In a

drilling rig A drilling rig is an integrated system that drills wells, such as oil or water wells, or holes for piling and other construction purposes, into the earth's subsurface. Drilling rigs can be massive structures housing equipment used to drill wat ...

, the drill line is a multi-thread, twisted ''wire'' rope that is threaded o
reeved
through in typically 6 to 12 parts between the

traveling block A traveling block is the freely moving section of a block and tackle that contains a set of pulleys or sheaves through which the drill line (wire rope) is threaded oreevedand is opposite (and under) the crown block (the stationary section). The ...

and

crown block A crown block is the stationary section of a block and tackle that contains a set of pulleys or sheaves through which the drill line (wire rope) is threaded oreevedand is opposite and above the traveling block. The combination of the traveling b ...

to facilitate the lowering and lifting of the

drill string A drill string on a drilling rig is a column, or string, of drill pipe that transmits drilling fluid (via the mud pumps) and torque (via the kelly drive or top drive) to the Well drilling#Drill bits in mechanical drilling, drill bit. The term ...

into and out of the

wellbore A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petrole ...

. On larger diameter lines, traveling block loads of over a ''million'' pounds are possible. To make a connection is to add another segment of

drill pipe Drill pipe, is hollow, thin-walled, steel or aluminium alloy piping that is used on drilling rigs. It is hollow to allow drilling fluid to be pumped down the hole through the bit and back up the annulus. It comes in a variety of sizes, strengths, ...

onto the top the

. A segment is added by pulling the

kelly Kelly may refer to: Art and entertainment * Kelly (Kelly Price album) * Kelly (Andrea Faustini album) * ''Kelly'' (musical), a 1965 musical by Mark Charlap * "Kelly" (song), a 2018 single by Kelly Rowland * ''Kelly'' (film), a 1981 Canadi ...

above the rotary table, stopping the mud pump, hanging off the drill string in the rotary table, unscrewing the kelly from the drill pipe below, swinging the kelly over to permit connecting it to the top of the new segment (which had been placed in the

mousehole Mousehole (; kw, Porthenys) is a village and fishing port in Cornwall, England, UK. It is approximately south of Penzance on the shore of Mount's Bay. The village is in the civil parish of Penzance. An islet called St Clement's Isle lies ab ...

), and then screwing this assembly into the top of the existing drill string. Mud circulation is resumed, and the drill string is lowered into the hole until the bit takes weight at the bottom of the hole. Drilling then resumes.

External links

Drill line
{{Petroleum-stub Oilfield terminology Drilling technology