渝东南武隆地区志留系龙马溪组页岩储层的古构造应力场模拟  

Simulation of paleotectonic stress field of Silurian Longmaxi shale reservoirs in Wulong area of southeastern Chongqing

作　　者：庞一桢 陈孔全[2] 张培先 何贵松 汤济广[1] 张斗中 高令宇 闫春明 王砚锋 Pang Yizhen;Chen Kongquan;Zhang Peixian;He Guisong;Tang Jiguang;Zhang Douzhong;Gao Lingyu;Yan Chunming;Wang Yanfeng(School of Geosciences,Yangtze University,Wuhan 430100,China;Cooperative Innovation Center of Unconventional Oil and Gas,Yangtze University,Wuhan 430100,China;East China Oil&Gas Branch,China Petroleum&Chemical Corporation,Nanjing 210000,China)

机构地区：[1]长江大学地球科学学院,武汉430100 [2]长江大学非常规油气湖北省协同创新中心,武汉430100 [3]中国石油化工股份有限公司华东油气分公司,南京210000

出　　处：《地震学报》2025年第1期73-92,共20页Acta Seismologica Sinica

基　　金：中国石化科技部项目(P21087-6)资助。

摘　　要：渝东南武隆地区志留系龙马溪组页岩储层发育,构造裂缝是页岩气运移和聚集的主控因素,而古构造应力场控制着构造裂缝的发育,对武隆地区页岩气的勘探开发具有较大影响。本文对武隆地区及周缘发育的节理进行分期配套处理,明确了武隆地区的古构造应力方向,同时通过岩石声发射实验计算得到了古构造应力的大小。在此基础上,利用ANSYS有限元软件建立了武隆地区志留系龙马溪组地层关键构造变形期的地质模型,并通过构造应力场的分析结果明确了该地区关键构造期的构造应力特征,以确定构造应力场数值模拟的边界条件,进而对构造应力场山中期和中燕山晚期,其中燕山中期的最大、最小水平主应力分别为112—194 MPa和60.93—147.99MPa,中燕山晚期的最大、最小水平主应力分别为75.67—168.32MPa和31.19—95.56MPa。模拟结果显示最大水平主应力的高值区大多集中于武隆西向斜核部、断层上盘的局部区域以及断层的拐点和端点处。页岩气有利保存区与断层上盘的距离要远于断层下盘。向斜的核部曲率越大,越易形成“Λ”型裂缝,越有利于页岩气的储集和保存,因此武隆西向斜的页岩气有利保存区优于武隆东向斜。The development of the shale reservoir within the Silurian Longmaxi Formation in the Wulong area of southeastern Chongqing is significantly affected by the superposition of multiple tectonic processes.This has led to intricate structural deformations in the region,making it imperative to analyze the principal controlling elements for shale gas preservation.Given the shale reservoir’s characteristic low porosity and low permeability,tectonic fractures play a pivotal role as the main controlling factor in the migration and accumulation of shale gas.The paleotectonic stress field determines the development of these tectonic fractures,augmenting the reservoir’s storage capacity and enhancing the connectivity among fractures.Consequently,this has a profound impact on the exploration and development of shale gas in the Wulong area.Thus,analyzing the sequence of tectonic evolution,deciphering the direction of the paleotectonic stress field,and quantitatively characterizing the features of the tectonic stress field hold substantial theoretical and practical significance for shale gas exploration and exploitation in this area.In this research paper,comprehensive field measurements were carried out on the data of conjugate shear joints in the Wulong area and its adjacent periphery.These data were then systematically classified into distinct stages and carefully matched.By leveraging the trend and superposition relationships of fold axes both within the study area and its surrounding regions,the direction of the paleotectonic stress was determined.Through the integration of geochronological data and the outcomes of rock acoustic emission experiments,the tectonic evolution process of the Wulong area was accurately reconstructed.This enabled the determination of the tectonic evolution periods and the corresponding stress magnitudes for each period,while also clarifying the key tectonic deformation period and the fracture distribution traits of the study area.Employing finite element software ANSYS,a three-dimensional geol

关 键 词：武隆地区 龙马溪组 构造演化 数值模拟 古构造应力场 

分 类 号：TE121.2[石油与天然气工程—油气勘探]