四川盆地涪陵地区页岩气层构造特征与保存评价

四川盆地涪陵页岩气田五峰组-龙马溪组含有丰富的页岩气资源，但该区经历了多期构造叠加作用，对页岩气保存条件造成了重要影响。系统研究了涪陵地区的构造特征和保存条件。该区发育北东向、北西向2组构造体系，主要形成于晚燕山期，受3套滑脱层系影响，纵向上变形特征存在差异性，可划分出3个构造形变层，中构造层变形相对强烈。将构造样式、断裂规模、剥蚀程度、裂缝密度作为构造变形的主要评价指标，可将涪陵地区平面上按构造变形分为东、西2带，西带构造变形较弱，保存条件较好。为进一步落实页岩气开发有利区，在"东西分带"认识的基础上，通过构造变形定量表征和地震预测，建立了一种涪陵地区保存条件量化评价方法。根据评价结果，在西带优选出3个有利目标区，在东带优选出2个有利目标区。 

Structural features and preservation evaluation of shale gas reservoirs in the Fuling area,Sichuan Basin

The Wufeng-Longmaxi formations in the Fuling shale gas play contain abundant shale gas resources, but the multiple tectonic superimposition had an important impact on shale gas preservation conditions in the area. We systematically studied the structural features and preservation conditions of shale gas in the Fuling area by detailed structural interpretation. There are two structural systems with NE and EW trends in the area, mainly formed in the late Yanshanian. Multi-level detachment structures were developed in the study area due to multi-phase tectonic movements. The detachment structures can be vertically divided into 3 different structural deformation layers. Structural style, fracture scale, erosion extent and fracture density were used as the main evaluation indicators for structural deformation, and the Fuling area was divided into the eastern and western belts. The structural deformation of the western belt was relatively weak, and the preservation conditions were relatively better. For further clarifying the favorable areas for shale gas development, a quantitative characterization method of preservation conditions was established by means of structural deformation characterization and reservoir prediction. According to evaluation results, three target units including Jiangdong, Pingqiao and Zilichang were selected in the western belt, and two target units including Baima and Baitao were selected in the eastern belt.