库车坳陷依南-吐孜地区下侏罗统阿合组砂岩构造裂缝分布预测

Structural Fracture Distribution and Prediction of the Lower Jurassic Ahe Formation Sandstone in the Yinan-Tuzi Area, Kuqa Depression

塔里木盆地库车坳陷依南一吐孜地区下侏罗统阿合组低孔低渗砂岩是该区主要的储集层，其中构造裂缝是油气渗透的重要通道和储集空间。在声发射地应力测量和岩石力学参数测试的基础上，考虑断层对构造裂缝形成的影响，采用三维有限元法对库车坳陷依南一吐孜地区主要裂缝形成期的古构造应力场进行数值模拟，通过岩心构造裂缝发育程度的约束，预测出库车坳陷依南一吐孜地区阿合组构造裂缝的分布规律。结果表明，在依奇克里克背斜带和依南2井附近构造裂缝最为发育，构造裂缝的密度在1．4m-1以上，向东吐孜地区以及依南2井南部地区，构造裂缝密度逐渐减小，在0～0．4m-1范围内。通过本次研究可以为该区的构造裂缝评价和油气勘探提供新的地质依据和指导。

The Lower Jurassic Ahe Formation sandstone characterized by low porosity and low permeability is the main reservoir in the Yinan-Tuzi area of the Kuqa Depression, within which the well-developed structural fractures serve as important migration pathways and accumulation spaces. On the basis of acoustic emission and rock mechanics parameter testing, considering the influence of faults on the fracture forming, we simulate the main fracture forming period paleostress field and predict the distribution of structural fractures with the constraints of cores using 3D finite element method. The simulation results show that the Yiqikelike anticlinal zone and the Well Yinan 2 area are the most favorable areas for structural fractures, with density 〉1.4 m-1. The structural fracture density decreases gradually towards the Tuzi area and south of Well Yinan 2 area, varying in the range of 0 to 0.4 m-1. The present study results can provide us new geological evidence for the fracture development evaluation, and reservoir prospecting and exploitation in the area.