Is There Oil Beneath My Property? First Check the Geological Structure
Accumulations of crude oil and gas require a source rock, which is an organic-rich sedimentary rock that produces petroleum as the organisms decompose following burial. Petroleum migrates from the source rock until it encounters impermeable rock or the earth's surface, where it is lost in seeps. Porous and permeable reservoir rocks allow petroleum to accumulate below impermeable layers. Geologic structures provide traps to further concentrate the accumulating petroleum. Anticlines are the best traps and the first recognized by geologists searching for oil. These structures can form "oil pools" with stacked levels of water (lowest), oil and natural gas (highest) against the impermeable rock above the reservoir.
Other types of traps have been recognized including faults, unconformities, and facies changes. Modern petroleum exploration is sophisticated, but there is no way short of drilling to determine the presence of oil. "Wildcat" wells only have a 1 in 10 chance of discovery, which explains why future oil supplies will be more difficult and costly to find.........
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Oil Trap
A set of conditions that hold petroleum in a reservoir rock and prevents its escape by migration. |
| Major types of Petroleum Traps. In all cases, impermeable rock encloses or caps the petroleum. |
