SNF - Model EOR 101 - Petroleum Geology Systems - Brochure

A petroleum reservoir, or oil and gas reservoir, is a subsurface pool of hydrocarbons contained in po-rous or fractured rock formations. The naturally occurring hydrocarbons, such as crude oil or na-tural gas, are trapped by overlaying rock forma-tions with lower permeability. The vast majority of hydrocarbons are trapped within sedimentary rocks, formed at the earth surface though several process including weathering, precipitation and biogenic activity.