Four-vehicle Units
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for Oil Discovery FOUR different vehicles form a reflection unit of the type whicb Hands-England Oilfields Equipment, Ltd., Letchworth, is producing for Seismograph Service, Ltd.
Such a unit is used purely for exploratory purposes, the drilling rig in this instance being capable of making a shot hole about 600 ft. deep. (It may be necessary to drill to 20,000 ft. or more for oil.) A unit of minimum size comprises a drilling rig, a vehicle for carrying water, a shooting truck, and a vehicle containing the recording apparatus.
The Hands-England drilling rig, based generally on existing types, has a fabricated tubular steel mast which stands 19 ft. 9 .ins, above the rotary table The power for all operations is supplied by the engine of the vehicle. Distribution to the various units is through an enclosed chain driven transfer box incorporating clutches running in oil.
The Drives and Controls
From the transfer box, drives are taken to a high-capacity water pump, a four-speed-and-reverse gearbox which drives the rotary table, the pull-down gear with hydraulically controlled loading, and to double-drum winch gear equipped with friction clutches and bald brakes.
All controls are grouped on the lefthand side, at the rear, and comprise levers connected to the brakes and clutches of the winch gear, to the rotary table, pull-down gear, pump, power-take-Off, and engine clutch. A throttle lever and a hydraulic control valve for the pull-down gear are also conveniently located.
One of the most important components on such a drilling rig is the water pump, which has to maintain a continuous supply of water through the tubular drill shaft. As the water forces its way from the drill head it brings with it the earth and other deposits loosened by the drill. As it is a circulatory system, the pump must be capable of dealing with water that is far from clean.
The second vehicle of the unit is the water truck. those being produced by Hands-England. Ltd., being designed to carry 420 gallons. An interesting feature of these vehicles is that water is raised to the tank by means of engine suction.
On exploration work, the drilling rig makes a hole to take an explosive charge. When this charge is detonated, vibrations are set up in the surrounding area. These are picked up on sensitive electrical apparatus, amplified, and recorded photographically. From the records thus obtained, geologists are able to determine the nature of the earth's structure from which, in turn, they can make reasonable predictions as to the possibility of the area being an oil-bearing one or not. The explosives are carried on shooting truck, which also accommodates 420 gallons of water. The lockers for carrying the powder are built into the sides of the water tank. Provision is made to carry 40 poles, which are used for loading t h e hole with explosive. Winch gear and an A frame at the rear are other items on the shooting truck.
The fourth vehicle—the recording truck—has an electrically welded steel body in which is carried the electric amplifiers and recording camera'. The area of the instrument panel is almost equal to the width and depth of the body. Batteries for operating the recording in3truments are carried in a forward compartment, and built on to the back of the body are two powerdriven winches each having its own motor. No fewer than 500 items of equipment go with each recording truck.
An outstanding feature of all four vehicles is their obvious solidity of construction. The vehicles inspected bad reconditioned Chevrolet 4 by 4 chassis.