Page:The New International Encyclopædia 1st ed. v. 20.djvu/497

* WELL-SINKING. 421 WELL-SINKING. WELL-SINKING (AS. well, icel, well, spring, Olli:. inllii. (In. W ' lie, wave, liillow. from AS. u-eallan, (IIIU. iidlhni, Ger. icalleii, to well, boil U[) ; eoniK'cteil with Lilh. riln'm, OCliurch Slav. vlihifi, wave, billow, I.at. volvere, Gk. liM'nv, cili/rin. to turn. SUt. ilrnii, wave). The digging, boring, or drilling of holes in the earth for the development of supplies of water, petroleum, natural gas. or salt. The jjroeess is generally aceompanied or immediately followed by the curbing or easing of the well to prevent it being ehoUeil by the material penetrated, or to shut out all liquids except the yield of the stratum which the well is designed to tap. Besides the development of subterranean liipiids, wells or their ecjuivaleiit in construction arc also used in jirospecting for solid minerals and in determin- ing the character of soil and rock, fovuidations, .'uul other engineering structures. Wells vary in diameter from I inch to 100 feet and in dcjjth from 5 feet to 6000 feet. The methods of sink- ing employed depend upon the character and depth of the material penetrated, rather than the object for which they are sunk. Wells are classified according to the methods of sinking, as dug, drilled, bored, driven, and jet ; bj' the lining employed, as curb tube, and ease; as open, in the ease of relatively large, shallow Wells; as shallow or deep; and as artesian, flow- ing, non-dowing, or iiiun])ing. as the case may be. Wells from a few feet to a hundred or so in diameter and depth are generally sunk by means of ])icks and shovels, or bj' digging. The sides frequently require to be supported while the sinking is luider way, particularl.y if quicksand or large quantities of water are encountered. Sheet-piling or planks driven into the ground at the outer edge of the excavation may be em- ployed, with proper cross-bracing where neces- sary, or a wooden or metal crib or caisson pro- vided with a shoe or cutting edge may be used. The latter generally sinks of its own weight if the material within the well is removed, The sinking process may be and generally is aided by building the curb or lining wall direetl}' on the shoe, the increasing weight gradually forcing the shoe and curb downAard. INIore or less water is likely to be encountered. It may be re- moved by a centrifugal pump, a pulsometer, or a direct-acting steam pump. .Small wells of no great depth, jirovided with a metal tubing or casing, are often driven by luimmer blows, whence the name driven or tubular wells. The tubes thus driven may have solid, pointed ends or drive points, or their lower ends may be open. In any case the lower sections must be perfo- rated. Both round holes and slotted holes are eni]iloyed. and where very fine material is en- countered gauze wire strainers may be necessary. If the well-casing is open at the bottom the ma- terial pierced must be removed by sand pumps or buckets, or by a hydraulic or steam jet. Arte- sian wells and most other deep wells jienetrate more or less rock. Some shallow wells also go through or into rock, particularly in i)ros]iecting for coal and the like, or in exploring for foiuida- tions. In all such eases resort is had to drill- ing. For relatively small and shallow holes ordi- nary hand drills and diamond drills may be used. (See Drill.) _But in most operations for water, gas, and oil wells, a regular drilling rig is necessary after rock is struck. So long as the sinking is through sand or other easily worked material, wroughtiron or steel tubing may be driven down with mauls, <'ither by liancl, horse, or steam power; by means of a jet; or by the sand pump or liucket method, combined with rotation of the tube or casing. The hydraulic jet is simply a stream of water under pressure introauced at the bottom of the well through a supply pipe, or through a hollow drill. The force of the water aids in loosening the material and also brings it to the surface. The sand pump or bucket is a simple form of pump, low- ered into the well hole, filled, raised, and emptied. In drilling wells for gas, oil. or water the most common outfit employed is the familiar der- rii'k rig of the oil regions, eondiined with a boiler, engine, drill, and accessories, and the necessary hoisting ap])nratus for raising and lowering the drills and the sand pumps. In the case of oil wells the derrick and power plant Sand Pump Pulley- Sand Pump tine- OUTFIT FOR DRILLING DEEP WELLS. (The band wheel-is driven by an engine.) 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 band wheel to which a pitman is attached. The ]iitman 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 jar is a device acting