A type of stratigraphic trap. The termination, by thinning or tapering out ("pinching out"), of a reservoir against a nonporous sealing rock creates a favorable geometry to trap hydrocarbons, particularly if the adjacent sealing rock is a source rock such as shale.

Exploration well drilled outside the proven limits of an oil field, specifically to test whether the production area can be expanded.

In this glossary you will find the basic definition of terms often used in the context of related Hydrocarbon Exploration and Production activities.

Proven reserves (also known as P90).

2D (two dimensional) seismic is an acoustic measuring technology which generates a 2D cross-section of the subsurface of the earth and is used primarily when initially reconnoitering for the presence of oil or gas reservoirs. Acoustic energy is usually provided by the detonation of explosive charges or by large vibrating trucks.

3D seismic is shot similar to 2D, except the “shotpoints” are much closer together and are laid out on a grid, instead of in a straight line. The geophones that receive the reflected sound waves are also laid out in a grid. These technology is good at showing structural traps, but not ideal for showing stratigraphic traps.

Proven reserves + Provable reserves + Possible reserves.

Time-lapse of 3-D and is used once production has begun to see how the production flows are changing in the reservoir.

The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water. If its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks.

Exploration well drilled near a well already in production as part of an appraisal campaign, which is carried out to determine the physical extent and likely production potential of a field.