Mathematical treatment of light hydrocarbons (C₁-C₅) in the interpretation of hydrocarbon shows has been attempted by many authors. The methods so far developed have been used on specialized grids and can only be used for a few readings per grid.

A study of a large number of mud logs from many different geologic environments was conducted to compare hydrocarbon shows to various ratios of C₁-C₅ hydrocarbons. The aim of the study was to produce a method of interpretation of reservoir hydrocarbon character using C₁-C₅ gas shows that would be relatively simple to calculate, plot, and interpret. The method also had to be easily integrated with other reservoir character plots and logs such as mud logs and wireline data; hence it had to be plotted on a depth log while not losing any interpretational value.

From this study, a new method of mathematical treatment was evolved

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which can be performed at the wellsite during drilling, and by study of the relationship of the ratios, initial evaluation of the reservoir characteristics is possible.

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