W.T.I.

The West Texas Intermediate grade has become the "marker" crude in North America and is the contract grade for the important NYMEX crude oil futures contract. Quoted on the basis free in pipeline at Cushing, Oklahoma.

Waiting on cement

Pertaining to, or during the time, when drilling or completion operations are suspended so the cement in a well can harden sufficiently.

Wall cake

See filter cake and mud cake.

Wall sticking (of drill pipe)

A condition downhole when a section of the drill string becomes stuck or hung-up in the deposit of filter cake on the wall of the bore hole due to excess differential pressure.

Wash-over pipe

A pipe run at the end of drill pipe or tubing which can slide over a "fish" left in the hole to wash out the space between the fish and the wall of the hole and thus free the fish which will make fishing operations easier.

Wastage

By-product that is not marketed (i.e. flare, acid gas, fuel, refrigerant).

Water column

A vertical continuum of water from sea surface to sea-bed.

Water coning

The encroachment of water in a well bore in a water-drive reservoir owing to an excessive rate of production. The water below the oil moves upward to the well bore through channels, fissures, and permeable streaks leaving the oil sidetracked and by-passed.

Water drive

A recovery process in which oil or gas is driven out of a reservoir by the pressure of underlying water.

Water drive reservoir

An oil or gas reservoir in which pressure is maintained by the influx of water as the oil and/or gas is produced. The influx of water may be a natural flow of formation water or water pumped into the reservoir via injection wells.

EnergyWeb.BIZ - providing electronic solutions that reduce total costs and increase sales.