ABSTRACT
Petroleum usually occurs in sedimentary basins, which are depressions in the earth’s surface that are ‰lled by thick sediment cover. The occurrence of petroleum in the basin requires a source rock, usually a mudrock or shale, rich in organic matter. The source rock must be buried deep enough so that temperature and time can cause the organic matter to mature into petroleum. The petroleum, thus generated, migrates from the source bed to accumulate within a porous and permeable reservoir called traps.
