how enhanced oil recovery works
enhanced oil recovery techniques are complex and expensive and therefore are employed only when the primary and secondary recovery techniques have exhausted their usefulness indeed depending on factors such as the cost of oil it may not be economical to employ eor at all in those cases oil and gas might be left in the reservoir because it is simply not profitable to extract the remaining amounts three main types of eor techniquesin the first type of technique gases are forcefully injected into the well in a way that both forces the oil to the surface and reduces its viscosity the less viscous the oil the easier it flows and the more cheaply it can be extracted although various gases can be used in this process carbon dioxide co2 is used most often this specific use of carbon dioxide likely could continue or even increase in the future as recent advances make it possible to transport co2 in the form of foams and gels to some this could be a significant improvement as it would allow co2 injections to be utilized in areas far removed from naturally occurring carbon dioxide reservoirs on the other hand there are grave concerns about the continued use of carbon dioxide because of its harmful effects on the environment currently most countries are seeking alternative modes of energy that are more sustainable than co2 other common eor techniques include pumping steam into the well in order to heat the oil and make it less viscous similar outcomes can be achieved through so called fire flooding which involves lighting a fire around the periphery of the oil reservoir in order to drive the remaining oil close to the well finally various polymers and other chemical structures can be injected into the reservoir to reduce viscosity and increase pressure although these techniques are often prohibitively expensive using enhanced oil recovery methodspetroleum companies and scientists look to eor for its potential to prolong the life of wells in proven or probable oil fields proven reserves are those with a greater than 90 chance that oil will be recovered and probable reserves have a more than 50 chance of recovering petroleum unfortunately eor techniques can produce negative environmental side effects such as causing harmful chemicals to leak into the groundwater one recent technique that might help reduce these environmental risks is called plasma pulsing developed in russia plasma pulse technology involves radiating oil fields with low energy emissions thereby lowering their viscosity much like conventional eor techniques because plasma pulsing does not require injecting gases chemicals or heat into the ground it may prove to be less environmentally harmful than the other current methods of oil recovery 