Cat shaft and coring reel group ( drilling rig ) – Readyzone

draw - works

Fig. 1 – The Draw Works

Cat shaft and coring reel group

The cat shaft and coring reel group comprises the cat heads, the cat shaft assembly and the coring reel drum( Figure 1 ).

The cat heads are spool-shaped, rotating drums powered by the jack shaft assembly. They consist of friction and mechanical rotating heads.

The friction cat heads are used to transport heavy objects around the rig floor by means of a manila rope.

The mechanical cat heads comprise the make-up cat head on the driller’s side and the break-out cat head on the opposite side. The mechanical cat heads are spooled with a suitable length of wire line which is connected to tongs. The line coming out of the mechanical cat heads on the driller’s side is termed the make-up line and the corresponding tong is described as the make-up tong. The make-up tong is used to tighten the drill pipe joints when the drill string is being run into the hole.

The mechanical cat head on the opposite side of the driller is described as the break-out cat head; the line and tong are also described as break-out line and break-out tong, respectively. The break-out tong is used to break the drill pipe joints the removal of pipe from the hole.  

Coring reel drum

The coring reel drum contains sufficient small diameter( usually 9/16 in ) wire line to reach the bottom of the hole. It is used for lowering and retrieving any device to the hole bottom. Deviation records are one example. At any time, a deviation record can be lowered down the centre of the drill string to come to rest sitting above the drilling bit. After a preset time delay, a clock work mechanism is activated to punch a pinhole in a paper disc, and then the deviation recorder is lifted out on the coring reel. The position of the pin hole shows the deviation of the hole from the vertical.

Related Links:-

*  Derrick              *  Drill collar             *  Kelly Drive

*  Drill pipe          *  Rotary table         *  Swivel

*  Tool joint          *  Draw works

Drum shaft group                               *  Hoisting drum

*  Auxiliary brake                                     *  Brakes

Cat shaft

Reference : H. Rabia, Oil Well Drilling engineering-Principles and Practice

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