水平井多段分簇压裂裂缝扩展形态数值模拟  

Numerical simulation study on fracture extension and morphology of multi-cluster staged fracturing for horizontal wells

作　　者：曲占庆 田雨 李建雄 郭天魁 李小龙 刘晓强 

机构地区：[1]中国石油大学石油工程学院,山东青岛266580

出　　处：《中国石油大学学报（自然科学版）》2017年第1期102-109,共8页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学青年基金项目(51404288);中央高校基本科研业务费专项(15CX06029);中国石油大学(华东)科研启动基金项目(Y1302055);中国石油大学(华东)研究生创新工程项目(YCXJ2016024)

摘　　要：水平井多段分簇压裂技术已成为低渗透油气增产的关键技术,能够大幅度增加储层的泄油面积,最大限度地提高采收率,而射孔簇间的应力干扰是影响水平井多段分簇压裂的关键因素。为了提高储层改造体积,研究簇间裂缝扩展的规律,根据流-固耦合及岩石断裂力学理论,利用ABAQUS扩展有限元法建立水平井多段分簇水力压裂二维模型,并利用数值模拟结果对现场2口井的压裂参数进行优化。数值模拟结果表明:水力裂缝长度、簇间距、水平应力差、压裂次序对水力裂缝形态影响显著;裂缝诱导应力场对裂缝形态影响程度随裂缝长度增加逐渐增强,随簇间距和水平应力差的增大逐渐降低;水力压裂次序可以明显改变诱导应力场分布,合理利用能增加有效裂缝长度。现场压裂参数优化后的2口井产能得到明显提高,证明了数值模型的可行性。Multi-cluster staged fracturing of horizontal wells is a key technology to enhance oil recovery of low permeability reservoirs,by which the oil drainage area can be increased obviously to improve ultimate oil recovery.In the fracturing process,the stress interference among different clusters can affect the propagation of the fractures and is the key factor affecting the process.In order to increase the stimulated reservoir volume and study the extension of fractures between clusters,a two-dimension simulation model was established,in which an ABAQUS extended finite element method was used based on fluid-solid coupling equations and rock fracture mechanics.The method was applied in two horizontal wells for fracturing optimization,and their results were compared with the adjacent wells with no optimization.The results show that the fracture length,the distance between clusters and the difference of principal stresses can have a great influence on the fracture morphology.As the fracture length increases,the influence of the induced stress field on fracture morphology can be gradually strengthen.The cluster space and the rise of the horizontal stress difference rise can weaken the induced stress field.The sequence of the cluster fracturing can change the distribution of the induced stress field evidently.The fracture length can be extended further via optimizing the fracturing sequence.The two optimized wells had higher yield than the adjacent wells,which prove the effectiveness and feasibility of the model for field application.

关 键 词：水平井 多段分簇压裂 岩石断裂力学 流-固耦合 扩展有限元方法 缝间干扰 裂缝形态 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]