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View Diary: Fracking in California must not be regulated. (113 comments)

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  •  We should at least understand the technology (5+ / 0-)
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    RLMiller, caul, Senor Unoball, 6412093, ColoTim

    and the risk involved in drilling for oil and gas. Obviously all the light sweet crude close to the surface is gone so going after what remains is more difficult, costs more money, has more risk of gushers becoming blowouts.

    We observed some of that with the gulf blowouts, the north sea blowouts, the arctic blowouts, the routine blowouts that have been occurring every year since the first wells were drilled.

    Oil is lighter than water and sits on top of it. gas is lighter than oil and sits on top of that. Technology now allows small pockets to be "washed out" with solvents under pressure in ways that breach the seals of the bentonite drilling mud and leave behind hazardous wastes that can drain down into aquifers.

    The deeper you go the greater the weight of the rock you are drilling through and the more pressure it places on the drill hole.

    When a well is drilled a casing along with a wash of drilling mud keeps soil and other particulate matter from sedimenting at the bottom of the drill hole trapping the drill bit. Some of the mud leaks out and seals the hole as it dries out

    The drilling mud that remains picks up all the spalls of rock from the percussion and abrasion of the drilling head and moves them up out of the hole under pressure to a sediment pond then the mud is recirculated with pumps under pressure.

    Like a submarine, the deeper the well goes the more pressure on the hull or casing. The drilling mud has to be under pressure equal to that of the rock to keep the drill hole from collapsing.

    Deeper wells that are thousands of feet below the surface have pressure problems that wells close to the surface don't have.

    The more load the weight of the rock adds (144lbs/cubic foot) the more pressure that has to be resisted. In practice its 1 pound per square inch per foot of depth so at 6000 feet the hoses pumping the drilling mud into the hole have to take 3 tons of pressure per square inch.

    When the drill bit reaches the layer with gas the pressure drops dramatically so unless the pressure of the drilling mud is dropped the well blows out. Its hard to judge exactly when this will occur because the drilling mud providing the feedback on how the hole is going has to travel 6000 feet to reach the surface. To prevent sudden surprises the mud is thickened, made denser so the drilling goes slower by a factor of as much as 100.

    Obviously a slower drill rate is costly. If the mud is too dense it can bind the bit, sediment up the hole and kill the well. Drillers tend to keep pushing to go as fast as possible until and even after the risk becomes prohibitive.

    Blowout preventers are a backup system that is supposed to keep the gas from exploding up the pipe pushing the 6000 feet of drill pipe ahead of it, taking out the derrick, and everybody on site. They can be used to slow the flow or kill the well.

    It used to be that the gas was flared off but now it is recovered, hopefully without any damage to the well and then the drilling for oil continues.

    With really dirty oil, high in carbon and sulfer, various other petrochemicals like butane and ethonol can act as solvents washing out the bentonite seals over time and again letting chemicals including those placed in the drilling mud to control its properties wash out into the aquifer below.

    Like fire, nuclear power, oil, gas and coal are a calculated risk we accept because A. we think we can control it. and B. cheap energy makes the high quality of life to which we have become accustomed possible.

    With seven or eight billion people on the planet a few hundred or thousand or even hundreds of thousands and millions of deaths may be thought of as collateral damage.

    Guns, automobile accidents, infectious diseases, climate change, opportunistic diseases, plague, pestilence, overpopulation, pollution, resource war all take their toll.

    We are to the point where we now take species extinctions as collateral damage and are getting to where some of those species extinctions will threaten our own survival.

    Its maybe time to say enough, to just say no, to do the equivalent of quitting smoking so we can keep breathing a while longer.

    Live Free or Die --- Investigate, Incarcerate

    by rktect on Fri Jul 12, 2013 at 06:40:33 AM PDT

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