Weighted Average Cost of Capital.  It is the return a firm must earn on existing assets to keep its stock price constant and satisfy its creditors and owners. It represents the "rate" at which a company "borrows" funds to support its investments and, therefore, the minimum expected rate of return for these investments. It is company and country specific and it incorporates the risk factor of the investment and/or country in question.
WACC=(group equity / operating capital) * Re + (interest-bearing liabilities / operating capital) * Rd + (provisions / operating capital) * Rd Re = after-tax cost of equity Rd = after-tax cost of debt

Well logging

The recording of information about surface geologic formations. Logging includes records kept by the driller and records of mud and cutting analyses, core analyses, drill stem tests, and electric, acoustic and radioactivity procedures.

Wet Gas

Natural hydrocarbon gas containing significant amounts o naturally liquid hydrocarbons.

Wet Stock

Fuels in a PS.


A tool for deviated drilling, basically a wedge-shaped block which is lowered into the well to divert the bit onto a chosen path at an angle to the original hole.

White Flag

Unbranded PS.

White products

Motor fuels (gasoline, naphtha, jet, kerosene, gasoil, diesel) and heating oil, i.e. products from the high or light end of the distillation process.


Wellhead pressure.
Wellhead platform.
Wellhead protector (subsea).

Wild well

A well out of control, a blowout.


A well drilled in an area where no oil or gas production exists. With modern exploration methods and equipment, about one wildcat out of seven proves productive, but not necessarily profitable.
To drill wild cat wells.
(nautical) The geared sheave of a windlass used to pull anchor chain.

Without Reserve

A term applied to a sale by auction indicating that no price is reserved (there is no minimum price).

Wobble index

An expression of the heating value of a gas flame, used in gas marketing. It is derived by dividing the gross calorific value of the fuel by the square root of its specific gravity, expressed in e.g. mega joules per cubic meter or BTU per cubic foot.