摘要
为陆相页岩压裂返排液污染含水层的精准识别,依托柴北缘第1口陆相页岩气勘探井——柴页1井,对比分析页岩气开发区背景地下水、压裂返排液和常规油田卤水(COB)的水化学和同位素特征,探讨压裂返排液污染含水层的标识。研究结果表明:①柴北缘地区极度干旱的气候条件、含水层矿物组成以及陆相页岩的沉积环境,导致海相页岩气田常用的返排液识别指标,如Cl-、溶解性总固体、水化学类型、主要离子比值和氢氧同位素等均不适用于该区陆相页岩返排液的识别标识;②柴北缘地区常规和非常规油气的共同开采现状,使C1/C1-5、δ13C-CH4等页岩气化学和同位素指标不适用于页岩压裂返排液的溯源标识;③返排液中δ11B和87Sr/86Sr的分布范围与浅层地下水和COB均不重叠,有较大的可区分空间,是返排液污染浅层地下水的潜在识别指标。研究成果可为中国北方页岩气开发的环境影响评价及相关环境立法提供指导建议,促进中国北方页岩气勘查开发工作的环境友好进行。
In order to identify the groundwater pollution by hydraulic fracturing flowback fluids(HFFF)produced from continental shale gas reservoir,the hydrochemical and isotopic characteristics of background groundwater,HFFF,and conventional oilfield brine(COB)in the Dameigou shale gas reservoir were analyzed based on the first continental shale gas exploration well(Chaiye 1 Well)in northwest China.The results show as follows.Common indicators for HFFF of marine shale such as Cl-,total dissolved solids,hydrochemistry type,main ion ratios,and hydrogen/oxygen isotope are not applicable to the HFFF of continental shale in groundwater due to the extreme drought climate conditions,aquifer mineral compositions,and depositional environment of continental shale in the northern Qaidam Basin.Shale gas chemical and isotopic indexes such as C1/C1-5 andδ13C-CH4 are not applicable to the traceable marks of HFFF in groundwater due to the joint exploitation of conventional and unconventional oil/gas in the northern Qaidam Basin.The range ofδ11B and 87Sr/86Sr in the flowback fluids is significantly different from that of shallow groundwater and COB.Therefore,theδ11B and 87Sr/86Sr are the potential indicators of HFFF for shallow groundwater pollution in study area.These results can provide a scientific basis for assessment of groundwater pollution and legislation of related environment in the continental shale gas reservoirs in the northern China,also can promote the exploration and development of shale gas in the northern China in an environmentally friendly manner.
作者
郑昭贤
崔小顺
朱谱成
陈宗宇
ZHENG Zhao-xian;CUI Xiao-shun;ZHU Pu-cheng;CHEN Zong-yu(Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Science, Shijiazhuang 050061, China;Key Laboratory of Groundwater Sciences and Engineering, Ministry of Natural Resources, Zhengding 050803, China)
出处
《科学技术与工程》
北大核心
2021年第14期5710-5718,共9页
Science Technology and Engineering
基金
国家自然科学基金(41302192)
河北省自然科学基金(D2018504011)
自然资源部公益性行业科研专项(201411052)
中国地质科学院基本科研业务费项目(SK202005)。
关键词
页岩气
压裂返排液
地下水污染
污染识别
水化学
同位素
shale gas
fracturing flowback fluids
groundwater contamination
contamination identification
hydrochemistry
isotope
