A Search for Controls on the Distribution of Oil Seeps in the Minibasin Provinces

In this research, published literature is used to compile information on over one thousand natural hydrocarbon occurrences across the world, focusing primarily on oil seeps in the minibasin provinces and the structural features which control their distribution. Data was collected on 94 submarine oil seeps in the Gulf of Mexico, the principal minibasin province, to better understand the role of minibasins as a primary mechanism in the process of oil seepage. Of the 57 natural oil seeps in the US Gulf of Mexico, 39 are found along the edges of minibasins, or sub-circular, sedimentary basins bounded on all sides by emergent, salt diapirs. Strata at the edges of minibasins are usually steeply dipping and faulted along a rotated, normal fault that forms the upper edge of the rising diapir. The steep dip of the bedding and presence of faults provides conduits for the rise of oil and the predominance of natural seeps in this setting. Research is currently being done on the potential for hydrocarbon exploration in other minibasin provinces such as offshore Angola, which is a passive margin similar to the Gulf of Mexico, with an abundance of natural oil seeps.