Glossary

Gas produced from a relatively impermeable reservoir rock. Hydrocarbon production from tight reservoirs can be difficult without stimulation operations. Stimulation of tight formations can result in increased production from formations that previously might have been abandoned or been produced uneconomically. The term is generally used for reservoirs other than shales. (Source: Schlumberger 2019)

A relatively impermeable reservoir rock from which hydrocarbon extraction is difficult. Reservoir rock can be tight because it has smaller grains or matrix between larger grains or because it consists mostly of silt- or clay-sized grains, which is the case for shale reservoirs. (Source: Schlumberger 2019)