(also, “drilling margin”) The drillable pressure profile, bounded on the low side by formation pressure, below which formation fluids will enter the wellbore, and on the […]

A ship constructed to permit a well to be drilled from it at an offshore location. Although not as stable as semisubmersible MODUs, drillships are capable […]

Device used to transmit torque from the rotary table to the kelly but allow vertical movement of the kelly while drilling. It may have pins fitting […]

1) a cylinder around which wire rope is wound in the drawworks. The drawworks drum is that part of the hoist on which the drilling line […]

Somewhat loosely used in oil work, but in general any well that does not produce oil or gas in commercial quantities. A dry hole may flow […]

Utilization of two active heave drawworks to provide full load compensation without the need of a crown-mounted compensation system and to increase the speed of the […]

Dual gradient drilling (DGD) is a subset of MPD. As defined by the IADC, DGD means “two or more pressure gradients within selected well sections to […]

In a parallel racking system often the design will include a second racker on the same track system. This is to facilitate redundancy as well as […]

The portion of a stud or screw which remains in place after the head has been twisted off in an effort to remove the entire stud […]

Trade name for a downhole motor driven by drilling fluid that imparts rotary motion to a drilling bit connected to the tool, thus eliminating the need […]

A method by which a floating offshore drilling rig is maintained in position over an offshore well location without the use of mooring anchors. Generally, several […]