Surface characteristics analysis of fractures induced by supercritical CO_(2)and water through three-dimensional scanning and scanning electron micrography  

作　　者：Hao Chen Yi Hu Jiawei Liu Feng Liu Zheng Liu Yong Kang Xiaochuan Wang 

机构地区：[1]Hubei Key Laboratory of Waterjet Theory and New Technology,Wuhan University,Wuhan,430072,China [2]School of Power and Mechanical Engineering,Wuhan University,Wuhan,430072,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2021年第5期1047-1058,共12页岩石力学与岩土工程学报（英文版）

基　　金：National Natural Science Foundation of China(Grant No.51804318);the China Postdoctoral Science Foundation Founded Project(Grant No.2019M650963);National Key Basic Research and Development Program of China(Grant No.2014CB239203).

摘　　要：Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance.

关 键 词：Supercritical carbon dioxide(SC-CO_(2))fracturing Quantitative characterization of surface features Surface roughness and fractal dimension Three-dimensional(3D)scanning Scanning electron micrograph(SEM) 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程] TE377[自动化与计算机技术—计算机应用技术] TP391.41[自动化与计算机技术—计算机科学与技术]