复杂断块区构造应力场分析及应用

Analysis and Application of Tectonic Stress Field in Complex Fault-Block

永3断块区位于东营凹陷东北部永安镇油田,其沙二段油藏为典型的复杂断块油藏,发育较多低序级断层。复杂断块区低序级断层地震解释存在多解性,在地震解释后应进行合理性分析。通过构造解析,在确定低序级断层发育时期和构造作用背景的基础上,开展了古构造应力场的数值模拟研究。以岩石破裂准则为依据,通过最小主应力、最大与最小主应力差值分析了低序级断层的优势发育部位,用平面剪应力分析了低序级断层的优势走向,用剖面剪应力分析了低序级断层的优势视倾向。通过精细地震解释,该复杂断块区断层描述较合理,可用于指导生产实践,同时,对同类型复杂断块区断层分布规律研究起到一定的指导作用。

Fault-block Yong3 in Yonganzhen Oilfield is located in the northeast of Dongying Sag and the Sha2 reservoir in this fault-block is considered as a complex fault-block reservoir with well-developed low-grade faults. The seismic interpretation of low-grade faults in complex fault-block is characterized by multi-solution,which needs further analysis after interpretation. Based on the development period of low-grade faults and tectonic setting,the numerical simulation of paleostructure stress field is carried out by structure analysis. According to the rock fracture criteria,the minimum principal stress and the difference in maximum and minimum principal stress are used to analyze the favorable parts with well-developed low-gradefault. The plane shear stress is used to analyze the favorable strike of low-grade fault. The cross-section shear stress is used to analyze the favorable trend of low-grade fault. The fine seismic interpretation shows relatively reasonable fault characterization for this fault-block,which can be used in field practice. In addition,this research could provide certain guidance for the identification of fault distribution in similar complex fault-blocks.