in the Tupan basin show that halo positive soil absorbed gas hydroc ar bon anomalies always overlie anticlinal oil and gas reserviors ,and top p o sitive ones always overlie monoclinal oil and gas reserviors ,and their r elative shapes are similar to that of geothermal anomalies. The soil gas hydroca rbon anomalies overlying oil and gas deposits are mainly caused by vertic al hydrocarbon migration controlled subsurface temperatures