基于VTI介质的页岩储层地应力预测方法及应用研究  

In-situ stress prediction method and research of shale reservoir based on VTI medium

作　　者：何成 程冰洁[1,2] HE Cheng;CHENG Bingjie(State Key Laboratory of"Oil and Gas Reservoir Geology and Development Engineering",Chengdu University of Technology,Chengdu 610059,China;Key Laboratory of"Earth Exploration and Information Technology"of the Ministry of Education,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学“油气藏地质及开发工程”国家重点实验室,成都610059 [2]成都理工大学“地球勘探与信息技术”教育部重点实验室,成都610059

出　　处：《物探化探计算技术》2024年第3期262-271,共10页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：国家自然科学基金面上基金(42074160)。

摘　　要：地应力对页岩气的采集及储层改造具有重要的指导作用,准确的地应力预测可以为优化压裂改造提供依据。页岩储层纵向上存在各向异性特征,为提高页岩储层地应力预测精度,将页岩储层等效为横向各向同性介质(VTI)模型,结合等效模型刚度矩阵参数、弹性系数及结构应变系数,开展页岩储层地应力场及应力差异比的三维模拟,预测水平主应力值、应力方向及应力差异比;并将地应力与储层裂缝、含气量相关参数相结合,分析三者之间存在的联系,并将该方法应用于试验工区龙马溪组页岩储层的地应力预测中。结果表明,基于VTI介质模型的地应力预测结果相较于基于各向同性模型的精度更高,工区应力差异比整体较大,进行压裂改造较困难,压裂不易形成较好的裂缝网络;随水平最大主应力的增大,曲率值减小,含气量存在减小的趋势。In-situ stress plays an important guiding role in shale gas collection and reservoir transformation,and accurate in-situ stress prediction can provide the basis for optimizing fracturing transformation.Longitudinal anisotropy exists in shale reservoirs.In order to improve the accuracy of shale reservoir in-situ stress prediction,shale reservoir is equivalent to transversely isotropic media(VTI)model.Combining with equivalent model stiffness matrix parameters,elastic coefficient and structural strain coefficient,a three-dimensional simulation of shale reservoir in-situ stress field and stress difference ratio is carried out to predict the value,stress direction,and stress difference ratio of horizontal principal stress.The relationship between in-situ stress and related parameters of reservoir fractures and gas content is analyzed.The method is applied to the prediction of ground stress of the Longmaxi Formation shale reservoir in the test work area.The results show that the prediction results of ground stress based on VTI medium model are more accurate than those based on the isotropic model,and the stress difference in the work area is more significant than that of the whole area.Fracturing modification is more complicated,and forming a better fracture network is difficult.With the increase of horizontal maximum principal stress,the curvature value decreases,and the gas content decreases.

关 键 词：页岩储层 VTI介质 地应力 应力差异比 裂缝 含气量 

分 类 号：TE311[石油与天然气工程—油气田开发工程]