An opening or space within a rock or mass of rocks, usually small and often filled with some fluid (water, oil, gas, or all three). Compare […]

1) the condition of being porous (such as a rock formation). 2) the ratio of the volume of empty space to the volume of solid rock […]

A choke in which the orifice size must be changed to change the rate of flow through the choke. See choke and orifice.

These are air or hydraulic elevators operated on bails hanging below the traveling equipment, which provide a remote opening and closing of the elevator without human […]

See Slips.

The utility functions associated with a traditional mousehole, such as hoisting, lowering, rotating, and grabbing or actuating with a slip assembly. Usually associated with facilitating offline […]

The initial nitrogen charge in the accumulator. The nitrogen gas charge is compressed by the pumps hydraulically charging the accumulators and is used to expel the […]

The force that a fluid (liquid or gas) exerts uniformly in all directions within a vessel, pipe, hole in the ground, and so forth, such as […]

An instrument that measures fluid pressure and usually registers the difference between atmospheric pressure and the pressure of the fluid by indicating the effect of such […]

A scale of pressure differences in which there is a uniform variation of pressure from point to point. For example, the pressure gradient of a column […]

A valve that opens at a preset pressure to relieve excessive pressures within a vessel or line. Also called a pop valve, relief valve, safety valve, […]