深地能源工程热水力多场耦合效应高效模拟方法

A ROBUST NUMERICAL MODELING FRAMEWORK FOR COUPLED THERMO-HYDRO-MECHANICAL PROCESS IN DEEP GEO-ENERGY ENGINEERING

深地能源工程多场耦合效应数值模拟面临的主要难题有深部岩体的非线性力学特性、复杂的赋存环境、以及围岩-结构尺寸相差悬殊的计算瓶颈。针对深地能源工程井筒结构独特的细长型几何特点,将井筒简化为一维线单元,考虑井筒内流体沿井筒轴向的渗流传热,而井筒内流体与周围岩体的换热过程则采用等效换热系数近似考虑,套管和砂浆层的影响包含在等效换热系数中,利用该方法实现了远场尺度深地能源工程热-水-力多场耦合效应的高效模拟。依托中国京津冀及周边地区典型水热型地热田群井系统开展案例研究,不仅证明了该文所提出的数值模拟方法可兼顾百平方千米尺度深地能源工程多场耦合效应模拟分析的精度与效率,还揭示了深部热储温度场、渗流场、变形场的长期演化特征。

The performance and safety assessment of the coupled thermo-hydro-mechanical process in deep geo-energy engineering are challenging,because of the complex mechanical behavior of deep reservoir rocks and in-situ geological conditions,as well as the scale disparity between wells and reservoirs.To improve the computational efficiency without losing accuracy,a simplified one-dimensional well model considering heat convection and conduction along well axis and heat transfer between fluid and cap rocks in the radial direction is proposed and incorporated into the deep reservoir model.Two case studies of the city geothermal fields in Beijing and Shandong,China,are presented to demonstrate the reasonability and efficiency of the proposed reservoir modeling method.The evolutions of the temperature,flow velocity and deformation fields in deep reservoirs are also discussed.