Seismic prediction technology of shale gas sweet spots in Longmaxi Formation of south Sichuan Area

To find the sweet spots area of the exploration and development of shale gas, taking shale gas reservoirs of Longmaxi Formation of the Lower Silurian in the south of Sichuan Basin as the object of study, with the content of total organic carbon ( TOC)，brittleness and fracture development, and so on, the authors studied the key technology of seismic prediction on sweet spots area of shale gas.The combination of seismic rock physics analysis and pre-stack inversion was used to quantit atively predict TOC, and fracture development of shale reservoir was predicted by using post-stack seismic curvature technique. Then, the pre-stack inversion technolo gy was applied to identify shale with high brittleness suitable for hydraulic fracturing. Based on the prediction result of TOC content, brittleness and fracture developme nt of shale reservoirs, the 1stinterval of Longmaxi Shale was the important horizon of the development of sweet spots, which had high TOC content, good brittleness an d developing fractures. And the central, southern and southwest part of Block N201 in Changning Area in the south Sichuan Basin was the sweet spots area. Through th e set of seismic prediction technology, the area of shale gas sweet spots could be determined well and the result has provided a sound basis for the layout of mine shaf t for the exploration of shale gas.