What is enhanced oil recovery? A practitioner's answer.

When an oil well is first drilled, underground pressure pushes oil to the surface on its own. This is called primary recovery, and it typically extracts only 10–20% of the oil in the reservoir.

As pressure falls, operators pump water or gas into the ground to push more oil toward the wells — secondary recovery. That brings the total to roughly 20–40%. The rest — often more than half of the oil ever discovered — stays trapped in the rock.

Enhanced oil recovery (EOR), sometimes called tertiary recovery, is the set of techniques used to extract that remaining oil. Instead of just pushing the oil, EOR changes the physics and chemistry of the reservoir so trapped oil can flow.

Each method fits a different reservoir. Thermal suits heavy oil; gas injection suits light oil near a CO₂ source; chemical EOR suits the enormous population of midlife-to-mature waterflooded fields — the fields the world already relies on.

Most of the world's oil comes from fields discovered decades ago, and their output declines every year. Discovering new fields is slow, capital-heavy and increasingly rare. EOR offers a different path: produce more from fields that already exist, with infrastructure already in place.

The prize is large. Raising recovery from a mature field by even a few percentage points can mean millions of additional barrels — from an asset the operator already owns.

EOR adds cost per barrel: chemicals, injection equipment, monitoring and time. Whether a project works comes down to a handful of variables:

• Oil price. Every EOR project has a breakeven oil price. Below it, the extra barrels don't pay for the chemicals.
• Water cut. Mature wells often produce far more water than oil. Chemical EOR can sharply reduce water production — cutting handling costs while raising oil output.
• Reservoir fit. Temperature, salinity, rock type and oil viscosity all decide which chemistry works, and how much incremental oil to expect.
• Cost of the alternative. The right comparison is usually EOR versus drilling a new well. In a mature field, EOR frequently wins on cost per barrel — and avoids new surface disturbance.

This screening — price, water cut, reservoir fit, breakeven — is exactly the analysis Tigbourne Capital runs before committing capital. Our Tigbourne OFI platform models these economics field by field.

Tigbourne Capital invests primarily in chemical EOR deployments with international and national oil companies. Across our active structures, CEOR has doubled production from trapped oil in treated wells while cutting CO₂ per barrel by roughly a third — because producing more from an existing field avoids the emissions of finding and developing a new one.

We work alongside the world's leading chemical and oilfield service companies. You can read more about the technology, our track record, or the companies active in EOR.