Development and Design of High-angle Deviated Geothermal Well Extraction and Reinjection in Sandstone Types Thermal Storage

Abstract

High-angle deviated wells have a larger contact area with the reservoir compared to conventional vertical wells. As extraction and injection wells, they can significantly enhance extraction efficiency. Additionally, an integrated geological engineering design allows for large platform implementation, reducing surface construction costs and increasing overall project returns. However, due to the inter-layer and intra-layer heterogeneity of sandstone types thermal storage, high-angle deviated wells are prone to issues such as uneven vertical utilization and cold breakthrough in high-permeability layers. Moreover, predicting water extraction temperatures becomes more challenging. This paper is based on implemented project examples to optimize the design of high-angle deviated geothermal wells and screen casing. The integrated geological engineering approach aims to reduce costs and increase efficiency by optimizing well trajectories considering inter-layer heterogeneity, ensuring effective water extraction deeply. Additionally, we establish a QS flow equation and use the harmonic level KH method for temperature prediction, achieving a 10% increase in thermal storage thickness utilization with measurement and temperature errors within 3%. A modeling system for thermal storage temperature fields throughout the lifecycle is developed, providing a solid foundation for parameter optimization in project planning. Real-time monitoring of field operations is conducted to provide early warnings for cold breakthrough risks, ensuring stable operation of public welfare projects.