水平井“多段分簇”压裂簇间干扰的数值模拟

A numerical simulation of the inter-cluster interference in multi-cluster staged fracking for horizontal wells

水平井"多段分簇"压裂是开发低渗透和非常规油气藏的关键技术,能够大幅度提升压裂改造的体积,达到提高油气产量和最终采收率的目的。为了研究水平井"多段分簇"压裂簇间裂缝的干扰规律,基于多孔介质流—固耦合的基本方程,根据损伤力学基本理论,利用零厚度黏结单元模拟压裂过程中压裂裂缝起裂、延伸造成的损伤,建立了低渗透油气藏水平井"多段分簇"压裂裂缝扩展的三维有限元模型。利用该模型研究了射孔簇数、射孔簇间距、储层参数、施工参数等对水平井"多段分簇"压裂簇间裂缝干扰的影响。模拟计算结果表明:射孔簇数和射孔簇间距是影响水平井"多段分簇"压裂簇间裂缝干扰的最大的影响因素。利用该模型对某水平井压裂的射孔簇间距进行了优化,使得该井的油气产量比邻井明显提高,证明了模型对于水平井"多段分簇"压裂优化的可行性和可靠性。

Multi-cluster staged fracking is a key technology to develop low permeability and unconventional reservoirs, with which, the stimulated reservoir volume （SRV） can be increased significantly, so as to enhance the oil or gas production and ultimate recover- y. In order to study the interference between fractures of different clusters in multi-staged fractured horizontal wells, a three-dimen- sion finite element model for simulating the propagation of fractures was established. The model was theoretically based on fluid-solid coupling equations in porous medium and damage mechanics, and zero thickness cohesive element was adopted to simulate the rock damage during the initiation and propagation of artificial fractures. Factors affecting the inter-cluster fracture interference in multi cluster staged fraeking, including perforation cluster numbers, cluster spacing, reservoir and treatment parameters, were researched by a series of simulations. The results showed that the perforation cluster numbers and spacing are two primary factors. Based on the model, the cluster spacing of a horizontal wei1 was optimized. As a result, the production of this well was distinctively improved compared with that of the adjacent well, which proves that the model is feasible and reliable in optimizing the design of multi-cluster staged fracking for horizontal wells.