average, about one third of an oil field’s capacity is actually extracted, leaving behind the other two thirds.
The reason being the oil is actually being held in small spaces between grains of sand of sandstone layers. No matter
what we do, there will always be about one third of the oil coating the insides of the rock, unrecoverable by any
currently known method. Researchers at MIT are trying to improve on the ratio of extracted versus left behind oil, and
point out that increasing the percent of oil harvested from worldwide oil fields by even one percentage point would be
the equivalent of adding a new oil-producing region as productive as the fields in the entire North Sea.
Standard methods to recover more oil from oil fields include injecting water, steam, or carbon dioxide, but these add
cost and therefore limit their use. Improved imaging methods can help tap oil fields. Current technologies rely on
reflection of seismic waves, and MIT computer scientists are working on better signal processing algorithms. In
addition, alternative drilling technology such as using a flame to break apart the rock could make oil drilling more
cost effective, especially for very deep wells.
[Source: Technology Review]