Recovery Increase (EOR recovery increase)

Recovery Increase quantifies the incremental crude oil production achieved when Enhanced Oil Recovery (EOR) techniques — most commonly CO₂ injection — are applied to mature reservoirs that have exhausted primary (natural drive) and secondary (water flooding) recovery methods. Globally established field data show that CO₂-EOR typically adds 7–15% to total reservoir oil recovery, measured as a percentage of original oil in place (OOIP). For a field that recovered 35% of OOIP through primary and secondary methods, CO₂-EOR can take total recovery to 42–50%.

The recovery increase varies with reservoir characteristics:

• Oil gravity — lighter oils (above 25° API) respond better to CO₂ miscibility than heavy oils
• Reservoir depth and pressure — minimum miscibility pressure of 10–15 MPa requires reservoirs deep enough to maintain it
• Permeability and heterogeneity — uniform sandstones give higher sweep efficiency than fractured carbonates
• CO₂ utilisation ratio — typical projects inject 4–10 standard cubic feet of CO₂ per barrel of incremental oil recovered

For Indian fields where CO₂-EOR pilots have been studied — Mangala in Rajasthan, Gandhar in Gujarat, and Ankleshwar — recovery increases of 8–12% are considered realistic based on reservoir modelling. At a barrel price of US$70 and recovery of 10 million additional barrels over a field's remaining life, the gross revenue uplift exceeds US$700 million, which makes economic sense even at significant CO₂ procurement costs.

For CBG operators eyeing the EOR market as a CO₂ offtake, the relevant economics work in reverse. Oil companies will pay roughly ₹3,000–6,000 per tonne for delivered EOR-grade CO₂, valuing it against the incremental oil recovered. The trade-off is logistical: CBG plants are typically located in rural feedstock-producing areas, far from oilfields, and the cost of liquefying and trucking CO₂ over 300–800 km can consume most of the value. Only CBG plants located within pipeline distance of EOR projects, or with co-located CO₂ industrial offtakers, can capture the recovery-increase upside.