庞一桢, 陈孔全, 张培先, 何贵松, 汤济广, 张斗中, 高令宇, 闫春明, 王砚锋. 0: 渝东南武隆地区志留系龙马溪组古构造应力场模拟研究. 地震学报. DOI: 10.11939/jass.20230137
引用本文: 庞一桢, 陈孔全, 张培先, 何贵松, 汤济广, 张斗中, 高令宇, 闫春明, 王砚锋. 0: 渝东南武隆地区志留系龙马溪组古构造应力场模拟研究. 地震学报. DOI: 10.11939/jass.20230137
YiZhen PANG, KongQuan CHEN, PeiXian ZHANG, GuiSong HE, JiGuang TANG, DouZhong ZHANG, LingYu GAO, ChunMing YAN, YanFeng WANG. 0: Paleotectonic Stress Field of Silurian Longmaxi Formation in Wulong area of southeastern Chongqing. Acta Seismologica Sinica. DOI: 10.11939/jass.20230137
Citation: YiZhen PANG, KongQuan CHEN, PeiXian ZHANG, GuiSong HE, JiGuang TANG, DouZhong ZHANG, LingYu GAO, ChunMing YAN, YanFeng WANG. 0: Paleotectonic Stress Field of Silurian Longmaxi Formation in Wulong area of southeastern Chongqing. Acta Seismologica Sinica. DOI: 10.11939/jass.20230137

渝东南武隆地区志留系龙马溪组古构造应力场模拟研究

Paleotectonic Stress Field of Silurian Longmaxi Formation in Wulong area of southeastern Chongqing

  • 摘要: 摘要 渝东南武隆地区志留系龙马溪组页岩储层发育,区内构造变形复杂,因此对构造演化时序和古构造应力场的方向进行精细解析,武隆地区构造应力场的特征进行定量表征,对页岩气的勘探和开采具有重要指导意义。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,影响了武隆地区页岩气的勘探开发。本文通过对武隆地区及周缘发育节理进行分期、配套处理,进行详细观测确定古构造应力的方向,古构造应力大小的计算可以通过岩石声发射实验进行。在此基础上,利用ANSYS有限元软件建立武隆地区志留系龙马溪组关键构造变形期的地质模型,通过构造应力场的分析结果确定边界条件,并进行构造应力场数值模拟。结果表明:武隆地区受雪峰陆内造山运动的传导作用,主要构造变形期为中燕山中期和中燕山晚期,区内中燕山中期水平最大主应力为112-194Mpa,水平最小主应力为60.93-147.99Mpa;中燕山晚期水平最大主应力为75.67-168.32Mpa,水平最小主应力为31.19-95.56Mpa。模拟结果显示最大主应力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、端点处。页岩气的优势保存区与断层上盘的距离要远于断层下盘。向斜核部曲率越大,越易形成“Λ”型裂缝,有利于页岩气的储集和保存,因此武隆西向斜的页岩气富集和保存区优于武隆东向斜。研究古构造应力场特征,是研究构造裂缝发育程度和深层压裂效应的基础,是影响高产的重要因素。

     

    Abstract: Abstract: The development of the Silurian Longmaxi Formation shale reservoir in Wulong area of southeast Yudong has complex tectonic deformation, so the tectonic evolution time sequence and the direction of paleotectonic stress field are finely analyzed, and the characteristics of tectonic stress field in Wulong area are quantitatively characterized, which has important guiding significance for shale gas exploration and exploitation. Tectonic fractures are the main controlling factors of shale gas transport and accumulation, while paleotectonic stress fields control the deve lopment of structural fractures, which affects the exploration and development of shale gas in Wu- long area. In this paper, the direction of paleotectonic stress was determined by staging and supp- orting treatment of the developmental joints in Wulong area and its peripheral margin, and the cal- culation of paleotectonic stress could be carried out by rock acoustic emission experiments. On this basis, ANSYS finite element software is used to establish a geological model of the key tectonic deformation period of the Silurian Longmaxi Formation in Wulong area, and the boundary condit- ions are determined by the analysis results of the tectonic stress field, and the numerical simulatio- n of the tectonic stress field is carried out. The results show that the main tectonic deformation pe- riod in Wulong area is the middle period of Zhongyanshan and the late Zhongyanshan period, the maximum horizontal principal stress in the middle period of Zhongyanshan is 112-194 Mpa , the minimum horizontal principal stress is 60.93-147.99 Mpa, and the maximum horizontal principal stress is 75.67-168.32Mpa and the minimum horizontal principal stress is 31.19- 95.56 Mpa. The simulation results show that most of the regions with high maximum principal stress values are concentrated in the western oblique core of Wulong, the local area of the upper disk of the fault, and the inflection point and end point of the fault. The distance between the dominant preservation zone of shale gas and the fault upper disk is farther than that of the fault lower disk. The larger the curvature of the oblique nucleus, the easier it is to form "Λ" type fractures, which is conducive to the storage and preservation of shale gas, so the shale gas enrichment and preservation area of Wulong's west-inclined slope is better than that of Wulong's east-inclination. Studying the chara- cteristics of paleotectonic stress field is the basis for studying the development degree and deep fracturing effect of tectonic fractures, and is an important factor affecting high yield.

     

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