Drill String

Drill string is the combination of the drillpipe, the bottomhole assembly and any other tools used to make the drill bit turn at the bottom of the wellbore. The drill string is hollow so that drilling fluid can be pumped downhole through it and circulated back up the annulus.

Drill Pipe :

Drill pipe is a portion of the overall drill string which connects the rig surface equipment with the bottom hole assembly and the bit both to pump drilling fluid to the bit and to be able to raise, lower and rotate the bottom hole assembly and the bit. It a thick walled, hollow, steel piping used for both conventional as well as horizontal drilling. Drill pipes are available in a variety of sizes, strengths and weight. We provide to our clients the size and strength they prefer.

Drill Collar :

Drill collar is a component of a drill string that provides weight on bit for drilling. These are thick-walled tubular pieces machined from solid bars of steel, usually plain carbon steel but sometimes of nonmagnetic nickel-copper alloy or other nonmagnetic premium alloys. The bars of steel are drilled from end to end to provide a passage to pumping drilling fluids through the collars. The outside diameter of the steel bars may be machined slightly to ensure roundness, and in some cases may be machined with helical grooves.


HWDP is a type of drill pipe with thick walls and collars are longer than conventional drill pipe. HWDP tends to be stronger and has higher tensile strength than conventional drillpipe. It provides a flexible transition between drill collar and drill pipe along with additional weight to drill bit.

Kelly :

The kelly is a square, hexagonal or octagonal shaped tubing that is inserted through and is an integral part of the rotary table that moves freely vertically while the rotary table turns it.The upper end of the kelly is screwed into the swivel, using a left-hand thread to preclude loosening from the right-hand torque applied below. The kelly typically is about 10 ft longer than the drill pipe segments, thus leaving a portion of newly drilled hole open below the bit after a new length of pipe has been added and the drill string has been lowered until the kelly bushing engages again in the rotary table.

Drill Pipe

Drill Collar