (P1-P2).

Now when the mud fills up the relief well and gets injected into the junction point, there are two pressures of the mud at the junction point. There is a static pressure Pa, when the mud is not flowing. There is also a free flowing pressure Pb, when the mud gushes into the blowout well to fill up the well and push the oil/gas out, replacing it with the mud. Please note, Pa >> Pb. When the mud is freely flowing, part of the pressure is needed to overcome the resistance and push the mud through at high rate. The extra pressure it takes to push the mud through into the blowout well equals to (Pa - Pb).

For both the mud and oil/gas flow, the statis pressure (when it is not flowing) is always much higher than the free flowing pressure. When it's flowing, part of the pressure is lost along the path, to overcome the resistance.

We need to guarantee that Pb >= P1, because the mud flow must stop the flow of oil/gas from underground, so it must be higher than the static pressure from the underground source.

But at the same time, we also need to make sure that the mud does not flow down into the rock formation, because that will damage the rock formation and eventually depleting the mud. That means while the mud finally stops flowing, it does not exceed the static pressure from the underground source: Pa <= P1

Such requirements are impossible to obtain. We have:

1.Pa >> Pb
2.Pb >= P1
3.Pa <= P1

All three conditions can not be meet at the same time. It's logically impossible.

But then they do not need to be meet at the same time. Condition 1 and 2 are required while the mud is being pumped into the relief well. But condition 3 can be meet while the mud pump is shut down, so we can reduce the pressure Pa by the pump pressure, Pp. The three conditions are re-written like this:

1.Pa >> Pb
2.Pb >= P1
3.(Pa-Pp) <= P1

Still consider the pump pressure Pp is only 1000 PSI, less than 1% of the typical junction pressure P1 or P2. There is no way BP can do it. They will end up having a mud not heavy enough to satisfy condition 1 and 2, hence fail to fill the blowout well with the mud. or they may have a mud that too heavy to satisfy condition 3, causing the mud to continously seep into the rock formations, cracking the rock formation and eventually deplete all available mud, at which point all bets are off.

More over, the more sticky the mud is, the higher the value (Pa -Pb) will be, and the harder to meet all three conditions.

I predict that BP's relief wells are not going to be successful.

A MORE SERIOUS warning to BP: If the relief wells fail as I predicted, do NOT resort to the desperate act of using nuclear options. If you use nuclear option, there is a good possibility it will trigger chain reaction of methane eruption on a global scale, wiping out virtually ALL LIFE on earth!!! ... is-Looming!

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