Oil casing drilling is also called percussion drilling. The steel wire rope is used to send the drill bit to the bottom of the well, and the beam mechanism is driven by the driving force to make one end of the beam move up and down, and the steel wire rope and the drill bit are impacted up and down, so that the rock is broken. The drilling speed of the Dayton drill is generally relatively slow, and the efficiency is very low, which can not adapt to the increasing depth of the well and the complicated formation drilling requirements, so it has been gradually replaced by rotary drilling. However, its equipment is relatively simple, its cost is low, and it will not pollute the oil layer. It can be used in some shallow low-pressure oil and gas wells and lost wells. Downhole power drilling is the use of downhole power drilling tools to drive the drill bit to break the rock. The drill string does not rotate during drilling, its wear is relatively small, and the service life is long. It is particularly suitable for drilling directional wells. Downhole power drills are divided into turbo drills, electric drills and screw drills.
Casing pipe is used for oil well drilling. It is mainly used to support the well wall during drilling and after completion, to ensure the progress of the drilling process and the normal operation of the oil well after completion. Petroleum casing can be divided into two types: short-thread casing and long-thread casing. According to national regulations, domestic casings should be bundled with steel wire or steel tape, and the exposed part of each casing and coupling thread should be screwed with a protective ring to protect the threads.
The cutting or grinding action generated when the drill bit rotates causes the rock to be crushed. Rotary drills are currently more common drilling methods. The drilling speed is much faster than that of the Dayton drill. It is easier to deal with the complex conditions of well collapse and blowout. According to the power transmission method, the rotary drill can be divided into two types: downhole power drill and rotary table drill. The turntable drill is equipped with a turntable at the wellhead of the drill floor. There is a square hole in the center of the turntable. The square drill rod at the upper end of the drill string passes through a square hole. The bottom of the square drill rod is connected to the drill string and drill bit. Rotate with the drill bit to break the rock.
In general, oil casing is an indispensable equipment for oil drilling. Its main equipment also includes drill collars, core pipes, drill pipes and small-diameter drilling steel pipes. At present, domestic oil casings are made by hot rolling or cold drawing.
