砂岩热储回灌难点识别与应对措施探讨  

Insights into the root causes of difficulties in reinjection in sandstone geothermal reservoir and countermeasures

作　　者：赵侃[1,2] 沈健 蔡芸[1,2] 赵苏民 ZHAO Kan;SHEN Jian;CAI Yun;ZHAO Sumin(Tianjin Institute of Geothermal Exploration and Development-Design,Tianjin 300250,China;Observation and Research Station of Tianjin Low-Medium Temperature Geothermal Resources,Ministry of Natural Resources,Tianjin 300250,China)

机构地区：[1]天津地热勘查开发设计院,天津300250 [2]自然资源部天津中低温地热野外科学观测研究站,天津300250

出　　处：《地学前缘》2024年第6期196-203,共8页Earth Science Frontiers

基　　金：国家重点研发计划项目(2019YFB1504204)。

摘　　要：砂岩热储在我国分布面积广,热储厚度大,资源储量丰富,是我国北方和西部地区地热供暖的主力热储。但砂岩热储回灌量偏小,回灌过程易衰减,难以规模化开发,这些都是现实存在的难题。已有研究成果主要集中在钻井液污染、物理堵塞和化学堵塞方面,这些都是造成砂岩热储回灌困难的常见原因。本文在充分研究油田注水技术、收集砂岩岩心实验测试和野外回灌试验资料的基础上,分析总结了天津、山东、陕西等地砂岩热储生产性回灌实际案例,认为砂岩热储孔隙直径小、孔隙喉道迂曲度大和回灌流体渗流沿程摩阻力(压耗)大是造成回灌量偏小和衰减的根本原因。主要应对措施是精确识别砂岩热储特征,扩大回灌井井径,改造热储以减小近井地带的回灌流速,抑制以速敏为主的水岩作用发生,这是今后解决砂岩热储回灌困难的关键。Abundant sandstone geothermal reservoirs with large reservoir thickness are widely distributed in China,and they are the main geothermal resource for heating in the country’s northern and western regions.However,sandstone reserviors are difficult to recharge due to the small rechargeable volume,high recharge decay,and difficulty to develop on a large scale.Previous researches mainly focused on the common causes,such as drilling fluid contamination and physical/chemical clogging.Based on comprehensive review of oilfield water injection technology and results from sandstone core experiments and field reinjection tests,combined with analysis and summary of production reinjection data as well as results from sandstone reservoirs in Tianjin,Shandong and Shaanxi,we considered that the root causes of small recharge volume and recharge decay were small pore diameter,highly tortuous pore channel,and high frictional resistance(pressure dissipation)along the seepage channel of reinjection fluids.The countermeasures identified included accurate characterization of sandstone reservoirs,enlargement of reinjection wells,reduction of reinjection flow rate in the near-well area,and inhibition of speed-sensitive hydrological interactions.

关 键 词：砂岩热储 回灌 堵塞 馆陶组 渗流通道 压力梯度 

分 类 号：P314[天文地球—固体地球物理学] P641[天文地球—地球物理学]