Development simulation in Gucheng County, Hebei Province: Comparative study of the thermal storage development of clastic and carbonate rocks

There are two sets of thermal reservoirs with different rock types in the Gucheng geothermal field of Hebei Province, namely the Ordovician fractured carbonate thermal reservoir and the Neogene Guantao sandstone thermal reservoir, each developed using independent well networks. The energy demand per unit area in the region is high, and the existing geothermal development methods cannot meet the regional energy demand. For this type of block, combined with the development characteristics of different types of thermal reservoirs, numerical simulation methods were used to study the geothermal development trends of Ordovician fractured carbonate reservoirs and Neogene Guantao Formation sandstone reservoirs. When simulating sandstone thermal storage, priority should be given to demonstrating the optimal recharge flow rate, while in simulating carbonate thermal storage, the focus should be on considering the influence of fracture development direction on development trends. Through numerical simulation of thermal storage development and combined with well network design, the optimal well spacing, production reinjection flow rate, and reinjection temperature for two sets of thermal reservoirs developed using the same well network were determined. It is predicted that the average heat flow in the study can increase by 47.8 %. This study presents reasonable development technical countermeasures to maximize the heating capacity of the geothermal development zone and provides an effective reference for the efficient development of similar geothermal resources in the Bohai Bay Basin.