Oil Reserves
The total estimated amount of oil in an oil reservoir, including both producible and non-producible oil, is called oil in place. However, because of reservoir characteristics and limitations in petroleum extraction technologies, only a fraction of this oil can be brought to the surface, and it is only this producible fraction that is considered to be reserves. The ratio of producible oil reserves to total oil in place for a given field is often referred to as the recovery factor. Recovery factors vary greatly among oil fields. The recovery factor of any particular field may change over time based on operating history and in response to changes in technology and economics. The recovery factor may also rise over time if additional investment is made in enhanced oil recovery techniques such as gas injection, surfactants injection, water-flooding, or microbial enhanced oil recovery.
Based on data from OPEC at the beginning of 2011 the highest proved oil reserves including non-conventional oil deposits are in Venezuela (20% of global reserves), Saudi Arabia (18% of global reserves), Canada (13% of global reserves), Iran (9%).
Because the geology of the subsurface cannot be examined directly, indirect techniques must be used to estimate the size and recoverability of the resource. While new technologies have increased the accuracy of these techniques, significant uncertainties still remain. In general, most early estimates of the reserves of an oil field are conservative and tend to grow with time. This phenomenon is called reserves growth.
Many oil-producing nations do not reveal their reservoir engineering field data and instead provide unaudited claims for their oil reserves. The numbers disclosed by some national governments are suspected of being manipulated for political reasons.
Read more about Oil Reserves: Classifications, Estimation Techniques, Reserves Growth, Estimated Reserves By Country, OPEC Countries
Famous quotes containing the words oil and/or reserves:
“Friendship and money: oil and water.”
—Mario Puzo, U.S. author, screenwriter, and Francis Ford Coppola, U.S. director, screenwriter. Michael Corleone (Al Pacino)
“While you are nurturing your newborn, you need someone to nurture you, whether it is with healthful drinks while you’re nursing, or with words of recognition and encouragement as you talk about your feelings. In this state of continual giving to your infant—whether it is nourishment or care or love—you are easily drained, and you need to be replenished from sources outside yourself so that you will have reserves to draw from.”
—Sally Placksin (20th century)