Hydrothermal Features of The Neogene Guantao Sandstone Porous Geothermal Reservoir In The North China Basin

Utilization of low-temperature (<150°C) geothermal water, particularly produced from sedimentary geothermal systems, plays an increasingly important role in direct energy use and provides an alternative energy source to fossil fuels in China. As the demand for direct use of sedimentary geothermal resources in China has been increasing in recent years, their sustainable utilization has become a requirement as well as a challenge for local geothermal production. Neogene Guantao sandstone geothermal reservoirs play an important role in geothermal utilization in China, mainly for space heating. However, due to heavy development and very limited recharge, fast water level drawdown occurs in most of the sandstone reservoirs in China once their utilization starts. Reinjection of the return water back into the underground has become an effective means to counteract the drawdown. This study is a part of an ongoing PhD project, aiming to contribute to the understanding of sustainable utilization of sandstone geothermal resources, in particular the reinjection of return water into sandstone reservoirs. In this paper, geological conditions, and property of the Guantao sandstone reservoir in North China basin will first be introduced. This is then followed by a description of Guantao sandstone geothermal production and reinjection history of the main production areas in North China basin.