About an hour north of Houston, NOV recently drilled an 11,500-ft-deep closed-loop geothermal test well, one of the newest of its kind.
The drilling and completions technology provider hosted a multicompany forum at the site in January, drawing other industry players that are collaborating to successfully develop the technology.
Unlike traditional geothermal systems that rely on natural hydrothermal resources, closed-loop geothermal (CLG) systems use a sealed underground loop to circulate a working fluid. This fluid absorbs heat from the hot rock formations underground and transports it to the surface for energy generation or direct heating.
Chuck Wright, NOV’s corporate director of research and development, told guests during the visit that NOV’s initial focus was on creating a medium-sized facility with a 1,500-hp drilling rig and a 20,000-ft vertical capability, but the facility has since expanded beyond drilling operations to include a “completions playground” with coiled tubing operations and 70 wells across the north and south pads that can be repurposed for geothermal tests.
NOV’s test well, initially planned to reach 12,000 ft, was completed at 11,500 ft, said Wright. Despite the adjustment, the well reached 278°C (532°F), surpassing the required 250°C (480°F) and marking a successful test.
The results highlight both the progress and remaining challenges in geothermal technology, underscoring the need for further upgrades in the field.
The facility’s design includes options for supercritical fluids transport and preservation, though these elements have not yet been implemented. NOV is also looking at ways to incorporate more digital solutions at the wellsite in an effort to promote data sharing and collaboration throughout the industry.
Project Collaboration
The potential for CLG systems is considered to be expansive on a technical basis, with ongoing research and development aimed at optimizing performance and expanding its commercial application. Companies including Greenfire Energy, which took part in NOV’s demonstration event, are among those betting big on the potential of CLG technology.
GreenFire is the developer of an integrated subsurface, wellbore, and surface modeling system that estimates the net power from a given asset.
Other solution providers included Vallourec, which showcased its vacuum-insulated tubulars that feature an integrated fiber-optics system to measure temperature data and estimate bottomhole fluid temperature.
NOV is working as a systems integrator with these companies, embracing collaboration to advance its geothermal prospects.
Perhaps the biggest question still unanswered on CLG involves its cost efficiency. Skeptics argue that heat conduction in these types of geothermal wells transfers energy into the wellbore too slowly, resulting in low power output per foot of wellbore.
Added Efficiency
However, Wright and others championing CLG are confident that innovations in robotics and automation can create more efficiencies and bring costs down by speeding up key processes.
“Geothermal on the drilling side, has lagged a little bit on some of the efficiencies that have been found in the oil and gas space that haven’t translated into geothermal,” he said.
"The digital aspect has been a component of the field, but there is a desire to move things along, and that’s all speaking to efficiencies. And the oil and gas has been driving efficiencies.”
And while automation and development of the digital components of the technology can add greater efficiency to the wellsite, even more can be achieved by managing reservoir temperatures which correspondingly reduce the levelized cost of electricity (LCOE), John Clegg, president and CTO of Hephae Energy, said during a panel at the NOV test site.
“Levelized cost of electricity is a function of a number of things, but one of those is reservoir temperature,” he said. “We did a bunch of modeling and we realized this tremendous leverage in terms of cost of electricity versus reservoir temperature … from 200°C to 300°C, you don’t get reductions in electricity of a few percent, but rather in the 50% range.”
Such cost-efficiency leverage would encourage future projects.
Most commercial tools are specified for temperatures of up to 175°C to 185°C, with very few working effectively at or beyond 200°C.
One forum speaker noted that many tools designed to work within these ranges fail well below them—at around 120°C to 140°C—raising concerns about reliability in geothermal applications.
During drilling operations, the temperature inside measurement-while-drilling tools can rise rapidly when circulation stops (e.g., during connections or tripping). This affects the tools’ reliability and lifespan.
“The reliability of electronics is governed by the rule of thumb: for every 10°C increase in temperature, you approximately halve the reliability. Conversely, if you go down in temperature, you double the reliability,” Clegg said.
NOV’s collaboration with industry partners underscores the oil and gas sector’s push into geothermal energy. However, CLG’s broader adoption will depend on further advancements in automation and digital technology, as well as proving its economic viability.
