裂缝性非均质致密储层自适应应力敏感性研究

裂缝性致密储层具有非均质性强、应力敏感性强等特点，需明确储层非均质性及裂缝应力敏感性对生产的影响。为此，利用基于投影的嵌入式离散裂缝模型来表征复杂裂缝，结合应力敏感定量表征模型，建立了同时考虑基质和多尺度裂缝非均质性的应力敏感数值模型，自适应获得应力敏感特征曲线。模拟分析结果表明，强非均质致密储层不能忽略基质的应力敏感性，应力敏感性对生产早期的影响较大，以压裂裂缝的影响为主，随着生产逐渐过渡到基质，储层应力敏感性逐渐降低；早期生产压差过大，会造成储层应力伤害，不利于长期生产；不同充填程度的多尺度裂缝在储层中的分布模式对产能有直接影响，充填程度越低，裂缝尺度越大，产能越高。研究结果为致密裂缝性储层合理配产和开发方案优化提供了理论依据。 

Adaptive Stress Sensitivity Study of Fractured Heterogeneous Tight Reservoir

Fractured tight reservoirs are characterized by their strong heterogeneity and stress sensitivity. To understand with better clarity the influence of reservoir heterogeneity and fracture stress sensitivity on production, we employed the projection-based embedded discrete fracture model to characterize complex fractures. On this basis, a numerical stress sensitivity model considering matrix and multi-scale fracture heterogeneity was built by using the quantitative characterization model of stress sensitivity, and thus the stress sensitivity curve was obtained adaptively. The simulation results demonstrated that the stress sensitivity of the matrix could not be ignored in highly heterogeneous tight reservoirs because it had a great impact on production in the early stages, primarily with respect to hydraulic fractures. It was noted that the stress sensitivity of reservoirs decreased gradually as the production gradually transitioned from fractures to the matrix. Large differential production pressures in the early stages of production would cause a stress damage in the reservoir which was not conducive to long-term production. Moreover, the distribution pattern of multi-scale fractures with different filling degrees in reservoirs had a direct influence on productivity, as a less filled fracture in larger scale would provide higher productivity. The research results can provide a theoretical basis for rational production allocation and development scheme optimization of fractured tight reservoirs.