Electrical resistivity imaging in Shibaozhai area using magnetotelluric sounding: enlightenment for hydrocarbon reservoirs on the eastern edge of the Sichuan basin

The Shibaozhai area is located in the northeast Sichuan Basin in Southwest China. In recent years, oil and gas reservoirs with abundant reserves have been discovered in nearby areas. Six magnetotelluric (MT) survey lines were arranged to investigate the deep geoelectrical structures and the hidden oil- and gas-controlled faults along the eastern Kaijiang-Liangping trough and the Dachiganjing tectonic belt in this area. The MT sounding data for 181 sites, covering an area of 15 x 6 km, was collected. Two-dimensional transverse magnetic (TM) mode inversion of the data revealed four geoelectric layers with a total thickness of about 10 km. A low resistivity layer that is 4 km thick is discovered in the middle of the exploring area. The combination of faults within the study area represents a NE direction thrust fault system, which was displaced by NW direction faults. The regional geological structures play a signifi cant role in controlling hydrocarbon and gas accumulation. The results of this study could be valuable in analyzing the geological structure of hydrocarbon reservoirs in this area and can be extended to an exploration area in the boundary of a basin.

Automated summary

The MT sounding survey in the Shibaozhai area revealed the deep geoelectrical structures and hidden oil- and gas-controlled faults. The regional geological structures play a significant role in controlling hydrocarbon and gas accumulation.