There are eight wire lines that connect it with the Travelling block and the drilling hook below it. The drum is located in the draw-works and is operated with a drum brake. The dead line anchor is connected to the storage reel. The swivel is connected to the rotary drilling hose, which is used to pump drilling fluid into the drill string. Below the ocean surface, various components are of importance, including the gamma ray, directional survey, pressure, temperature, and the weight on the bit. Communication regarding these components occurs via mud pulsing and other methods. Drill collars are used to exercise weight on the bit for penetration into the ocean bed. The weight of the drill string contributes to this. The downhole motor is especially helpful when directional drilling is involved.

In deep ocean situations Grant Prideco's extreme Torque Drillpipe allows high tongue for Extended Reach Drilling (ERD) wells. The Kelly pipe functions as a connecting device between the rotary table and the drill...

The casing spool holds the upper end of the casing strings, while the pipe ram seals around the pipe. In a flowing well, the shear ram can cut the pipe as a last resort to avert spills. The annular BOP is a rubber donut that seals around the pipe or open hole. The bell nipple adds drilling fluid into the drillstring. This includes a return line. The mud motors are in operation while the drillstring does not rotate.
The drilling fluid has some very specific functions in ERD. It minimizes the loss of fluid to the formation, controls formation pressure, lubricates the drill string, maintains borehole stability, suspends barite under static and dynamic conditions, removes drilling cuttings from the hole, and provides hydraulic horse power to the bit. These are all highly important functions to maintain successful drilling in deep water conditions.

Special offshore systems include the riser system and its components, motion compensation systems, subsea equipment, and booster pumping systems.