The effects of various factors on spontaneous imbibition in tight oil reservoirs

作     者：Cheng Liu Tian-Ru Wang Qing You Yue-Chun Du Guang Zhao Cai-Li Dai Cheng Liu;Tian-Ru Wang;Qing You;Yue-Chun Du;Guang Zhao;Cai-Li Dai

作者机构：School of Energy ResourcesChina University of GeosciencesBeijing100083PR China School of Petroleum EngineeringChina University of PetroleumQingdao266580ShandongPR China 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2024年第21卷第1期

页      面：315-326页

核心收录：

学科分类：0820[工学-石油与天然气工程] 081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070302[理学-分析化学] 0703[理学-化学] 082002[工学-油气田开发工程] 

基　　金：The authors sincerely appreciate the financial support from the National Natural Science Foundation of China(No.52074279 51874261) 

主　　题：Tight oil reservoir Spontaneous imbibition Nuclear magnetic resonance Slickwater fracturing fluid Fluid utilization degree 

摘      要：Slickwater fracturing fluids have gained widespread application in the development of tight oil reservoirs. After the fracturing process, the active components present in slickwater can directly induce spontaneous imbibition within the reservoir. Several variables influence the eventual recovery rate within this procedure, including slickwater composition, formation temperature, degree of reservoir fracture development, and the reservoir characteristics. Nonetheless, the underlying mechanisms governing these influences remain relatively understudied. In this investigation, using the Chang-7 block of the Changqing Oilfield as the study site, we employ EM-30 slickwater fracturing fluid to explore the effects of the drag-reducing agent concentration, imbibition temperature, core permeability, and core fracture development on spontaneous imbibition. An elevated drag-reducing agent concentration is observed to diminish the degree of medium and small pore utilization. Furthermore, higher temperatures and an augmented permeability enhance the fluid flow properties, thereby contributing to an increased utilization rate across all pore sizes. Reduced fracture development results in a lower fluid utilization across diverse pore types. This study deepens our understanding of the pivotal factors affecting spontaneous imbibition in tight reservoirs following fracturing. The findings act as theoretical, technical, and scientific foundations for optimizing fracturing strategies in tight oil reservoir transformations.