GCHD technology is mainly used to predict the geochemical properties of the reservoir in depth (oil, condensate or gas etc.). It applies the proprietary acid extraction technique with gas chromatographic analysis to detect the concentration of sorbed soil gas (C1-C5) in surface soil or sediments. The origin and composition of the migrated (or reservoired) hydrocarbons can be inferred from the hydrocarbon ratios and isotopic analysis.