Chronological Study of Coal-seam Water and its Implication on Gas Production in the South Qinshui Basin

作     者：CHEN Biying FANG Lujia LANG Yunchao XU Sheng LIU Congqiang ZHANG Luyuan HOU Xiaolin CHEN Biying;FANG Lujia;LANG Yunchao;XU Sheng;LIU Congqiang;ZHANG Luyuan;HOU Xiaolin

作者机构：Institute of Surface-Earth System ScienceSchool of Earth System ScienceTianjin UniversityTianjin 300072China Institute of Earth EnvironmentsChinese Academy of SciencesXi’an 710061China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2024年第98卷第1期

页      面：207-219页

核心收录：

学科分类：0202[经济学-应用经济学] 02[经济学] 020205[经济学-产业经济学] 0708[理学-地球物理学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.42150710532 and 42103048) 

主　　题：CBM co-produced water iodine-129 chlorine-36 water chemistry Qinshui Basin 

摘      要：The knowledge of the residence time of formation water is fundamental to understanding the subsurface flow and hydrological *** better identify the origin and evolution of coal seam water and its impact on gas storage and production,this study collected coalbed methane co-produced water in the southeast Qinshui Basin and detected chemical and isotopic compositions,especially 36Cl and 129I *** calculated tracer ages of 129I(5.2–50.6 Ma)and 36Cl(0.13–0.76 Ma)are significantly younger than the age of coal-bearing formation(Pennsylvanian-Cisuralian),indicating freshwater recharge after coal *** model that utilises 129I/I and 36Cl/Cl ratios to constrain the timing of recharge and the proportion of recharge water reveals that over 60%of pre-anthropogenic meteoric water entered coal seams since 10 Ma and mixed with residue initial deposition water,corresponding to the basin inversion in *** spatial distribution of major ion concentrations reveals the primary recharge pathway for meteoric water from coal outcrops at the eastern margin to the basin *** study demonstrates the occurrence of higher gas production rates from wells that accept water recharge in recent times and suggests the possible potential of the non-stagnant zones for high gas production.