Research progress on isotopic fractionation in the process of shale gas/coalbed methane migration  

作　　者：LI Wenbiao LU Shuangfang LI Junqian WEI Yongbo ZHAO Shengxian ZHANG Pengfei WANG Ziyi LI Xiao WANG Jun 

机构地区：[1]Sanya Offshore Oil&Gas Research Institute,Northeast Petroleum University,Sanya 572025,China [2]Key Laboratory of Continental Shale Hydrocarbon Accumulation and Efficient Development,Ministry of Education,Northeast Petroleum University,Daqing 163318,China [3]School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China [4]Exploration and Development Research Institute of Daqing Oilfield Co.Ltd.,Daqing 163712,China [5]Shale Gas Research Institute of PetroChina Southwest Oil&Gasfield Company,Chengdu 610051,China [6]College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China

出　　处：《Petroleum Exploration and Development》2022年第5期1069-1084,共16页石油勘探与开发（英文版）

基　　金：National Postdoctoral Innovative Talent Support Program(BX20220062);National Natural Science Foundation of China(41672130 and 41972123);SINOPEC Corp.(P17027-3)。

摘　　要：The research progress of isotopic fractionation in the process of shale gas/coalbed methane migration has been reviewed from three aspects: characteristics and influencing factors, mechanism and quantitative characterization model, and geological application. It is found that the isotopic fractionation during the complete production of shale gas/coalbed methane shows a four-stage characteristic of “stable-lighter-heavier-lighter again”, which is related to the complex gas migration modes in the pores of shale/coal. The gas migration mechanisms in shale/coal include seepage, diffusion, and adsorption/desorption. Among them, seepage driven by pressure difference does not induce isotopic fractionation, while diffusion and adsorption/desorption lead to significant isotope fractionation. The existing characterization models of isotopic fractionation include diffusion fractionation model, diffusion-adsorption/desorption coupled model, and multi-scale and multi-mechanism coupled model. Results of model calculations show that the isotopic fractionation during natural gas migration is mainly controlled by pore structure, adsorption capacity, and initial/boundary conditions of the reservoir rock. So far, the isotope fractionation model has been successfully used to evaluate critical parameters, such as gas-in-place content and ratio of adsorbed/free gas in shale/coal etc. Furthermore, it has shown promising application potential in production status identification and decline trend prediction of gas well. Future research should focus on:(1) the co-evolution of carbon and hydrogen isotopes of different components during natural gas migration,(2) the characterization of isotopic fractionation during the whole process of gas generation-expulsion-migration-accumulation-dispersion, and(3) quantitative characterization of isotopic fractionation during natural gas migration in complex pore-fracture systems and its application.

关 键 词：shale gas coalbed methane diffusive fractionation adsorption/desorption fractionation isotope fractionation model natural gas migration 

分 类 号：TE37[石油与天然气工程—油气田开发工程]