四川盆地SN地区二维地震勘探页岩气有利区带优选

Favorable Blocks Optimization of Shale Gas Based on 2D Seismic Surveys in SN, Sichuan Basin

摘要: 四川盆地志留系龙马溪组页岩气资源较为丰富，地质条件较好，如何在利用地质成果进行选区的基础上，准确找到可以具有商业开发价值的页岩气区块尤为重要。四川盆地二维地震资料丰富，利用二维地震资料编制二维地震资料品质评价成果、二维地震反射构造成果、二维地震反射埋深成果、二维地震断层分级评价成果以及二维地震优质页岩预测成果。通过地震资料所得各项成果的分析，要求地震资料品质较好、地层倾角较平缓(地层倾角小于30度)、离断层分级评价成果中的各级断层有一定的距离(离一级断层大于1.5 km，离二级断层大于0.7 km)、离剥蚀线的距离较远(大于8 km)、优质页岩的埋深情况适中(1500~4500 m)以及优质页岩的厚度较厚(大于20 m)，进行有利区域的优选，实现页岩气的二维地震勘探有利区域的优选工作。再在二维地震勘探页岩气有利区带优选的有利区内实现页岩气的有效的商业开发，研究表明SN地区CN区块的JW向斜、LC向斜、SL向斜等具有较好的勘探开发潜力，目前JW向斜区块页岩气的开发进入实质性开发阶段，已成为国家级页岩气示范区。

Abstract: The Silurian Longmaxi Formation in the Sichuan Basin is rich in shale gas resources and has good geological conditions. It is especially important to find favorable shale gas blocks that can be of commercial development value based on geological results. Two-dimensional seismic data in the Sichuan Basin is abundant, which can be used to deliver 2D seismic data quality evaluation results, 2D seismic reflection structural results, 2D seismic reflection buried depth results, 2D seismic fault classification evaluation results, and 2D seismic high-quality reservoir prediction results. The reservoir evaluation and the favorable area selection have been done based on the results above. The favorable areas of the 2D seismic shale gas exploration should have good seismic data quality and small formation dip angles (less than 30 degrees). They should be away from the faults (more than 1.5 km from the first-class faults and more than 0.7 km from the second-class faults) and the denudation line (greater than 8 km), with moderate buried depth (1500~4500 m) and shale formation thickness (more than 20 m). The effective commercial development of shale gas is employed in the favorable areas. The research shows that the JW syncline, LC syncline and SL syncline of the CN block in the SN area have better exploration and development potential. Currently, the JW syncline block, which is a national shale gas demonstration block now, has entered the stage of the field development.