基于“地质-工程”耦合平台的顺北断溶体储层地应力分布规律分析

顺北油田是一种碳酸盐岩断控裂缝-洞穴型储层,该类型油田通常采用水力压裂改造的方式进行开采,以提高储集体的连通性能。在水力压裂过程中,三维地应力场是影响裂缝扩展轨迹的重要因素之一。因此,研究三维地应力场的精细空间分布是水力压裂工艺需要解决的首要问题。针对裂缝-洞穴型碳酸盐岩储集体的水力压裂改造过程地应力场空间分布模拟不精细的问题,本文开发了“地质-工程”耦合平台。该平台可将地质模型转换为适用于AiFrac数值仿真软件的模型,实现了对储层三维地应力场的精细刻画。基于角点网格建立的三维地质模型,采用数值仿真软件进行三维地应力场的模拟,既可以保留储层的复杂地质构造特征,又可以利用数值仿真软件强大的计算能力,实现了地质模型和数值仿真一体化。为了验证本研究方法的有效性,本文基于前期已有的地应力测量数据,对顺北油田三维地应力场进行了分析计算。研究结果表明,断裂带对地应力场的大小和方向有显著的影响,主要表现在断裂带的规模、倾角、走向以及形态等因素在不同程度上均对地应力状态产生影响。本文提出的三维地应力场精细模拟方法可有效研究断溶体储层区域及内部、不同断裂带交汇区三维地应力场分布规律,从而为现场施工工艺参数的选择提供了重要依据。

In-situ Stress Distribution Analysis of Shunbei Fault-karst Reservoir Based on " Geology-Engineering" Coupling Platform

The Shunbei Oilfield is a fault-controlled fracture-vuggy reservoir in carbonate rocks, and hydraulic fracturing is usually used in this type of oilfield to improve the flow performance of the reservoir. In the hydraulic fracturing process, the three-dimensional in-situ stress field is one of the important factors affecting the fracture propagation trajectory. Therefore, the study of the fine spatial distribution of the three-dimensional in-situ stress field is the primary problem to be solved in the hydraulic fracturing process. Aiming at the inaccurate simulation of the spatial distribution of in-situ stress field during hydraulic fracturing of fractured-vuggy carbonate reservoirs, this paper developed the "geology-engineering" coupling platform. This platform enables the conversion of geological models into formats compatible with the AiFrac numerical simulation software, facilitating a refined characterization of the three-dimensional in-situ stress field within the reservoir. Based on the three-dimension geological model constructed using corner grid technology, the numerical simulation software is employed to simulate the three-dimensional stress field within the geological formation. This approach enables the preservation of the intricate structural features of the reservoir while leveraging the computational capabilities provided by the numerical simulation software. Consequently, the integration of the geological model and numerical simulation is achieved. In order to verify the effectiveness of this research method, this paper analyzes and calculates the three-dimensional in-situ stress field of Shunbei Oilfield based on the existing in-situ stress measurement data. The research results show that faults have a significant impact on the direction and magnitude of the in-situ stress field, mainly in that the scale, dip, strike, and shape of the faults affect the in-situ stress state to varying degrees. This three-dimensional in-situ stress field fine simulation method, as proposed in this paper, will play an important role in the study of the stress field distribution of fault-karst reservoir region, interior and intersection area of different faults, internal fractured-vuggy reservoirs and fracture zones, thus providing an important basis for the selection of on-site construction process parameters.