In drilling wells for gas. oil. or water the most common outfit employed is the familiar der rick rig of the oil regions, combined with a boiler, engine, drill. and accessories, and the necessary hoisting apparatus for raising and lowering the drills and the sand pumps. In the case of oil wells the derrick and power plant may be left in place to operate a pump, the lat ter being substituted for the drill. Derricks for drilling wells are some 20 feet square at the base, 70 feet to 100 feet high:built up of either timber or steel. The engine drives a hand wheel to which a pitman i76 attached. The pitman works a walking beam, supported by a Samson post. To the other end of the beam the string of tools is attached. The tools include a drill, above which there is an auger stem, jars, a sinker bar, and either cable or wooden poles for suspending the string of tools as the hole is deepened. The drill and accessories are lifted by the walking beam. The is a device acting on the principle of two loose links of a chain and designed to loosen the drill by giving a jar ring, upward blow. A temper screw is pro vided for minor adjustment of the drill as to depth. As the work progresses it is necessary to lift out the drill and accessories and substi tute a new one, at the same time using the sand pump to remove the ma terial loosened by the drill. A bull wheel at the base of the derrick and a crown pulley at its top. together with a cable, are used to lift the tools, by means of the engine. A sand reel at the base of the derrick, a sand pump pulley at its top, and a sand pump line perform a like ser vice for the 1)111111). Be sides the tools named there arc special tools for use in sinking the well, and an almost end less variety of fishing tools for recovering lost or broken drilling tools. The casing generally follows pretty closely after the drilling. Packing rings of corrugated rubber and other devices are used to shut out any for eign fluid from the easing. Deep wells are often begun with large casings. When such a easing has been sunk as far as practicable a smaller one is inserted within it.
The cost of a full-sized artesian well outfit, such as is commonly used in the oil wells and for deep artesian wells, is about $10.000. Slnch simpler and cheaper rigs are used for smaller wells, horse power being substituted for steam. Very effective work is often done by a spring pole operated by two or more men. The tools are suspended from the free end of it pole or beam, which is rigidly secured at or near the other end. The men pull down the pole, then slack the
ropes, whereupon the pole flies back into a hori zontal position. lifting the drill with it.
Well-sinking of one sort or another is older than history. Comparatively large wells nat urally preceded the- bored and drilled ones by many centuries. Some of these, even in early times, were a hundred or more feet deep. A laborious method of drilling was employed cen turies ago by the Chinese and 'Hindus. The drill was raised a few feet at a time by means of a rope attached to a lever, then it was let fall by its own weight. deep well-sinldng meth ods had a rude beginning early in the nineteenth century. In ISIS an impulse to the movement for better methods was given by the French So ciety for the Encouragement of Agriculture. The Grenelle and Passy wells for the supply of l':r•is were ten and six years in the sinking. The (:renelle well is 1750 feet deep. S inches in di-unter, and was completed in 1842. The Passy well is 1913 feet in depth. yields 5.500,000 gallons a 'lay, and was completed in 1861. The well was started with a diameter of 40 inches. The wrought iron drills were lifted by means of pole, ei,!hf inches square. .tars similar in principle to those already described were used. Subsequent ly a well 17 inches in diameter and 2900 feet deep was drilled at Butte-aux Cailles, the drill being worked by a walking beam and steam engine. The first well sunk ex clusively for oil was put down near Titusville, Pa., in 1S59, by Colonel E. L. Drake. It was sunk by a small derrick rig. Since then the American system of well-drilling, as already described, has been adopted for putting down water, oil, and gas wells all over the world. It is notable for the comparative simplicity and effectiveness of the machinery employed and for the ingenuity displayed in overcoming all difficulties. In 1572 what was at least one of the earliest nat ural gas wells was sunk at Newton. Pa. The gas from it was piped through a two-inch main and a :;1/4-inch pipe line, miles long. to Titus ville, Pa.
Among the deepest wells that hove been put (Iowa the accompanying table shows the most important: BIBLIOGRAPHY. Cox, Artesian iVells I Brisbane, Bibliography. Cox, Artesian iVells I Brisbane, Queensland, 18951, a semi-popular account at the methods and machinery employed in their con struction; Wehster, "Natural Gas in the United States," in Cassirr's Magazine (New York. Feb ruary. 1895). See ARTESIAN WELLS; GAS.
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