Xiushui Basin is a small-sized Mesozoic fault depression located in the south of Zhangqiang fault depression where good indications of oil and gas have been drilled in its volcanic reservoirs in recent years. In order to find out the boundary, internal framework and stratigraphic distribution of the Xiushui Basin, the authors conducted magnetotelluric sounding and gravity and magnetic profile measurement along two survey lines and, as a result, obtained the magnetic anomaly curves and the shallow electrical structures of the Xiushui Basin and its peripheral east and west sides. Constrained by drilling, geological and petrophysical data, the electrical structure characteristics of strata in different ages were determined, and the regional geological-geophysical model was synthetically established. The results show that the overall caprock of Xiushui Basin has low resistivity, which is apparently different from that of underlying basement. The basement of Xiushui Basin consists mainly of Upper Paleozoic strata, and the composition of the basement in the north is different from that in the south. In addition, the basement on east and west sides of the periphery of the basin consists of Precambrian metamorphic rock series. The basin has a structural pattern of two concaves and one uplift, relatively larger in the eastern sub-depression. The understanding obtained by the authors provides reliable geophysical basis for the oil and gas resources evaluation in the Xiushui Basin and Mesozoic basins in the periphery of the Songliao Basin.
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