I feel guilty relishing the engineering ingenuity of the Deepwater top kill attempt. I’m reminded of the fascination I had with the physics details of the 9/11 NY World Trade Center collapse, as they came out weeks and months after the horrible events of that day. In each case, my interest is in part (but only in part) distinct from the tragic nature of the events. The tragedies brought the amazing engineering and physics to my attention. I am a recovering physics/engineering geek and am permitted a relapse now and then. I … just … can’t … resist … my … curiosity.
But there is something therapeutic about learning the details. I’m upset. I’m powerless. I need to focus on something related that feels comprehensible, something connected to a solution of the problem or to questions about it.
With that as motivation, I herewith provide a beautiful excerpt from a wonderful post on The Oil Drum about top kill specifics:
The pumps will deliver the mud into the lines at a pressure of 6,800 psi, but as Kinuachdrach has correctly noted, it will then acquire the pressure from the full 5,000 ft column of mud as it flows down to the BOP, and enters the flow channel carrying the oil. Now we know that the BOP [blow-out preventer] rams are at least partially closed. If they are planning on using golf balls for the “junk shot”, it is feasible to surmise that the maximum width of the flow channel is no more than a third of a golf ball diameter. Not arguing the merits of American vs British ball sizes, let us assume that this is roughly half-an-inch (though it may have a greater length).
However, as flow volumes go up it requires more and more pressure for the fluid to get through a small gap. And at a given delivery pressure, only a certain flow volume will thus be able to escape that way. As long as this pressure exceeds that in the well, the net result will then be that the mud begins to push the oil and gas back down the well, and the well fills up with mud. The weight of that mud should then be enough to exert a pressure on the bottom of the well that is enough to exceed the fluid pressure in the rock and therefore stabilize the well and stop the flow of fluid out. Cement can then be pumped into the well to seal the top end. (Or with the flow stopped, another BOP can be put on the well to seal it). The main worry is that the hole in the top of the BOP is small enough to contain the additional flow volumes, and not allow the entire flow to escape upwards rather than being forced down the well. The higher flows might, in addition, if they do exit the riser, further erode the openings. This could increase the oil flow, as it lowers the resistance.
There’s so much more, with diagrams and videos.
