Abstract: Provided is a method for processing measured property data, such as property data that would be generated from measurement of a property of soil gas samples collected in a geochemical survey. Property data for individual components is processed to identify whether one or more of the components corresponds to a known contaminant material. When a portion of the property data is identified as corresponding to a contaminant material, then that portion of the property data is eliminated, and remaining property data is combined to form a composite for analysis purposes. Results of the analysis may be used to determine the location for drilling exploration or test wells to test for the presence of a targeted subterranean accumulation, such as of petroleum, natural gas, coal or an environmental pollutant.