A study on modeling a deep sand geothermal field in South China

Abstract

It is crucial for financial providers, investment groups, resource developers and exploration companies to rate a new geothermal project in the respect of resource and reserve. The existing volumetric method is generally constrained by limited information when projects at the early stage of development. The objective of this study is to estimate the potential of a geothermal field by a refined geological model and 3D numerical temperature model. We establish a fine geological model of a geothermal field in South China and thereby calculate the conductive 3D numerical temperature model. Based on a comprehensive analysis and interpretation of borehole measured data and well-log data, the regional variation and spatial distribution of thermal and petrophysical properties are both incorporated in the geological model. The results show that the Neogene and Quaternary strata in the study area have an average porosity of 36% and an average rock thermal conductivity of 3.15 W (m K)−1, the Weizhou Formation have an average porosity of 29% and an average rock thermal conductivity of 2.54 W (m K)−1, the Liushagang Formation have an average porosity of 22 % and an average thermal conductivity of 2.21 W (m K)−1, the Changliu Formation have an average porosity of 13% and an average thermal conductivity of 2.75 W (m K)−1. Based on the fine geothermal geological model, the heat is assumed to be driven by conduction, and the results show that the bottom temperature of the Weizhou Formation in the hydrothermal sandstone reservoir is 96-168 degrees Celsius, and the high temperature area is concentrated near the down-thrown side of the fault, indicating that the geothermal resources are favorable area and the geothermal energy is 7.89 × 1014 J.