Progress on a 300°C Directional Drilling System for EGS Well Installation

Abstract

Directional drilling is an essential service for well installation in an enhanced geothermal system (EGS) power facility. The array of injector and production wells must be accurately placed in the formation fracture system for efficient fluid circulation and heat production. Current commercial offerings for directional drilling systems are rated for 175°C (347°F) service while demands of the EGS drilling environment require operation for significant periods at temperatures up to 300°C (572°F). Two US Department of Energy Geothermal Technologies Program (GTP) projects have been initiated to develop a 300°C (572°F)-capable directional drilling system consisting of a drill bit, directional motor, fluid and navigation with telemetry system. In this paper, the authors review progress towards the project deliverables to develop, fabricate and field test the system. The drill bit, motor and fluid are in the process of completing fabrication and there are plans to drill a directional well in granite at a test rig in Oklahoma later this year. The navigation system is undergoing a feasibility study on 300°C (572°F) sensors, electronics, active cooling and telemetry subcomponents.