渝东南彭水地区页岩储层构造应力场模拟解析

Simulation and Analysis of Tectonic Stress Field of Shale Reservoir in Pengshui Area,Southeast Chongqing

渝东南彭水地区自中新生代以来,构造变形作用复杂,精细解析古构造应力场的方向与构造演化时序,对彭水地区地应力进行定量表征,对整个彭水地区甚至整个渝东南地区页岩气的勘探和开发都具有重要的指导意义。通过对彭水地区以及周缘野外节理和断层擦痕进行统计分析处理,结合流体包裹体均一温度和磷灰石定年方法,重建研究区古构造应力场演化过程。同时,应用Abaqus对五峰组-龙马溪组页岩储层两期古构造应力场的应力值进行了定量计算。结果表明,渝东南彭水地区主要经历了两期构造作用,中燕山期,受到江南隆起SE-NW的递进扩展作用;晚燕山期-喜马拉雅期,青藏高原的隆升在研究区引起NE向的挤压。构造应力场数值模拟显示,最大主应力的高值区主要分布在向斜核部、断裂带末端和断层交汇处。应力数值模拟是研究裂缝发育程度以及深层压裂效应的基础,能够有效提高钻探的成功率。

There has been complex structural deformation in Pengshui Area of southeast Chongqing since Mesozoic and Cenozoic.The direction of paleotectonic stress field and tectonic evolution sequence are analyzed in detail,and the quantitative characterization of ground stress is of great guiding significance for the exploration and development of shale gas in Pengshui Area and even in southeast Chongqing.Through analysis and treatment of joint and fault striations in Pengshui Area and its periphery,combined with homogenization temperature of inclusions and apatite dating method,the evolution of paleotectonic stress field in Pengshui Area was reconstructed.Abaqus software is used to quantitatively calculate the stress value of paleotectonic stress field in Wufeng—Longmaxi Formations shale reservoir.The results show that Pengshui Area in southeastern Chongqing mainly experienced two stages of tectonism.In the Middle Yanshan period,it was gradually expanded by SE—NW in Jiangnan uplift.In the Late Yanshanian—Himalayan period,the uplift of Qinghai—Tibet Plateau caused NE-trending compression in Pengshui Area.The numerical simulation of tectonic stress field shows that the high value areas of maximum principal stress are mainly distributed in syncline core,end of fault zone,fault intersection.Stress numerical simulation is the basis of fracture development and deep fracturing research,which can effectively improve the success rate of drilling.