地应力测井评价方法及其地质与工程意义

Well-logging evaluation of in-situ stress fields and its geological and engineering significances

赖锦 白天宇 肖露 赵飞 李栋 李红斌 王贵文 张荣虎

Jin LAI Tianyu BAI Lu XIAO Fei ZHAO Dong LI Hongbin LI Guiwen WANG Ronghu ZHANG

地应力场研究可为井网部署、油气井压裂和裂缝有效性评价等提供理论指导与技术支撑，系统归纳地应力场分析以及测井评价方法流程至关重要。总结了地应力场构成及其测井响应机理，并指出对地应力响应较灵敏的测井序列为声波时差、电阻率和成像测井。在声发射实验确定古构造应力场期次及大小的基础上，通过电阻率、声波时差测井和裂缝密度恢复最大古构造应力。现今地应力场一般从地应力方向和大小两个方面进行描述，确定地应力方向的测井方法是成像测井拾取井壁崩落和诱导缝、阵列声波测井横波分裂，获取地应力场大小的手段是水力压裂法和声发射实验。在现今地应力场描述的基础上，利用组合弹簧模型等模型或方法计算现今地应力大小，实现地应力场分析。地应力场分析结果有助于更好地开展断层性质分析、储层质量和裂缝有效性评价以及油气藏分布预测，此外在非常规油气储层压裂改造等工程领域也有较大的应用价值。

Research of the in-situ stress field can provide theoretical guidance and technical support in well design， fracture stimulation of wells and fracture effectiveness evaluation. It is crucial to summarize the in-situ stress field analysis and related loging evaluation methods. The study summarizes the components of in-situ stress field and its well-logging response mechanism， and presents the log suite consisting of sonic transit time， resistivity and image logs as the most sensitive to in-situ stress responses. The time and magnitude of paleotectonic stress field can be determined by acoustic emission experiment. The maximum paleotectonic stress magnitude can be recovered by using resistivity log， sonic transit time log and fracture density. The in-situ stress field can be described in respect of orientation and magnitude. The orientation of in-situ stress field can be determined by using the image logs to pick up borehole breakouts and induced fractures， and the array acoustic logs to derive shear wave splitting. The magnitude of the in-situ stress field can be determined through hydraulic fracturing combined with acoustic emission experiment. The in-situ stress can be calculated through models or methods including the combined spring model built on the in-situ stress field description， realizing in-situ stress field analysis. The analytical results can better help analyze fault properties， evaluate reservoir quality and fracture effectiveness， predict reservoir distribution， as well as be of practical value to the engineering fields like hydraulic fracturing of unconventional hydrocarbon reservoirs.

10.11743/ogg20230418