Deepwater Oil Spill - Fishing and Quecreek equipment

There has not been a lot of visible progress at the Deepwater site today. As might be anticipated when BP are trying to extract the three segments of pipe that Admiral Allen commented had been found above the Blowout Preventer (BOP) and in the rams.

To tell you what we found there, there are basically three sections of pipe. There was a section of pipe that is suspended in the middle on the center line that we believe goes down below the blowout preventer into the well some distance. There is a shorter piece of pipe that is sitting beside that pipe in the blowout preventer that was broken or cut about the length of the blowout preventer itself. And then there's a very small piece of pipe laying crosswise.

We believe these pipes are where they're at as a result of the diamond wire cut that we attempted on the riser pipe and then the final shear cut that we did. And we know which cuts were where, because one pipe has a very clean cut, indicating that – that was cut by the diamond wire saw. And the other one is compressed and cut, which would indicate that was cut by the shears that we used.

So we have a good idea of where the pipes are at and where they're located. We're now conducting diagnostics inside the BOP and the capping stack to ascertain the best way to remove the pipes.

Given the need for the procedures to be conceived, written up, approved and then followed, it may be a little time before the pipe segments get removed. This is particularly true if the ram closures that I noted in the last post have yet to be fixed.

The Admiral does not seem concerned with the possibility that if they get hold of the long length of drill pipe that is held in the grip of the rams in the BOP that it will shear when the holding rams are released. This suggests perhaps that they may know (from the scans made of the BOP back near the beginning of this episode) what the pipe looks like, and do not expect that it has been materially cut by the shear blades. (Since it is that cut that would be needed as a starting crack, to help initiate separation of the pipe at the cut, and since it has not failed yet, they may assume that it has sufficient integrity to hold up during the removal process).

Nevertheless he is not concerned that if the pipe were to fall down the well, that it would do much damage to the cement plug at the bottom of the well. He was asked that specific question at the press conference, and replied:

I don't believe so. (It'll fall down) into the well to the extent that it could, and as long as it wasn't protruding above the wellhead, would actually not become an obstacle to removing the blowout preventer. But I think, for forensic purposes, they would like to have that pipe so they can examine it.

He does not, thus, anticipate that it would do much damage to the bottom of the well, even if it fell and hit the top of the cement plug, given its length and that it is surrounded by the production casing and, over an unknown length, by an external cement liner filling the annulus to the surrounding rock.

At present the down-hole camera is not working, the stack seems to have been left open with the BOA Sub C Rov1 monitoring it to see if there are any returns, and the drill rod is swinging freely in the water.

Screen capture from ROV1

In regard to the situation of the Chilean miners, a special drill is being brought to the site from elsewhere in Chile, and in fact may be there by now. The drill that will be used is likely of this size:

Drill bit used at Quecreek

The picture is from the Quecreek rescue operation. However that was a relatively shallow coal mine, with softer rock, and so they are apparently going to use a bit with polycrystalline diamond compact teeth which will allow them to cut through the harder rock. The penetration rate is expected to be about 65 ft a day, though some of the rock from the video shown of the existing borehole passage, seemed to be broken, and that will make drilling that much more difficult.

The refuge is on the side of a spiral tunnel or slope, that rotated around the ore body as it traversed lower, and in the higher regions of the mine, this was closed by a rock collapse. It appears to have been the only access to the deeper parts of the mine. In many countries there has to be a second way out, brought about after the Hartley Mining Disaster in the UK in 1862, when 199 miners died because the only shaft into the mine was blocked. (The first school I went to was at New Hartley, when my Dad was manager there).

Once the shaft has been sunk, then a small cage will be lowered to bring the miners to the surface, one at a time. The cage is obviously of small diameter:

The rescue cage at Quecreek.

Small as it is it held each of the miners and brought them to safety.

Rescued miner being brought out of the Quecreek Mine.

Let us hope that the miners in Chile are similarly all safely recovered.

Meanwhile, looking at other natural hazards, there have been about half-a-dozen 3.0 or greater earthquakes in the Loki area of Iceland in the last few days, and just when it appears that we will dodge the Hurricane bullet of Danielle, the next one seems to be forming behind it.

Deepwater Oil Spill - TV cameras and Chilean Miners

The fishing expedition to recover the drill pipe (DP) from the Blowout Preventer (BOP) at the top of the Deepwater well is moving somewhat slower than initially was suggested would occur. BP have provided a feed from the camera that was lowered into the stack.

It is not clear, since I wasn’t following this all day, what has been going on, though it has been suggested (H/t Unconformity) that the obstruction that appears in the video was one of the rams in the stack that was in the wrong position. This was followed by an adjustment of the stack, but apparently the camera has been returned to the surface. It may have malfunctioned, since the screen went blank just after this shot.

Note the time id.

UPDATE: Thanks to Acornus and MoonofA in comments at TOD, the object in front of the camera is apparently one of the two shear blades from the Ram in the stack which has failed to open. MoonofA has posted a better shot of the situation at about 6 am CDT. I have dotted in the rim of the hole further down, so that you can see that the extent that the rams still protrude, though they are higher up so the protrusion is greater.

The two blades blocking the hole

In the meanwhile it appears that it is being fed into the stack without a riser in place, though we could be getting the various BOP/stacks mixed up, since once the BP is out of the way, the intent is to move the DP11 BOP over the well, to replace the old one.

View from Enterprise ROV1

It looked as though, also just before the loss in signal, that the ROV1 grabbed hold of the DP to help steer it down the center of the stack assembly:

Enterprise ROV1 grabs pipe

ROV1 guiding pipe in stack

The pipe is now (11:40 pm) back out of the stack.

