Numerical simulation of fracturing and imbibition in shale oil horizontal wells

作     者：Rong-Li Xu Tian-Kui Guo Xiao-Jia Xue Wen-Bin Chen Zhan-Qing Qu Ming Chen Zun-Peng Hu 

作者机构：National Key Laboratory of Deep Oil and GasChina University of Petroleum(East China)Qingdao266580ShandongPR China School of Petroleum EngineeringChina University of Petroleum(East China)Qingdao266580ShandongPR China Oil and Gas Technology Research Institute Changqing Oilfield CompanyPetrochina Company LimitedXi'an710000ShaanxiPR China 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2023年第20卷第5期

页      面：2981-3001页

核心收录：

学科分类：0820[工学-石油与天然气工程] 08[工学] 082002[工学-油气田开发工程] 

基　　金：the financial support of the National Key Research and Development Program of China(2020YFA0711804) the National Natural Science Foundation of China(Grant No.52074332) express their gratitude to project ZR2020YQ36 supported by Shandong Provincial Natural Science Foundation 

主　　题：Shale oil Hydraulic fracturing Imbibition exchange volume Oilewater two-phase flow Shut-in time 

摘      要：The shale oil reservoir is characterized by tight lithology and ultra-low permeability,and its efficient exploitation requires the technology of multi-stage and multi-cluster hydraulic fracturing in horizontal wells and shut-in *** multi-stage and multi-cluster hydraulic fracturing,a complex fracture network is formed,and a large volume of frac fluid is stored within the fracture *** shut-in,imbibition and exchange between oil and water occurs under the action of the capillary force and osmotic pressure,and the formation pressure builds up in the shale *** basis of the characteristics of shale oil reservoir,we establish a model of imbibition during fracturing injection and shut-in by coupling oilewater two-phase flow and saline ion diffusion in the hydraulic fractures(HFs)network,natural fractures(NFs)and matrix system under the action of capillary force and osmotic *** DFN method and the multiple continuum method are introduced to characterize fluid flow between the HF and the NF and that between the NF and the matrix respectively,which avoids the problem of a large amount of computation of seepage within the complex ***,the discrete fracture network(DFN)model and the multiple continuum model are solved with the finite element method,and it is verified in flow field,saturation field and concentration field that the models are accurate and *** propose the imbibition exchange volume for quantitative evaluation of the imbibition degree and a method of calculating the imbibition exchange *** of oil and water flow in the fracturing and shut-in stages is performed based on these *** is found that imbibition in the shale reservoir is driven by mechanisms of pressure difference,capillary force and osmotic *** osmotic pressure and capillary force only cause an increase in the imbibition rate and a reduction in the imbibition equilibrium time and do not lead to variation in the peak of i