增强型地热系统水力压裂与声发射监测室内实验研究

增强型地热系统（enhanced geothermal system, EGS）以干热岩热能的开采和利用为目的,正逐渐成为世界各国的重点研究对象。除了建立EGS野外试验场开展实际场地研究和技术示范外,亦有必要开展相关的室内实验研究,研究或验证相关关键技术,为野外场地建设提供理论基础和技术支持。本课题组自主研发了模拟地下真实环境的实验系统,开展了尺寸为400 mm × 400 mm × 400 mm的花岗岩水力压裂实验,通过声发射事件监测到的声发射数据,分析了裂缝的扩展规律,并进行了初步的水力连通实验,探讨了各采出井的流量分配,研究了从注入井到生产井的水力连通特性。结果可为数值模拟提供基础数据,为野外试验场地的建设提供参考。

Laboratory Study on Hydraulic Fracturing and Acoustic Emission Monitoring of Enhanced Geothermal System

Aiming at extraction and utilization of hot dry rock thermal energy, enhanced geothermal system (EGS) is now a research focus across the world. Besides constructing field test site to carry out experimental studies and technical demonstration, it is also necessary to carry out lab tests to study or verify relevant key technologies. Laboratory tests can provide theoretical basis and technical support for the construction of field sites. Herein, a self-developed indoor experimental EGS was built to experimental system, which can simulate the underground pressure and temperature environment. With this experimental setup, the hydraulic fracturing experiment of a 400 mm × 400 mm × 400 mm granite block was carried out. Based on the monitored acoustic emission data, fracture growth and propagation in the rock block and perform preliminary hydraulic connection test were analyze. Flow distribution in the four surrounding production wells was evaluated, and the hydraulic connectivity from injection well to each production well was explored. The results obtained can provide basic data for numerical simulation and may have some reference value for the construction of real field test sites.