For those who have just heard about the 33 trapped Chilean miners, apparently they were working in the 2,250 ft level of the mine when, seventeen days ago, there was a massive roof collapse in the area that included the access shaft. After two weeks of exploratory drilling, a drill broke through in the area of the refuge where all the miners have been trapped. They are all still alive, one sent out a message to his wife attached to the drill, but it is impossible to reach them through the existing workings.

As a result a special rescue shaft will be drilled down, large enough to lower a cage into which, one at a time they can be extracted. (The technique was used to rescue the miners at Quecreek mine in the USA). The shaft will be 27-inches in diameter, but it is going to take up to four months to reach that level, and so the current shaft will be used to send down water, food and oxygen to sustain them until then. They have been able to run some equipment and generate electricity and have apparently some considerable room at the refuge site. It apparently takes a couple of days at a time to drill one of the smaller access holes.

Our prayers will remain with them and their families.

Deepwater Oil Spill - Flushing and Fishing

BP has now responded to Admiral Allen’s request for more information, and has obtained permission to replace the BOP and stack on the top of the Deepwater well, before completing the drilling of the relief well. They are also preparing to recover (fish for) the drill pipe that was left in the original well.

The permission letter from the Admiral reads, in the relevant section:


As a result, BP have flushed the subsea equipment which included the following steps:

The work began Wednesday afternoon and the flushing procedure will involve the following steps:
• The Discoverer Enterprise will attach a drill string to the top of the existing sealing cap.
• The middle blind shears of the sealing cap will be opened.
• The Q-4000 will pump an ‘anti-freeze’ mixture down through the existing manifold and into the BOP’s choke and kill lines. The liquid used in the flushing will be completely contained and carried to the surface through the Enterprise drill string.
• Following the flushing, the sealing cap’s blind shear ram will be closed.
Following successful flushing of the subsea equipment, BP will conduct an ambient pressure test to reassure that the well is secure. The test will be conducted over a 48-hour period, which mimics twice the time estimated to remove the original BOP and replace it with the Transocean Development Driller II (DDII) BOP.

At the present time it appears that the well is in the 48-hour period where the well is being held at the same pressure as that of the surrounding seawater, to see if there is any gain or loss in fluid or pressure under that condition. If there is no change, then the hardware will be removed, and the replacement BOP installed. It should be evident that there will be some care needed to deal with the 3,000 ft of drill pipe that may be still attached to the lower end of the initial BOP.

This was addressed in his press conference on Thursday by Admiral Allen, who introduced a new step in the process. After the current pressure test is completed, BP have now been tasked with seeing if they can recover the drill string from the well, before the BOP is changed out.

Bear in mind that the actual condition of the drill string is in some question. As the Admiral noted:

If you will remember when we cut through the riser pipe before we moved the stub of the pipe and unbolted the flange, we were concerned there might be pipe or even two pieces of pipe there.


 
And one of our procedures we were prepared to do was actually put a metal band around both pieces of the pipe, pull them together so that the spooling tool could fit over the top (inaudible) that connection between the blow out preventer and the capping stack.



When we actually cut the pipe and got in, we found out there was only a single pipe there. That leads us to believe that the pipe is suspended by the shears that closed but did not cut the pipe and the deep water horizon blow out preventer. 
 
And so we're working under the assumption that there is pipe suspended, held in place by the blow out preventer. We don’t know how far down it goes and we don’t know whether or not it is connected to the 5,000 feet of cement that was put in during the top kill.

So after the ambient pressure test is done, it would inform us as to whether or not the BOP could be removed without hydrocarbons being emitted. 
 
The next thing will be to see if we can remove that pipe. That doesn't preclude us from removing the blow out preventer and putting another one on. It will just make it a little more complicated and BP will have to provide us a procedure on how they will do that.

This fishing expedition (which was also addressed in Kent Wells discussion, though that has not been released yet) is expected to occur immediately after the pressure test, i.e. sometime on Saturday.

The fishing recovery (so-called because you have to “fish around” to find the bit and engage it) will involve attaching a specifically designed fishing tool to the end of a length of drill pipe and seeing if this can get sufficient hold of the drill pipe so that it can be recovered, if the shear ram holding it in place is released. The Admiral suggested that this would be a drill bit

We are going to actually put a drill bit down in the blow out preventer and attempt to extract the drill pipe. The reason we want to try and extract the drill pipe that reduces the risk that when we remove the blow out preventer and put the new one on, there won't be an (off score) or some kind of a bar to having a seal with the new blow out preventer.

I anticipate that the tool used will be quite different from the conventional bit – some options that I found to illustrate the range:

Fishing tools (Logan Oil Tools )

Bear in mind that the tool has to grip the drill pipe and hold the weight of the string under the BOP after the shear is released. The tool will have to penetrate into the deformed metal of the pipe (remember the picture of the pipe and riser other side of the shear) and get a good enough grip that it will hold up to 3,000 ft of DP. So the grip has to be a strong one. It will be interesting to see what sort of tool BP suggests using.

Screen capture of the sheared section of the drill pipe and riser.


There are also ongoing tests to see if the contents of the annulus can be established, since it is still not clear whether this is oil (which would indicate that at one time there was communication through the bottom of the annulus with the reservoir, and thus a failure of the annular cement around the casing) or it could be mud (from the well contents before the initial cement was injected). That may not be known, with confidence, however, until after the BOP is exchanged, and the relief well intersects the bottom of the borehole, which is now not expected to occur until after Labor Day.