A look at the exploration history of the important oil areas of the world proves conclusively that oil and gas seeps gave the first clues to most oil-producing regions. Many great oil fields are the direct result of seepage drilling.

Seepages are most numerous in the youngest sediments, especially where they have been folded, faulted, and eroded, and on the margins of basins. Exceptions are easily explained by a comparatively calm geological history as depicted by the Gulf Coast region, West Texas, the Mid-Continent, and areas bordering stable masses.

Many seepages are the result of destruction of major accumulations of oil reservoirs. By studying seeps and the reasons for their location, geologists can see exposed on the face of the earth a great many "type oil accumulations."

Oil and gas seeps fill one of the prerequisites for a region if it is to produce oil, namely, source rocks. Since large seeps generally result from pool destruction, they also indicate reservoir rocks and structure.

Recent illustrations of the value of seeps in geologic thinking are the developments in Western Canada, the Uinta Basin of Utah, and Cuyama Valley in California.