Reserves Estimate Calculator

Work out reserves estimate instantly with clear inputs, formula shown and shareable results.

About Reserves Estimate Calculator

Reserves are the recoverable fraction of oil in place less what has already been produced: EUR = OOIP x recovery factor, and remaining reserves = EUR - cumulative production. Depletion percentage shows how far through its life the field is, which drives investment and abandonment planning.

Formula

Reserves

EUR = OOIP x recovery factor; remaining reserves = EUR - cumulative production

Worked example

With the default values below, Reserves Estimate Calculator returns Remaining Reserves of 40.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Original Oil In Placeminimum 0 million bbl: 250 million bbl
Recovery Factoraccepts 0.01–100 %: 32 %
Cumulative Produced To Dateminimum 0 million bbl: 40 million bbl
Oil Priceminimum 0 per bbl: 78 per bbl

Results

Remaining Reserves: 40.000
Estimated Ultimate Recovery: 80.000
Field Depletion: 50.00%
Gross Revenue Potential: $3,120,000,000

Step by step

1Values used
2Reserves
3Remaining Reserves= 40.000
4Estimated Ultimate Recovery= 80.000
5Field Depletion= 50.00
6Gross Revenue Potential= 3,120,000,000

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Reserves classification and reporting must follow the applicable framework such as PRMS or SEC rules and be certified by a qualified reserves evaluator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Reserves classification and reporting must follow the applicable framework such as PRMS or SEC rules and be certified by a qualified reserves evaluator.

Frequently Asked Questions

What is the difference between resources and reserves?

Reserves are commercially recoverable with existing technology under current economics and require a defined development plan. Contingent and prospective resources lack one or more of those conditions.

Why do reserves change without new drilling?

Because they depend on price, cost and technology as much as on geology. A price fall can move barrels from reserves to contingent resources with no change in the reservoir.