Characteristics and mechanisms of supercritical CO_(2) flooding under different factors in low-permeability reservoirs  

作　　者：Zheng Chen Yu-Liang Su Lei Li Fan-Kun Meng Xiao-Mei Zhou 

机构地区：[1]School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,266580,Shandong,PR China [2]Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)),Ministry of Education,Qingdao,266580,Shandong,PR China [3]School of Petroleum Engineering,Yangtze University,Wuhan,430100,Hubei,PR China

出　　处：《Petroleum Science》2022年第3期1174-1184,共11页石油科学（英文版）

基　　金：financial support from the National Natural Science Foundation of China(No.51904324,51974348,U19B6003)

摘　　要：In recent years,supercritical CO_(2)flooding has become an effective method for developing lowpermeability reservoirs.In supercritical CO_(2)flooding different factors influence the mechanism of its displacement process for oil recovery.Asynchronous injection-production modes can use supercritical CO_(2)to enhance oil recovery but may also worsen the injection capacity.Cores with high permeability have higher oil recovery rates and better injection capacity,however,gas channeling occurs.Supercritical CO_(2)flooding has a higher oil recovery at high pressure levels,which delays the occurrence of gas channeling.Conversely,gas injection has lower displacement efficiency but better injection capacity at the high water cut stage.This study analyzes the displacement characteristics of supercritical CO_(2)flooding with a series of experiments under different injection and production parameters.Experimental results show that the gas breakthrough stage has the fastest oil production and the supercritical CO_(2)injection capacity variation tendency is closely related to the gas-oil ratio.Further experiments show that higher injection rates represent significant ultimate oil recovery and injection index,providing a good reference for developing low-permeability reservoirs.

关 键 词：Low-permeability reservoir Supercritical CO_(2)flooding Influence mechanism Enhanced oil recovery Injection capacity 

分 类 号：TE348[石油与天然气工程—油气田开发工程]