Three-dimensional electromagnetic method in shallow surface exploration in complex piedmont belt

Abstract

Abstract In the complex piedmont area, the quality of seismic data is generally poor, and it is difficult to build the shallow velocity model, which leads to the inaccurate determination of the stratigraphic and structural positions. The combination of seismic and non-seismic exploration is an effective way for oil and gas exploration in complex piedmont belt. In the northwest of Sichuan Province, the joint exploration of three-dimensional audio-magnetotelluric (AMT) and transient electromagnetic (TEM) is carried out. The transient electromagnetic data is used as static correction for audio-magnetotelluric data, and the AMT data is used to detect the shallow surface structure within 1.5km buried depth. The three-dimensional geoelectric model of the study area is obtained by using AMT three-dimensional inversion, and the geological structure interpretation is carried out by combining well logging with the statistical data of rock physical properties, which provides a basis for seismic building the shallow surface model.