Glossary

E-log

logs run on a wireline into the borehole. Originally 'Electric' Log but now refers to all such logs (eg. Neutron, sonic, etc).

Edge water

water underlying and/or marginal to an oil or gas reservoir.

Enhanced oil recovery (EOR)

a process whereby oil is recovered other than by the natural pressure in the reservoir; see secondary recovery, tertiary recovery.

Equity crude

the proportion of crude oil to which a producing company is entitled as a result of its financial contribution to a project.

Ethane

the saturated hydrocarbon (alkane) with two carbon atoms in its molecule (C2H6); the second member of the paraffin series -a gas under normal conditions.

Ethene (ethylene)

the simplest member of the alkene series, containing two carbon atoms connected by a double (unsaturated) bond (C2H4); an important raw material in the chemical and plastics industries

Exploration Drilling

drilled to find and produce oil or gas reserves not classified as proved, to find a new reservoir in a field previously found to be productive of oil or gas in another reservoir or to extend a known reservoir

Exploration licence

a licence to explore for oil or gas in a particular area issued to a company by a governing state.

Exploration phase

the phase of operations in which a company searches for oil and gas by carrying out detailed geological and geophysical surveys followed up where appropriate by exploratory drilling.

Exploration rig

a structure used to carry the equipment needed for exploratory drilling; see jack-up, semi-submersible and drill ship.