塔里木盆地博孜-大北逆冲推覆带超深层致密砂岩地应力场模拟及分区评价

Simulation and zoning evaluation of in-situ stress field within ultra-deep tight sandstone reservoirs in thrust-nappe structures of Bozi-Dabei area, Tarim Basin

邢梓萌 李瑞雪 邓虎成 宿航 张家维 何建华 张辉 胡笑非 马顺婷

XING Zimeng LI Ruixue DENG Hucheng SU Hang ZHANG Jiawei HE Jianhua ZHANG Hui HU Xiaofei MA Shunting

1. 成都理工大学 能源学院, 成都 610059; 2. 中国石油 长庆油田分公司 工程技术监督中心, 西安 710018; 3. 中国石油 塔里木油田分公司 勘探开发研究院, 新疆 库尔勒 841000

1. College of Energy (College of Modern Shale Gas Industry), Chengdu University of Technology, Chengdu, Sichuan 610059, China; 2. Engineering Technology Supervision Center, PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710018, China; 3. Exploration and Development Research Institute, Tarim Oilfield Company, China National Petroleum Corporation, Korla, Xinjiang 841000, China

塔里木盆地博孜—大北地区白垩系致密砂岩储层是我国超深层致密砂岩气勘探开发的重点层系。受逆冲推覆构造及盐构造双重影响，该地区发育了叠瓦状褶皱构造及一系列断距大、倾角变化显著的断裂，导致地应力场分布复杂多变，难以准确预测，严重制约了该区的勘探开发进程。为揭示其应力分布规律，建立了一套适用于逆冲推覆构造特征的地应力场模拟方法，并结合储层地质特征与工程改造需求对研究区进行了应力分级分区评价。基于岩心测试、测井资料、矿场试验数据，标定了单井地应力方向和大小，系统分析了研究区地应力方向与大小的分布特征；通过探讨地应力对储层物性、脆性、工程改造难度的影响，建立了研究区应力分级评价标准；对博孜—大北地区重点开发的B1井区进行了精细三维非均质地应力场建模，明确了B1井区应力分布规律，完成了分区评价。地应力场数值模拟结果与单井地应力解释结果平均误差率小于10%，B1井区地应力方向主要为N170°—190°E，断裂附近地应力方向沿断裂走向发生20°~60°的偏转。地应力大小受埋深影响，呈现由北向南递增的趋势，背斜高点及断裂带内地应力与应力差减小；断裂级次越高，其对地应力的断裂扰动范围及强度越大。以最小主应力145 MPa、水平应力差34 MPa为界，将地应力状态由好到差分为4类：低应力差—低地应力、高应力差—低地应力、低应力差—高地应力、高应力差—高地应力。B1井区有利于压裂改造的低应力差—低地应力区主要分布于白垩系巴什组断裂上盘和构造变形高部位。

The Cretaceous tight sandstone reservoirs in the Bozi-Dabei area of the Tarim Basin are key targets for ultra-deep tight sandstone gas exploration and development in China. Influenced by thrust-nappe structures and salt structures, the region has formed imbricate folding structures and a series of faults with large displacements and varying dip angles, resulting in a complex and highly variable in-situ stress field that is difficult to predict, severely restricting exploration and development in the area. To clarify the stress distribution pattern, an in-situ stress field simulation method, suitable for the characteristics of thrust-nappe structures was developed. Moreover, a stress grading and zoning evaluation was conducted, combining with the geological and engineering modification characteristics of the reservoirs. Core testing, well logging, and mining field test data were used to calibrate the in-situ stress direction and magnitude for individual wells, and their distribution characteristics were analyzed. By examining the impact of in-situ stress on reservoir physical properties, brittleness, and engineering modification difficulty, stress grading evaluation standards for the study area were established. A detailed three-dimensional heterogeneous in-situ stress field model was constructed for well B1, a key development area in the Bozi-Dabei area, to clarify the stress distribution characteristics and conduct zoning evaluations. The average error rate between the numerical simulation results and single-well in-situ stress interpretations was less than 10%. In well B1, the in-situ stress direction was primarily between N170°-190°E, and the stress direction near the faults deflected along the fault strike with deflection angles ranging from 20° to 60°. The magnitude of in-situ stress increased from north to south with burial depth, with reduced in-situ stress and stress differences at the high point of the anticline and within the fault zone. The higher the fault order, the greater the disturbance range and intensity. Based on a minimum principal stress of 145 MPa and a horizontal stress difference of 34 MPa, the in-situ stress state was classified into four categories: low stress difference with low in-situ stress, high stress difference with low in-situ stress, low stress difference with high in-situ stress, and high stress difference with high in-situ stress. The low stress difference and low in-situ stress areas in well B1, which are favorable for fracturing modification, are mainly developed in the hanging wall of the faults in the Cretaceous Bashijiqike Formation (K1bs) and the high structural deformation areas.

国家自然科学基金面上项目(42072182)和四川省杰出青年科技人才项目(2020JDJQ0058)联合资助。

https://doi.org/10.11781/sysydz2025020296