A fine-grained sedimentary rock composed mostly of consolidated clay or mud. Shale is the most frequently occurring sedimentary rock.

A vibrating screen used to remove cuttings from the circulating fluid in rotary drilling operations. The size of the openings in the screen should be carefully […]

Shallow hazards are adverse drilling subsurface conditions that may be encountered prior to the setting of the first pressure containment string and the emplacement of the […]

A relatively small container of high explosive that is loaded into a perforating gun. On detonation, the charge releases a small, high-velocity stream of particles (a […]

The component in a blowout preventer that cuts, or shears, through drill pipe and forms a seal against well pressure. Shear rams are used in floating […]

1) a grooved pulley. 2) support wheel over which tape, wire, or cable rides.

Established at the bottom end of the conductor casing by cementing. See leak off test and conductor casing.

The appearance of oil or gas in cuttings, samples, or cores from a drilling well.

The pressure at the bottom of a well when the surface valves on the well are completely closed. It is caused by formation fluids at the […]

The difference between the formation pressure at the bottom of the well and the hydrostatic pressure in the drillpipe. Recorded when a well is shut in […]