| Published: May 28, 2010 – 9:56 am
For over a month now, a broken oil well has been gushing into the Gulf of Mexico.
The last few days, Iâ€™ve appeared on CNN, MSNBC, and Fox News regarding the oil and gas gushing from the Gulf of Mexicoâ€™s seafloor. Watching and listening to spokesmen and reporters up close gives one a deep sense of how serious this whole business is. From the chairs in these various studios, itâ€™s quite a ride.
When we drill into a deposit of oil, it often comes gushing out because the hollow spaces underground hold natural gas along with liquid oil. The gas acts like the propellant in a can of hairspray or paint. It was produced by ancient bacteria, and its pressure is still there. When we poke a hole in the underground cavity, sometimes we get a gusher; sometimes we get what petroleum workers often call, a â€śblowout.â€ť The Deepwater Horizon rig was destroyed by a catastrophic blowout of natural gas and oil. It caught a spark, probably from one of the dozens, or hundreds, of electric motors on board, and the whole rig blew up killing 11 men.
With all this, oil workers look to avoid blowouts. Whenever we run pipes anywhere, we put valves in the lines. For a couple of centuries, we have been drilling for oil. So at the top of each well, we put a shutoff valve. Â The bigger the well; the bigger the shutoff. This well is huge, 53 centimeters (21 inches) across. So, the shutoff valve is huge. It weighs more than a hundred tons. By long tradition, itâ€™s called a Blow-Out Preventer (B.O.P.).
Here, the expression â€śpreventerâ€ť is, at best, inappropriate. It didnâ€™t prevent anything as far as we can tell.
The idea now is to pump a fluid that will block the flow. In the oil field this fluid is often a special mixture whose molecules lock together when itâ€™s under pressure. Oil drillers call it â€śmud.â€ť It looks like mud, but thereâ€™s more to it.
The molecular lock-together feature of a fluid is called â€śdilatancy.â€ť The classic dilatant fluid in our everyday experience is cornstarch mixed with a small amount of water. Itâ€™s goopy, until you slap it or shake it. It locks up and does not splatter at all. So it is with drilling mud.
British Petroleum (BP) has been pumping drilling mud into the Preventer plumbing for almost two days. It seems to have slowed the oil flow a little, but not enough.
The engineers, or at least the spokesmen for the engineers, said they plan a â€śjunk shot.â€ť The idea is to add bits of hardÂ material to the mud. Traditionally, in the Texas oil field, drillers add cut-up car tires and old driving range golf balls. This â€śbridgingâ€ť material sometimes helps the dilatant mud molecules lock up. The pipe is so big, and the flow so fast, that a golf ball isnâ€™t really that big an object. It could easily jam against an edge or pipe jointâ€“ and that would be good. Looking at the BP executiveâ€™s faces, it doesnâ€™t seem like this is going to work either.
Next, I expect engineers along with the Remotely Operated submarine Vehicle (ROV) drivers will cut some large portion of the top preventer off. The next pipe up the drill string is called the â€śriser,â€ť and I imagine thatâ€™s what theyâ€™ll go after next. Itâ€™s big job because the material is a hard type of stainless steel. And, itâ€™s a long way around the big pipe with a fancy saw and buffing grinder, especially when youâ€™re doing it with a claw-fingered robot to work the material and grainy video to guide you.
After that, I hope the managers let go of the idea of trying to capture any more oil until the relief, or drilled-in-from-the-side, well is cut. I hope they put a cap or slug made from a few thousand tons of concrete on top. They could let it ooze very slowly for a few weeks, until they can get to the well casing or liner by coming in from the side. Drilling these relief wells will take a few months, because itâ€™s, once again, miles down and hundreds of meters of solid rock.
About the rate of oil flow: there have been a great many questions about how much oil is flowing per day. At first, looking at satellite data, people thought it was about 5,000 barrels a day. A barrel is 42 gallons. So, itâ€™s a great many gallons. (A â€śdrumâ€ť is 55 gallonsâ€“ another confusing feature of the old English system of units.) Well, it turns out most of the oil isnâ€™t making it to the surface of the sea. Itâ€™s floating somewhere in between the sea floor and surfaceâ€“ a goopy mess for any living thing in the ocean.
I have some small experience in oil fields, or in the â€śoil patch.â€ť I worked for a shipyard that built the worldâ€™s premier oil slick skimming boat. We had a machine derived from skimming technology that performed the seemingly trivial task of separating oil and water.
You might think it would be easy, but in nature, dust particles or plankton organisms (plankters) get covered with oil in such a way that they neither sink nor float. Theyâ€™re neutrally buoyant. As small globs of oily goo, they clog up all kinds of plumbingâ€“ including the gills, fins, and wings of fish and birds.
This fundamental experience helped me explain to news anchors and viewers why there was such discrepancy between the National Oceanic and Atmospheric Administrations satellite assessment of size of the spill compared with the measurement of the pipe gusherâ€™s oil leak.
I hope BP takes this business very seriously. Any information they are not disclosing will come out one day when various employees or friends of employees reveal the true decision process. I remain concerned that the traditions of oil spills on land are too strongly influencing the procedures being developed on the bottom of the Gulf, an ecosystem people all over the world depend on.
We use a lot of energy. This disaster helps us recognize how complex or oil technology is, and how much can go wrong. Letâ€™s learn from this, wean ourselves from oil, and change the world.