川东盆缘带武隆—白马地区构造对志留系龙马溪组页岩气的控制作用

Controlling Effect of Structure on Shale Gas of the Silurian Longmaxi Formation in Wulong—Baima Area, Eastern Marginal Zone of Sichuan Basin

四川盆地东缘是我国志留系龙马溪组页岩气勘探开发的重点地区,受多期构造运动的影响,四川盆地内部和盆缘带构造差异明显。盆地内部构造稳定且断裂欠发育,页岩气藏含气量高。研究区盆缘带初始页岩地质条件优越,但后期构造作用明显,断裂发育,目的层及上覆盖层经历抬升剥蚀,页岩气藏遭受不同程度的构造改造。以地震资料为基础,开展构造解释、断裂解析、平衡剖面恢复等工作,明确研究区的构造特征、断裂特征、构造演化过程等,探讨盆缘带构造作用对页岩气保存的控制作用。盆缘带中遭受后期构造改造作用相对较小,未被断裂切穿的向斜部位可作为今后勘探部署的重点考虑目标。

The eastern margin of the Sichuan Basin is the key area for shale gas exploration and production of the Silurian Longmaxi Formation in China.However, due to the influence of multi-stage tectonic movement, there are obvious structural differences inside the Sichuan Basin and its margin zone.Inside the basin, the structure is stable and the faults are underdeveloped, and the shale gas reservoir contains high gas.The initial geological conditions of shale along the margin zone of the basin in the study area are superior, but the later tectonic process is obvious, the fault is developed, the target layer and the overburden layer experience uplift and denudation, and the shale gas reservoir is subjected to different degrees of structural transformation.Based on seismic data, the structural interpretation, fault analysis and balanced profile restoration are carried out in this paper to clarify the structural characteristics, fault characteristics and tectonic evolution of the study area, and to discuss the control effect of tectonic action on shale gas preservation in the basin margin tectonic belt.It is considered that the syncline along the margin zone of the Sichuan Basin, which has not been cut through by faults and has suffered relatively little tectonic alteration, can be considered as a key target for future exploration and deployment.