Enhanced Oil Recovery

Think of a nearly empty toothpaste tube. Natural pressure alone gets you the easy portion, but rolling and pressing the tube deliberately squeezes out meaningfully more. Enhanced Oil Recovery, or EOR, is that deliberate squeezing applied to a maturing oil field.

In a field's early life, natural underground pressure pushes oil up to the surface on its own. As a field matures and that pressure drops, a large share of the original oil in place can remain stuck underground unless something is deliberately injected to push it out, water, gas, or specialised chemicals, depending on the field's geology. EOR techniques can meaningfully extend the productive life of an ageing field and recover reserves that would otherwise simply be left behind.

ONGC, sitting on some of India's oldest and most mature fields, has leaned increasingly on EOR techniques to sustain production, since applying EOR to an already discovered, already developed field is often cheaper and faster than exploring for and developing an entirely new one.