Development of Multi-Stage Fracturing System and Wellbore Tractor to Enable Zonal Isolation During Stimulation and EGS Operations in Horizontal Wellbores

Abstract

Abstract This paper discusses the progress on a project funded by the DOE Utah FORGE (Frontier Observatory for Research in Geothermal Energy) for the development of a subsurface heat exchanger for Enhanced Geothermal Systems (EGS) using unique casing sleeves cemented in place and are used first as a system for rapid and inexpensive multi-stage stimulations and second to perform conformance control functions at 225 °C. The proposed sleeves will use a single-sized dissolvable ball to open for fracture stimulation. After stimulation, and once the balls dissolve, the sleeves are open for immediate fluid injection. A separately designed wellbore tractor specific for both fluid detection and valve manipulation is then deployed to detect and control the injection entry points to create an effective EGS through paired horizontal injectors and open hole producers. The wells will be connected through multiple networks of induced and natural fractures that can be controlled throughout the field life.