非均质致密油藏三维地应力场数值模拟评价——以渤南油田Y176块为例

Numerical Evolution of the Three-Dimensional Stress Field of the Heterogeneous Tight Reservoir—A Case Study of Y176 Area’ Bonan Sag

地应力是致密油气藏高效勘探开发的重要基础参数,渤南油田Y176区块致密油藏沙四上亚段断裂构造复杂和非均质岩石的力学性质导致区域地应力变化复杂。研究基于高精度三维层位、断层地震解释数据构建了区域三维地质模型,通过单井测井解释–井间地震体数据联合建模方法确定了非均质致密油藏岩石力学参数展布,进一步应用构造应变系数法开展三维地应力场模拟,结果与井点实测地应力大小、方向吻合较好。模拟结果表明:Y176块沙四上亚层段现今地应力数值呈西南低、东北高的分布趋势;油藏断裂构造和非均质岩性对局部地应力场影响显著,断块内及不同断块之间的现今地应力场差异明显。针对非均质性致密油藏的三维地应力数值模拟研究为渤南油田致密储层高效勘探开发提供了准确的三维地应力场数据。

In-situ stress is the fundamental basis for efficient exploration and development of tight reser-voirs. Affected by regional fault structure and heterogeneous rock mechanical properties, the current stress field of tight oil reservoir in Y176 block of Bonan Oilfield varies complicatedly. In this research, 3D geological model is constructed based on high precision seismic interpretation data of 3D layers and faults. The heterogeneous rock mechanics parameters model of tight oil reservoir is established by well logging data and seismic volume data sampling. The three-dimensional stress field simulation is carried out by using the structure strain coefficient method, and the results are in good agreement with the measured in-situ stress magnitude and direction at the well site. The simulation results show that the in-situ stress is lower in southwest region and higher in northeast region for the Es4 layer of Y176 block. The effect of fault structure and heterogeneous lithology on local stress field is significant. The in-situ stress fields change obviously within and between fault blocks. The numerical simulation of three-dimensional geostress in heterogeneous tight oil reservoirs provides accurate basic data for efficient exploration and development of tight reservoirs in Bonan Oilfield.