Results of mercury survey test conducted over three nonanticlinal confinedtype oil and gas fields are reported in this paper. The oil-bearing reservoirs areusually buried 1200-3000m below the surface, pertaining respectively to oil andgas field of lithological confinement, that of fault block confinement and that oflithological-faulting confinement. The techniques employed include such means asdetermining gaseous mercury in soil all by negative pressure method and accu-mulative adsorption method, total mercury content in soil, adsorbed mercury insoil and mercury in water. The test results indicate that the methods used alldisplay distinct anomalies over the oil and gas fields, with their characteristicsanalogous to those of mercury vapour anomalies over metallic ore deposits. Theshape and spatial distribution of these anomalies depend largely on properties ofvapour-leading structures.The mercury vapour anomaly and electrical anomaly are contrasted relativeto oil and gas accumulations. These two sorts of anomalies sometimes coincidewith, and sometimes respectiely have some distance from, the projection of theoil and gas accumulation. This further demonstrates the effects of structural con-figuration on the anomalies.In addition,it is inferred that the location of oil andgas accumulation might be approached and determined on the basis of characte-ristics of mercury vapour aomalies and electrical anomalies.