Residual oil saturation is oil saturation that can not be produced from an oil reservoir from gas or water displacement. It is usually considered the immobile oil saturation after conventional (gas or water displacement).

1) It is can be based on result from a laboratory test. A core sample (rock sample in the shape of a cylinder) is taken from a reservoir is first saturated with oil and then displaced (pushed out) with water or gas. The test is ended when no more oil can be produced from this core. The oil that can not be pushed out and remains in the core is termed "residual oil." The residual oil to gas displacement may be different from the residual oil from water displacement. The residual oil in this case is a laboratory estimate.

2) It can be based measurement made in a well. If a zone in a reservoir is producing only gas or water, it may be assumed that the oil has been completely displaced. In this case, special tools are lowered in the well and the oil saturation is determined. The residual oil in this case is a field estimate.

There are a number of unconventional means (or enhanced recovery techniques) to displace the residual oil. A common means is injection of carbon dioxide or an enriched gas at high pressures which can partially dissolve the residual oil.

Residual oil saturation is oil saturation that can not be produced from an oil reservoir from gas or water displacement. It is usually considered the immobile oil saturation after conventional (gas or water displacement).

1) It is can be based on result from a laboratory test. A core sample (rock sample in the shape of a cylinder) is taken from a reservoir is first saturated with oil and then displaced (pushed out) with water or gas. The test is ended when no more oil can be produced from this core. The oil that can not be pushed out and remains in the core is termed "residual oil." The residual oil to gas displacement may be different from the residual oil from water displacement. The residual oil in this case is a laboratory estimate.

2) It can be based measurement made in a well. If a zone in a reservoir is producing only gas or water, it may be assumed that the oil has been completely displaced. In this case, special tools are lowered in the well and the oil saturation is determined. The residual oil in this case is a field estimate.

There are a number of unconventional means (or enhanced recovery techniques) to displace the residual oil. A common means is injection of carbon dioxide or an enriched gas at high pressures which can partially dissolve the residual oil.

Bio-pesticides are derived as residual bi-products after fermentation of the jatropha crude oil for biodiesel production

petroleum, residual, crude, bitumen, asphalt among others.

Lakes which are made by residual rocks which are left after weathering and erosion and form the residual lakes.