Oil recovery factor and recoverable reserves
The recovery factor as the product of the displacement, sweep and flooding efficiencies; the displacement efficiency comes from the initial and residual oil saturations of core floods. Recoverable reserves are that share of the oil in place.
K_выт = (K_н − K_но) / K_нКИН = K_выт · K_охв · K_зQ_извл = Q_геол · КИНThe displacement efficiency is the share of oil the water drives out of the flushed volume (from core); the sweep efficiency is the share of the reservoir the displacement reaches; the flushing factor allows for the swept volume not being fully flushed by the economic limit. The saturation form of the displacement efficiency assumes the same oil formation volume factor before and after the flood. The approved recovery factor comes from the field development plan; this is an estimate.
Source: A. P. Krylov's formula: RF = E_D · E_V; Craig, The Reservoir Engineering Aspects of Waterflooding, SPE Monograph 3 (1971)
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
S_oi = 1 − S_wc, as in the volumetric estimate.
From core floods after many pore volumes of water; usually 0.2–0.35.
Share of the reservoir volume the water reaches, areally and vertically; depends on heterogeneity, well pattern and mobility ratio. Usually 0.6–0.9.
Share of the swept volume flushed to residual oil by the economic water-cut limit (usually 98 %); 1 if it is not separated.
Unit converter for this formulaMass · Fraction and percent
- kg1
- t0.001
- kt1·10⁻⁶
- lb2.20462
- short ton (US)0.00110231
- K_выт — Displacement efficiency–
- Q_извл — Recoverable oil reserves–
More in Reserves and recovery
Stock tank volume of oil initially in place by the volumetric method, in million barrels.
Free gas initially in place by the volumetric method, in million standard cubic feet.
Gas dissolved in oil initially in place by the volumetric method, in million standard cubic feet.
Initial oil in place by the volumetric formula of Russian and Kazakh reserves reports (GKZ): oil-bearing area, net oil pay, porosity and oil saturation, shrinkage factor and oil density. The result is in thousand tonnes and thousand cubic metres of stock-tank oil, with the dissolved gas in place.
Results are engineering estimates from standard formulas; for design decisions check them against the codes, project documents and specialists' calculations. The formulas carried over from the original set are unchanged, and their errors are described in the notes.