The Geothermal Technologies Office’s (GTO) largest initiative, the Frontier Observatory for Research in Geothermal Energy (FORGE), is breaking ground – literally – in new and exciting ways!
After years of planning, team building, and site preparation, the FORGE team, led by researchers at the University of Utah, launched its much-anticipated drilling phase at the Utah FORGE site last fall. Cutting-edge geothermal projects like FORGE can unlock access to a domestic, low-carbon, clean energy source with the potential to supply power to tens of millions of homes in the United States. This phase represents an unprecedented scale of research that could pivot the geothermal industry toward a real reduction in geothermal energy development costs.
The Utah FORGE team drilled the first production/injection well vertically through approximately 4,700 feet of sediments before penetrating into the crystalline granite basement. At this point, the well was gradually steered to 65°; a deviation that was maintained to the bottom of the well (true vertical depth of 8,559 ft and a total measured depth of 10,987 ft). Not only is this a complex, highly deviated well, the temperature of the “toe” of the well is approximately 228°C (442°F). Directional drilling at high-temperatures is difficult and is seldom done in geothermal development. To meet these challenges head-on, the Utah FORGE team approached this drilling phase methodically by combining new, state-of-the-art approaches and tools with a range of risk and technical maturity, driven by a large, multi-disciplinary team that borrowed best practices and lessons learned from adjacent industries such as oil and gas.
Some of these approaches and tools include the collection of an extraordinary dataset from sophisticated, high temperature logging and in-situ stress testing to inform decisions. Drillers used fixed cutter polycrystalline diamond compact (PDC) bits, used routinely by oil and gas drillers because of their proven track record of significantly increasing drilling rates. Partnering with Texas A&M University awardees via GTO’s Efficient Drilling for Geothermal Energy (EDGE) initiative, the Utah FORGE team used “physics-based limiter redesign workflows” in which Texas A&M provided drilling workflow training and consulting services throughout the drilling of the well.
Despite the technical challenges presented, this well was completed in about one-half the time initially planned with the help of these advanced approaches and tools that can be emulated at other geothermal drilling sites. The Utah FORGE team originally planned for 136 days from the beginning of drilling to release the rig, but ultimately the rig was released just 74 days after drilling began. Adding another layer of complexity to the drilling operations, the team collected approximately 74 feet of valuable metamorphic and granitic core, which will be made available to the scientific community. The remarkable drilling of this injector/producer well demonstrates what can be achieved by the geothermal industry using state-of-the-art drilling approaches and tools.
The University of Utah team comprised of experts in geothermal development drilling; extended reach drilling specialists and experts in oil and gas; and early planning meetings with “drilling on paper” exercises, executed to ensure plans were scrutinized and understood by all team members.
The next steps at the Utah FORGE site include analysis of the reservoir rock and planning before stimulation of a “greenfield” reservoir this summer, and an announcement of the first Utah FORGE R&D solicitation awards. These awardees will be the first scientists and technologists to test and deploy more advanced geothermal tools and techniques.
Please visit the Utah FORGE website and follow their social media for further exciting updates.