Abstract

Natural gas is now being sought independently of petroleum because of current market conditions. It is therefore appropriate to review our exploration methods to determine whether gas may not deserve its own specialized techniques.

Associated gas reserves will continue to share in the results of oil and gas exploration and development. However, non-associated reserves, which either have never been associated with oil or have dissociated themselves from oil, appear to justify specific study.

Natural gas may originate entirely apart from oil. Significant data on methane, the principal constituent of gas, are available from coalmines, and from metal mines cutting carboniferous sediments, as regards both origin and behavior.

Gases originating concurrently with crude oil may separate by virtue of important physical and chemical differences between the two fluids. Migration need not always be over long distances; there are many examples of commercial gas fields caused by short-range segregation.

New field discoveries in unlikely reservoirs, re-study of the old carbon-ratio idea, and information obtained from the formation of artificial gas caps by underground storage, suggest that gas-finding may involve more than normal oil-finding criteria. We may need to develop new definitions of what is a source rock and what is a reservoir. Our ideas of prospective territory and our methods of prospecting can stand review. Techniques for detection and recognition of gas reserves when drilled can stand improvement. There is adequate gas still in the ground awaiting discovery to take care of our needs for the near future, if the political and economic situation gives us an incentive to find it.