Gas channeling control with an in-situ smart surfactant gel during water-alternating-CO_(2) enhanced oil recovery  

作　　者：Xin-Jie Luo Bing Wei Ke Gao Bo Jing Bo Huang Ping Guo Hong-Yao Yin Yu-Jun Feng Xi Zhang 

机构地区：[1]Polymer Research Institute,State Key Laboratory of Polymer Materials Engineering,Sichuan University,Chengdu 610065,Sichuan,China [2]National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,Sichuan,China [3]National Key Laboratory of Offshore Oil Exploitation,CNOOC Research Institute Ltd.,Beijing 102209,China

出　　处：《Petroleum Science》2023年第5期2835-2851,共17页石油科学（英文版）

基　　金：Financial support from the Natural Science Foundation of Sichuan Province(2022NSFSC0030);National Natural Science Foundation of China(U1762218)is gratefully acknowledged.

摘　　要：Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling”paths usually suffer from either low injectivity or poor gelation control.Herein,we for the first time developed an in-situ high-pressure CO_(2)-triggered gel system based on a smart surfactant,N-erucamidopropyl-N,N-dimethylamine(UC22AMPM),which was introduced into the aqueous slugs to control gas channeling inWAG processes.The water-like,low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO_(2) owing to the formation of wormlike micelles(WLMs),as well as their growth and shear-induced structure buildup under shear flow.The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating,and can be impaired via pressurization above the critical pressure of CO_(2) because of its soaring solvent power.Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre-or post-injected CO_(2) slugs under shear flow,thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode.This smart surfactant enabled high injectivity and satisfactory gelation control,attributable to low initial viscosity and the combined properties of one component and CO_(2)-triggered gelation,respectively.This work could provide a guide towards designing gels for reducing CO_(2) spillover and reinforcing the CO_(2) sequestration effect during CO_(2) enhanced oil recovery processes.

关 键 词：CO_(2)flooding Enhanced oil recovery Gas channeling Water-alternating-CO_(2) Smart surfactant GEL 

分 类 号：TE357.46[石油与天然气工程—油气田开发工程]