oljereservoir

An oljereservoir is a subsurface accumulation of crude oil that is contained in porous, permeable rock and trapped by an impermeable cap rock. It typically forms in sedimentary basins where organic-rich sediments mature into oil and migrate into reservoir rocks with suitable porosity and permeability. The geometry of the trap, such as folds (anticlines), fault seals, or stratigraphic pinch-outs, determines the extent of the reservoir. Key properties include porosity (how much space holds fluids), permeability (ease of fluid flow), oil viscosity, and reservoir pressure and temperature. Common reservoir rocks are sandstone and limestone; cap rocks are often shale or salt, creating a seal that prevents oil from migrating to the surface.

Extraction generally proceeds in stages. Primary recovery relies on natural pressure and gravity; secondary recovery uses injection of water or natural gas to maintain pressure and sweep oil toward production wells. When these methods leave significant oil in place, tertiary or enhanced oil recovery (EOR) methods such as steam injection, polymer flooding, or CO2 injection may be employed to improve recovery.

Estimating an oljereservoir's potential involves determining Original Oil In Place (OOIP) and remaining reserves, using geological mapping, well logs, seismic data, material balance, and reservoir simulation. Production planning addresses well spacing, artificial lift, and facility design.

The lifecycle includes exploration, appraisal, development, production, and eventual abandonment and site restoration. Oil reservoirs are a major focus of petroleum engineering and energy economics, balancing resource potential with environmental and social considerations.