Monday, June 21, 2010

Deepwater Oil Spill - The Admiral on casing and connections, and an update or two

I am following a number of different events this week, and so today is as much a set of updates, as anything. Firstly the oil in the Gulf.
For the first 12 hours on June 21 (midnight to noon), approximately 8,410 barrels of oil were collected and approximately 5,015 barrels of oil and 25.3 million cubic feet of natural gas were flared.

On June 20, total oil recovered was approx. 23,290 barrels:
• approx. 14,570 barrels of oil were collected,
• approx. 8,720 barrels of oil were flared,
and approx. 48.3 million cubic feet of natural gas were flared.

Total recovery was slightly down on June 20 due to shut-ins from a lightning storm in the area of the Enterprise and Q4000 heading changes to accommodate wind shifts.
One of the concerns in the Gulf relates to the arrival of a hurricane, and the National Hurricane Center is showing the development of an area of low pressure that could cause problems later in the week. It has changed from yellow to orange in the past day.

National Hurricane Center

Admiral Allen held a telephone conference call today. In this he mentioned that the deeper relief well has now reached 10,677 ft. They intend sending electrical pulses down the casing of the existing well (WW), which will induce an electro-magnetic field that will help locate it and allow the relief well (RW) to be steered towards it. This will start about now, and will allow a much more accurate estimate of position than they now have. The RW operation is currently scheduled for the second week of August

Given concerns over the integrity of the borehole, Admiral Allen specifically noted (in response to a question from the AP) that during Top Kill they had evaluated the highest pressure that they could use in injecting mud, without impacting the integrity of the casing. When they reached that pressure, without being able to kill the well, then they stopped the operation. But that did not damage the wellbore, and though there may be a problem with the wellbore near the top there is no way to check it, and thus they will rely on the bottom-up filling with mud. This will exert less pressure on the casing, and if, at that time, there is a casing failure it will be with the well full of mud, and thus of less consequence. It is also why they don’t want to cap the well at the surface now. They are capturing the oil and gas, and the RW will be able to perform a safer kill.

Apparently the vents on the top of the LMRP cap are still open, and the 23,000 plus bd that is being produced does not count the amount that is still being vented. However they are bringing in another vessel so that they can tap into the kill line out of the BOP (they are currently only producing through the vent and the choke lines). That will allow an increase in volume collected to a capacity level of 53,000 bd sometime next week.

Following the tests on unbolting with the ROVs the new plan is to unbolt the current cut riser segment and then bolt the new cap onto the top of the BOP. That will then produce through 4,000 ft-long flexible risers (rather than the current rigid pipe) and should be in place by the middle of July. (With a capacity at that time in the 60,000 to 80,000 bd range). This will give the flexibility of totally sealing the end and directing the flow up the risers. BP has been tasked to put instruments that will measure flow into the new cap. The current intent is to carry this change through in the next 7 – 10 days.

He noted that there is no sign of ongoing erosion, and that the BOP is tilting at an angle of 10 - 12 degrees.

In regard to the fielding of the suction barges he said that the Coast Guard had carried out a safety inspection and found some safety issues with electrical grounding, and the barges were kept in port until those had been fixed. Which they now have been, and the barges are being used.

Two different procedures are also now being described for connecting between the RW and the WW. In one option the RW will intersect the well, and break through the rock wall of the well. Then a path will be milled through the casing to inject mud to fill the well, before pumping in cement, at the bottom of the WW to totally kill production.

If there are problems with the connection, and it is not a good intersection, then perforating charges will be used to penetrate between the two wells and provide the pathways for the mud and then the cement. This process also allows the area around the bottom of the RW to be separated from the main well with a packer, if it is needed, as extra protection.

To complete the updates for the evening: The Solar Car race had a slight change in order as they reached the Topeka checkpoint: (The times taken to get there from Broken Arrow are, in hours and minutes)

1) Michigan 7:25
2) Minnesota 7:50
3) Bochum 8:05
4) Calgary 8:41
5) Missouri S&T 9:21
6) Stanford 9:50
7) Koahsiung 10:31
8) New Paltz 11:44
9) Kentucky 12:30
10) Northwestern 13:22

Iowa and Texas-Austin are still in the race. After getting to Topeka the teams rested, and then tomorrow will leave Topeka and head, via Jefferson City, to Rolla, where they will rest on Wednesday evening.

And for those who wonder about the volcanoes in Iceland, the areas of concern are, at least for the last few days, relatively quiescent.

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