鲁北馆陶组热储尾水回灌化学堵塞规律  

Chemical clogging pattern of hot reservoir tailwater recharge in the Guantao Formation,northern Shandong,China

作　　者：陶维昱 郑君 窦斌[1] 田红[1] 赖孝天 张晗 TAO Weiyu;ZHENG Jun;DOU Bin;TIAN Hong;LAI Xiaotian;ZHANG Han(Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074,China;Henan Geological Research Institute,Zhengzhou 450001,China)

机构地区：[1]中国地质大学(武汉)工程学院,武汉430074 [2]河南省地质研究院,郑州450001

出　　处：《地质科技通报》2025年第1期229-240,共12页Bulletin of Geological Science and Technology

基　　金：自然资源部深部地热资源重点实验室开放基金项目“基于小波频谱分析的干热岩粗糙裂隙渗流传热机理及热采性能研究”(KLDGR2022K01);岩土钻掘与防护教育部工程研究中心开放基金项目“粗糙面形貌特征对热储裂隙渗流传热影响机制研究”(202301);河南省重点研发专项(231111320800);中国地质大学(武汉)中央高校基本科研业务费资助项目(2024XLB79)。

摘　　要：地热尾水回灌是实现地热能绿色环保可持续利用的关键,但在地热尾水回灌过程中产生的堵塞问题已成为亟待攻克的难题,严重制约了砂岩热储的开发利用。为了更好地了解不同温度和时间对水化学的影响,以鲁北馆陶组砂岩热储为研究对象,利用高温高压渗流溶蚀实验平台,分别对岩样于25,45,65℃温度下开展了为期100 h的砂岩热储回灌实验,探究了回灌过程中尾水的离子浓度和pH值的演化规律,揭示了砂岩热储尾水回灌中化学堵塞过程和机理。研究结果表明,随着温度的升高,Na^(+)浓度逐渐上升,而Ca^(2+)和Mg^(2+)浓度稳步下降,且随着回灌时间的延长或温度的升高,Ca^(2+)和Mg^(2+)浓度的减少量逐渐增加。在65℃温度下,堵塞主要由Ca^(2+)和Mg^(2+)与重碳酸根和碳酸根发生反应所生成的沉淀造成,因此Ca^(2+)和Mg^(2+)的浓度与岩石样品的渗透率和化学堵塞率呈正相关。温度越高,化学堵塞程度越高,且快速增长阶段和快速下降阶段时间越久,化学反应越强烈,化学堵塞越严重。在实际工程中,可以利用降低回灌尾水的温度,或者通过在回灌前降低尾水的pH值,降低尾水中的Ca^(2+)、Mg^(2+)和HCO_(3)^(−)浓度来减轻化学堵塞的影响。[Objective]Geothermal brine reinjection is crucial for the sustainable and environmentally friendly utilization of geothermal energy.However,reinjection blockage presents a significant challenge,particularly hindering the development of sandstone reservoirs.This study explores the impact of temperature and reinjection duration on water chemistry,with a specific focus on the Guantao Formation sandstone reservoir in northern Shandong.[Methods]We employed a high-temperature and high-pressure core flow apparatus to conduct flowthrough dissolution tests on rock samples at temperatures of 25℃,45℃,and 65℃over a period of 100 hours.By analyzing changes in ion concentration and pH in the brine during reinjection,we aimed to uncover the mechanisms of chemical blockage in sandstone reservoirs.[Results]The results indicated that as the temperature rose,the concentration of Na+ion gradually increased,while the concentrations of Ca^(2+)and Mg^(2+)ions steadily declined.Prolonged reinjection time or elevated temperatures further reduced Ca^(2+)and Mg^(2+)concentrations.At 65℃,reactions involving Ca^(2+),Mg^(2+),bicarbonate,and carbonate ions led to precipitation,which significantly contributed to blockage.Thus,Ca^(2+)and Mg^(2+)concentrations were positively correlated with the permeability and chemical blockage rate of the rock samples.Longer reinjection durations and higher temperatures resulted in more severe chemical blockages.[Conclusion]In practical applications,reducing the pH of the brine before reinjection or lowering temperature could alleviate chemical blockage by decreasing Ca^(2+),Mg^(2+),and HCO3−concentrations.

关 键 词：尾水回灌 砂岩热储 离子浓度 化学堵塞 

分 类 号：P314.1[天文地球—固体地球物理学] X13[天文地球—地球物理学]