Work out reservoir volume (ooip) instantly with clear inputs, formula shown and shareable results.
Volumetric OOIP is 7758 x area in acres x net pay in feet x porosity x (1 - water saturation) / formation volume factor, giving stock tank barrels. The constant 7758 converts acre-feet to barrels. Dividing by Boi of about 1.25 converts reservoir barrels to stock tank barrels at surface conditions.
Volumetric OOIP
OOIP (STB) = 7758 x A (acres) x h (ft) x porosity x (1 - Sw) / Boi
Volumetric estimates for investment or reserve reporting require probabilistic treatment of input uncertainty and certification by a qualified reserves evaluator.
Net pay thickness and area, since both come from seismic interpretation and limited well penetrations. Porosity and saturation from logs are usually better constrained.
One acre-foot is 43,560 cubic feet, and one barrel is 5.6146 cubic feet, so an acre-foot holds 7758 barrels.