Identification and petroliferous analysis of the sublacustrine fan sand bodies in SQ3 transgressive system tract of Shuangnan Structure

A set of sandy reservoirs with high oil abundance developed in the SQ3 water-bearing lacustrine mudstone deposition of Shuangnan structure. However, the productivity difference between wells is large,incomplete Bauma sequence can be seen in the core, through comprehensive logging facies and seismic facies analysis, it is determined to be the lacustrine fan sedimentary sand body. Under the control of five-level sequence lattice, the sensitive amplitude attribute and zero crossing point attribute are selected and the distribution boundary of sand body is characterized qualitatively by combining the seismic reflection characteristics of sublacustrine fan. The distribution range of sand body is quantitatively characterized by well logging constrained reservoir inversion technique. The results show that the sand bodies in sublacustrine fan are divided into two stages, in which the supply channel of the sublacustrine fan and the braided channel of the middle fan are well developed and well connected, and they are medium-porosity and mediumpermeability reservoirs, and they are the dominant reservoir in the area. The hydrocarbon abundance and the productivity in the single well are better than that of in other facies belts. According to the regional structural characteristics of Shuangnan structure, it can be divided into three kinds of favorable target areas.