Effluent
Waste liquid, gas or vapor that results from petroleum and chemical processing.

EmTRAC
Emergency Training and Response Action Centers. Two specially designed communications and emergency vehicles operated by the Red Cross and sponsored by ConocoPhillips. EmTRAC was developed after the Oklahoma City bombing to provide fast, mobile assistance in emergencies.

Enhanced Oil Recovery
Recovery of oil or gas from a reservoir by artificially maintaining or enhancing the reservoir pressure by injecting gas, water or other substances into the reservoir rock.

Ethylene
Basic chemical used in the manufacture of plastics (such as polyethylene), antifreeze and synthetic fibers.

Exploration Drilling
Drilling carried out to determine whether hydrocarbons are present in a particular area or structure.

Exploration License
A license to explore for oil or gas in a particular area issued to a company by the governing state.

Exploration Phase
The phase of operations in which a company searches for oil or gas by carrying out detailed geological and geophysical surveys, followed up where appropriate by exploratory drilling in the most promising places.

Exploration Rig
A structure used to carry the equipment needed for exploratory drilling. See semi-submersible rig.