低渗气井压裂液返排模型研究  

Research on Fracturing Fluid Flowback Model for Low-Permeability Gas Wells

作　　者：陈守雨 杜林麟 

机构地区：[1]东方宝麟科技发展(北京)有限公司,北京100083

出　　处：《中外能源》2016年第2期30-35,共6页Sino-Global Energy

摘　　要：低渗气井压裂液返排动态研究对合理制定返排制度、优化压后产能有着实际意义。压后返排是影响产能的重要因素之一。从低渗气井压裂液返排所涉及到的流动出发,建立包括气藏渗流、侵入区滤失压裂液渗流、压裂液裂缝内返排流动和井筒气液两相流动等4个过程的压裂液返排数值模型,考虑储层物性、滤失区物性、裂缝特征及井筒在返排过程中对流动动态特征的影响,并系统研究返排数值模型耦合求解计算方法,实现低渗气井压裂液返排过程的动态模拟。利用返排数值模型对实际井例进行计算,研究缝长、裂缝导流能力、储层渗透率及流度、液氮助排等因素对压裂液返排动态特征、返排效果和产能的影响程度。研究表明,滤液侵入区相渗变化导致永久性产能损失不会发生,而裂缝内紊流将损耗裂缝有效长度,降低气相有效渗透率,制约气井产能,返排控制时应当予以重视。Research on dynamics of fracturing fluid flowback in low-permeability gas wells is significant for rational flowhack scheme and post-fracture productivity optimization since post-fracture flowback is one of the important factors impacting gas well productivity.Based on all flow behaviors in the process of fracturing fluid flowback in the low-permeability gas wells,and numerical models including gas reservoir flow,fracturing fluid leakoff flow in invaded zone,flowback of fracturing fluid in fracture space and liquid-gas two phase flow in wellbore were established with the consideration of the impacts of physical properties of reservoirs,physical property of leakoff zone ,fracture characterisitics as well as wellbore dynamic flow parameters during the pro- cess of flowback.A coupled numerical algorithm was also developed systematically to solve the numerical model of flowback so that dynamic modeling of fracturing fluid flowback in the low-permeability gas wells has been realized.The model was applied for actual well cases.The effects of fracture length,fracture conduc- tivity ,reservoir permeability and mobility,liquid nitrogen eleaup on the flowback dynamics,result and produc- tivity were investigated.The results show that the occurrence of permanent productivity damage caused by rel- ative permeability profile variation in the invaded zone is unlikely,but turbulence flow in the fracture may harm effective fracture length and lower effective permeability of gas phase so that production performance of the gas wells may be constrained,which should be concerned during flowback control.

关 键 词：低渗气井 压裂液返排 模型 耦合计算方法 影响因素 

分 类 号：TE377[石油与天然气工程—油气田开发工程]