Abstract: A method is disclosed for determining the location of hydrocarbon reservoirs which comprises the steps of drilling boreholes along a linear path to a depth below the weathered zone, sampling the soil and drilling fluid found at the bottom of the boreholes for the presence of constituents, such as gaseous hydrocarbons and bacteria, indicating the presence of hydrocarbons, detonating explosive charges at the bottom of the boreholes to seismically determine the geological structure of the test area and plotting the resultant values for the constituent presence and geological structure data, with the plot having a common axis representing the linear path along which the boreholes are drilled. This method permits multiple and distinct indications of the presence of hydrocarbon reservoirs to be integrated to more uniformly and reliably predict the presence of a hydrocarbon reservoir.