Natural gas now is being sought independently of petroleum because of current market conditions. It is therefore appropriate to review exploration methods to determine the need for specialized gas-finding techniques.

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

Natural gas may originate entirely apart from oil. Significant data concerning both the origin and behavior of methane--the principal constituent of gas--are available from coal mines and from metal mines cutting carboniferous sediments.

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

New field discoveries in unlikely reservoirs, restudy 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. New definitions may be needed of what is a source rock and what is a reservoir. Ideas of prospective territory and methods of prospecting can stand review. Techniques for detection and recognition of gas reserves when drilled need improvement. There is adequate gas in the ground awaiting discovery to take care of the needs for the near future, if the political and economic situation provides an incentive to find it.