Groundwater Circulation And Heat Simulation Study In The Cretaceous Basin, The Ordos Basin

Abundant natural resources within the basin, such as coal, natural gas, petroleum and halite etc., make it likely to be the largest and world-rare basis of energy and heavy chemical plants. With the development of the mineral resources, groundwater demand will increase. Due to limited understanding of the groundwater circulation, groundwater development lacks solid basis. Cross-sectional simulation provides tools for addressing key issues of groundwater circulation and lays a solid basis for rational groundwater development. Based on the previous study, this paper carried out geothermal field simulation, aiming to verify Groundwater circulation patterns obtained from the previous study and provide parameters for hydrogeochemical simulation. .Partical tracking was used to indentify circulation rate at different depth. Modular structure model, Track2d, was developmed to update circulate rate at different depth. And isotopic modeling was updated using the updated porosity data. Based on the analysis of regional geothermal field, the geothermal model of the No. 2 cross section was developed. Simulation was done by the HST3D of USGS and model was calibrated to the observed data. Combined with study of hydraulic field and isotopic field, thermal field was used to study groundwater circulation.The results of the partical tracking study shows that groundwater circulates mostly in the shallow and intermediate groundwater systems(97% within 400m). The updated isotopic model produces the updated dispersivity values. The simulation shows that groundwater temperature protrudes downward in the Sishili Ridge, indicating cool water infiltration in the area. And in the Disitu River and Wusheng County, groundwater temperature protrudes upward, indicating groundwater with high temperatue moves upward. This indication has a good agreement with the existing conclusions. The simulation shows that in the Dusidu River, groundwater temperatue exceeds 30℃, which can be used to delineate zones with abundant geothermal resources.