含层理储层水力压裂缝高延伸规律及现场监测

层理作为页岩油气储层的重要特征，对水力裂缝垂向扩展存在显著影响。通过开展理论分析，创新大尺度水力压裂模拟实验方法，以及针对现场尺度页岩油气储层实施水力裂缝形态监测，揭示层理条件下裂缝垂向扩展形态，明确裂缝穿层主控因素，为非常规储层改造工艺优化提供指导。研究表明：与层理面相交时，水力裂缝存在穿过、止裂（层理剪切或张开）和偏移3种扩展结果；实验及现场监测均证实了层理面胶结强度是影响缝高延伸的最重要因素，根据胶结强度不同既存在水平层理对缝高的抑制，也存在缝高穿过层理的情形；此外平面上天然裂缝展布形态和垂向储隔层间物性差异也对缝高延伸有明显影响。研究认识可为非常规层理条件下水力裂缝穿层工艺优化设计提供技术支撑。

The study of hydraulic fracture vertical propagation in unconventional reservoir with beddings and field monitoring

As an important characteristic of shale oil and gas reservoir, bedding has a significant influence on vertical propagation of hydraulic fractures. Through theoretical analysis, innovation of large-scale hydraulic fracturing simulation experiment method, and field scale hydraulic fracture monitoring for shale oil and gas reservoirs, the vertical fracture propagation patterns under bedding condition are revealed, and the main controlling factors of fracture penetration are identified, which could guide the optimization of unconventional reservoir treatment. The experiments indicate that there are three different kinds of results when the fracture height reaches the bedding plane: crossing directly, crossing offsets and arresting (bedding slippage or dilation). Besides, the orthogonal analysis shows that the bedding strength is one of the most critical influences on fracture height. The field practice further confirms that weak bedding plane can arrest fracture height obviously and the fracture height also can cross the bedding because of strong bedding interface. In addition, the natural fractures on the plane and the difference of mechanical properties between layers also have significant influence on the fracture height. The research can provide technical support for the optimization design of hydraulic fracture vertical propagation under the bedding existence in unconventional reservoir.