Petroleum geology of the state of Washington

This report describes the potential petroleum resources of Washington State as recently summarized in the 1995 U.S. Geological Survey National Assessment of Oil and Gas Resources. Eight conventional petroleum plays, three coal-bed gas plays, and two continuous-type gas plays are defined and characterized. Of these plays, the potential for significant petroleum accumulations appears greatest in the Columbia Plateau region of eastern Washington. Potential accumulations in western Washington are smaller but could have local economic significance. The absence of high-quality petroleum source rocks is probably the most important factor limiting development of large accumulations.