考虑岩石蠕变的压裂水平井产能数值模拟及其影响因素

Numerical simulation for productivity of fractured horizontal well and its influencing factors considering rock creep 

刘绍成 张振南 赵兵 房好青

上海交通大学船舶海洋与建筑工程学院，上海 200240 中国石化西北油田分公司石油工程技术研究院，新疆 乌鲁木齐 830000

 在超深碳酸盐岩储层中，岩石处于高温高压环境下，表现出很强的蠕变特性。在油藏生产过程中，岩石蠕变对裂缝闭合有很大的影响，会影响到油藏演化和产能。针对这一问题，文中将裂缝蠕变闭合本构模型嵌入到单元劈裂法中，对水平井生产过程进行数值模拟研究，分析了储层参数和压裂方案对水平井产能的影响。结果表明：岩石蠕变将加速裂缝闭合，对水平井生产过程的影响显著。岩石弹性模量越高、岩石黏性系数越大以及应力差越小，水平井产能越高；U型布缝模式最有利于生产，水力裂缝长度越长，水平井产能越高。在设计水力裂缝数量的同时，需综合考虑水力裂缝间距及裂缝长度带来的影响才能达到有效增产目的。

Abstract: In ultra-deep carbonate reservoirs, rocks exhibit strong creep characteristics under high temperature and high pressure. In the process of reservoir production, rock creep has a great influence on fracture closure, which can affect reservoir evolution and productivity. In order to study this problem, the creep closure constitutive model of fracture is embedded into the element splitting method to simulate the production process of horizontal wells, and analyzes the impact of reservoir parameters and fracturing projects on the productivity of horizontal wells. The results show that rock creep will accelerate fracture closure and have a significant impact on the production process of horizontal wells. The higher the rock elasticity modulus, the greater the rock viscosity coefficient and the smaller the stress difference, the higher the productivity of horizontal well. U-shaped fractures mode is the most advantageous for production, and the longer the hydraulic fracture length, the higher the productivity of horizontal well. While designing the number of hydraulic fractures, it is necessary to comprehensively consider the influence of hydraulic fracture spacing and fracture length in order to effectively achieve the purpose of increasing production.

10.6056/dkyqt202304021