The Williston basin, covering parts of Montana, North Dakota, and South Dakota, is one of the largest and most active petroleum provinces in the Rocky Mountains. Since the discovery of gas on Cedar Creek anticline in 1913 and oil in 1950, the basin has been the scene of several periods of intense drilling activity, the most recent beginning in the mid-1970s and continuing to the present. Early exploration in the basin centered around structural features with surface expression, such as Cedar Creek anticline, and shallow objective zones. As deeper Paleozoic zones were proven productive on these structures, seismic techniques became essential for defining structural leads with no surface expression. More detailed seismic data and more sophisticated processing techniques wer necessary to define deeper and more subtle structures in remote parts of the basin. Existing technology was rapidly adapted by the petroleum industry to explore for these deeper traps.

Although a mature basin by some standards, the Williston basin still contains vast areas that are virtually unexplored. Intense competition by the industry and escalating land acquisition costs indicate that these parts of the basin will be the center of exploration activity in the future. The reserve potential of these areas should be at least as large as the proven reserves in the basin to date. Of equal importance is the exploitation of the more mature parts of the basin, including new pay zones.

Future exploration in the Williston basin must incorporate new exploration techniques and new exploration philosophies in the evaluation of new pay zones and unexplored parts of the basin.

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