Draw-Works

Draw-works is the primary hoisting machinery that is a component of a rotary drilling rig. Its main function is to provide a means of raising and lowering the traveling block. The wire-rope drilling line winds on the draw-works drum and extends to the crown block and traveling blocks, allowing the drill string to be moved up and down as the drum turns. The segment of drilling line from the draw-works to the crown block is called the "fast line". The drilling line then enters the sheaves of the crown block and it makes several passes between the crown block and traveling block pulleys for mechanical advantage.

The line then exits the last sheave on the crown block and is fastened to a derrick leg on the other side of the rig floor. This section of drilling line is called the "dead line". A modern draw-works consists of five main parts: the drum, the motor(s), the reduction gear, the brake, and the auxiliary brake. The motors can be AC or DC-motors, or the draw-works may be connected directly to diesel engines using metal chain-like belts. The number of gears could be one, two or three speed combinations
Draw-works is the core part of Drilling Rig. It is used for operation of lifting or laying down mast, hoisting or descending drilling tools and casings.

Technical performances and structure features

All bearings are rolling bearings. The shafts are made of alloy steel.
The chains are pressure lubricated.
The drum is grooved. The low-speed & high-speed ends of the drum shaft are equipped with ventilating pneumatic tube clutch. The brake rim (or disc) is water cooled and the surface is medium-frequency induction hardened that provides excellent wear-resistance capacity and long service life.
The contours of the sprocket teeth are medium frequency induction hardened. All transmission clutches are of involute spline type.
The main brake is hydraulic disc brake, and the auxiliary brake is electromagnetic eddy current brake or EATON brake.

Draw-works

The machine on the rig consisting of a large-diameter steel spool, brakes, a power source and assorted auxiliary devices. The primary function of the draw-works is to reel out and reel in the drilling line, a large diameter wire rope, in a controlled fashion. The drilling line is reeled over the crown block and traveling block to gain mechanical advantage in a "block and tackle" or "pulley" fashion. This reeling out and in of the drilling line causes the traveling block, and whatever may be hanging underneath it, to be lowered into or raised out of the wellbore. The reeling out of the drilling line is powered by gravity and reeling in by an electric motor or diesel engine.