国内外地热回灌发展现状及启示

Development status of geothermal reinjection at home and abroad and its enlightenment

曹倩 方朝合 李云 王汉雄 方群 史向阳

CAO Qian FANG Chaohe LI Yun WANG Hanxiong FANG Qun SHI Xiangyang

中国石油勘探开发研究院 中国石油华北油田公司

PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China PetroChina Huabei Oilfield Company, Renqiu 062552, Hebei, China

地热尾水回灌是维持地热资源可持续开采和预防地面沉降等地质环境问题的有效措施，对于各类正在开采的地热储层都具有重要意义，是决定地热能开发成败的关键因素。但地热回灌过程中可能引起生产井采出液温度降低、回灌井结垢和腐蚀、砂岩热储回灌井井筒和周围热储堵塞等问题，使得回灌效率降低，影响热储生产能力。为更好地解决地热尾水回灌问题，以国内外地热尾水回灌现状为出发点，调研了常见的回灌技术，分析了尾水回灌面临的主要问题和影响因素，并提出4点建议：(1)加强对地热储层研究，提高开发方式和热储的匹配度；(2)合理进行回灌设计，确保回灌系统的长时间平稳运行；(3)设置动态监测系统，作为后期开发的参考；(4)对回灌技术进行创新研发，提高尾水回灌量，实现经济上的最大化。这对降低地热尾水回灌难度，提高地热能的利用率，促进地热资源可持续开发具有重要意义。

Geothermal tail water reinjection is an effective measure to maintain the sustainable production of geothermal resources and prevent the problems of geological setting (e.g. surface subsidence), is of great significance to various geothermal reservoirs in production and is the key factor to the success of geothermal development. In the process of geothermal reinjection, however, some problems may be caused, such as temperature decline of the produced fluid in the production well, scaling and corrosion of reinjection well and blockage in the wellbore of reinjection well in sandstone geothermal reservoir and its surrounding geothermal reservoir, which decrease the reinjection efficiency and impact the geothermal reservoir productivity. In order to better solve the problems in the geothermal tail water reinjection, this paper firstly investigated the common reinjection technologies by taking the status of geothermal tail water injection at home and abroad as the beginning point. Then, the main problems and influence factors of tail water reinjection were analyzed and four suggestions were proposed as follows. First, strengthen the study on geothermal reservoirs to increase the matching degree between development mode and geothermal reservoir. Second, carry out reinjection design reasonably to ensure the smooth operation of the reinjection system in the long term. Third, set the dynamic monitoring system to provide the reference for the later development. Fourth, innovatively research and develop reinjection technologies to increase the volume of reinjected tail water and maximize the economic benefit. They are of important significance to decrease the difficulty of geothermal tail water reinjection, increase the utilization rate of geothermal energy and promote the sustainable development of geothermal resources.

10.13639/j.odpt.2021.02.011