Numerical simulation is very useful in utilizing large scale geothermal energy,predicting reservoir response and optimizing exploitation procedure.Here we describe the OpenGeoSys(OGS)software used to simulate the complex processes in geoscience and hydrological applications,focusing on its application in geothermal energy utilization.OGS is based on an object-oriented finite element method concept and can deal with numerical simulation of thermo-hydro-mechanical-chemical processes in porous media.Case studies related to shallow geothermal energy(temperature and pressure prediction),hydrothermal energy(optimization on the distance between production well and reinjection well,scaling)and hot dry rock(hydraulic fracturing,permeability evolution)are shown with the purpose to help managing geothermal energy utilization.

Jiaodong is the biggest gold mineralization concentration area in China.The mineralization has direct relationship with Mesozoic granite.Most of deposits exist in regional shear zone where has the broken altered rock zone,which is the result of magmatic hydrothermal metasomatism.The main research problem of structure-fluid is how to guarantee the chosen rock sample can be used to do chemical fluid composition analysis and also used to observe tectonic deformation.We suggested that the potash feldspathized altered rock and the quartz-sericitized altered rock can be chosen as the research samples to solve this problem.This research method overcame the research difficulty in the regional structure-fluid area.The research result showed that the strain value decreases in potash feldspathized altered rock zone but increases in quartz-sericitized altered rock zone from west to east in the Jiaodong area;that the fluid homogenization temperatures increase in potash feldspathized altered rock zone but decrease in quartz-sericitized altered rock zone from west to east in the Jiaodong area.The chemical fluid composition has an obvious variation tendency.The Na+/K+variation tendency in quartz-sericitized altered rock zone shows that the west of Jiaodong has more K+than east and K+is beneficial for mineralization;that the east of Jiaodong has more Na+than west and Na+is beneficial for fluid migration.The contents of CH4 and CO2 decrease from west to east,which is positively correlated with the enrichment of Au element.The characteristics of structure-fluid in fractured altered rock zone revealed the trend that the metallogenic hydrothermal fluid migrated from west to east in the Jiaodong region.This trend had its impact on the gold deposit scale,type and distribution.