National Geographic : 1972 Jun
is done by pumping a cement slurry, or mix ture, down the inside of the casing. It is forced out through the bottom, and rises to fill the space between the outside of the cas ing and the walls of the drill hole. After the first "string" of casing is set, "blowout preventers" are installed on the well. These highly important safety devices can close off the space between the drill pipe and the casing in a matter of seconds if un expectedly high pressures are met, and con tain these pressures until normal drilling can be resumed. When the well is ready for pro duction, a system of high-pressure surface valves, called a Christmas tree, is installed on top to control the well flow. Or, if the well does not flow naturally, a pump can be added. On the platform, the oil and gas are separated and sent to shore through pipelines. Onshore and offshore, between thirty and forty thousand oil and gas wells are drilled around the world every year. Yet, only a handful result in those violent erup tions called "blowouts"-but the possibility is still there. A prevention paradox. Prevention is the most effective way to deal with the problem of blowouts. To that end, Jersey has established training facilities in the U.S. and abroad for drilling superin tendents and contract crews from our affili ates all over the world. Our main school is centered around a mile-deep well on the King Ranch in Texas. This practice well is the real thing. It has storage tanks, a pump, control manifold, a full array of pressure gauges and controls all the diverse equipment that is used in the field to prevent a blowout. Oddly, all this training represents some thing of a paradox, set up mainly because there are so few blowouts. Since drillers may never experience a runaway well, the schools give them an opportunity to improve their skills in control and prevention. Four times deeper. As the demand for energy grows stead ily, the search for new sources of oil and gas has moved ever farther offshore and into deeper waters. This has necessitated refine ment and extension of the methods used for In deeper water, we'll need platforms as tall as skyscrapers. many years in shallower waters. Recently, Humble has devised a system that will make possible the development and production of oil and gas in waters ranging from 700 to 1500 feet deep. This is from two to four times as deep as any offshore fields now producing. A basic component in the Humble deep water system will be, of course, drilling plat forms. The first one will be a real giant. Plans call for a huge four-legged structure in nearly 800 feet of water, and weighing more than 20,000 tons. As many as sixty wells can This is a sixteen-foot model of what someday may be the tallest offshore platform. It will be nearly as tall as the Empire State Building, but only the tip will rise above water. be drilled directionally from its 150-foot square deck. Each of the giant's four legs will be seventeen feet in diameter, and they will straddle more than an acre of the ocean floor. The SPS. The second part of the project-for the deepest waters-will be Submerged Produc tion Systems, secured to the bottom of the sea. Each SPS will include a cluster of wells drilled directionally from floating rigs. The whole underwater operation in volves advanced technology, with electronics to monitor and "instruct" each unit, hydraul ics to open and close valves, and safety de vices that will automatically close off any part of the system that malfunctions. Oil and gas from each SPS will flow through pipelines to points on centrally lo cated platforms, and from there to shore.