Next-generation geothermal has a reputation problem: people assume the challenge is heat. It isn't. The heat is there. The hard part is hitting the target, connecting two wellbores precisely, thousands of feet underground. That is a ranging problem, and it is already solved.
What closed-loop actually requires
A closed-loop geothermal system circulates fluid through a sealed underground loop to harvest heat without producing reservoir fluids. To form that loop, two wells must intersect, or be connected, at depth with high precision. Enhanced systems add a further demand: multiple wellbores spaced exactly to access specific zones of a heat reservoir.
At the depths involved, conventional directional surveys are not accurate enough to guarantee that connection. Miss it, and the loop doesn't close, and the project's economics collapse with it.
Borrowed from the hardest wells in oil & gas
Intentionally intersecting one wellbore with another is not new. It is the same physics that makes relief wells, SAGD well pairs and coal-bed-methane intersect drilling possible. Magnetic ranging has guided those connections for decades.
Active ranging, well to well
Gunnar applies active ranging, including the Torped™ rotating-magnet source, to connect one wellbore precisely to another. The sensor is deployed in one drilling well and the source in the next, and the twin drilling BHAs effectively talk to each other magnetically, measuring their exact separation all the way along the parallel section and then to the intercept point. The result is a deterministic connection where conventional steering offers only a slim chance of success.
That precision unlocks designs that were previously impractical: tighter loops, multi-lateral collectors, and reservoir spacing tuned to the resource.
A toolset for the geothermal engineer
Gunnar's leadership has detailed this crossover at venues including the Geothermal Resources Council and in coverage by ThinkGeoEnergy, positioning magnetic ranging as a core capability the geothermal drilling engineer can now design around, not a workaround, but a foundation.
- Closed-loop geothermal depends on connecting wellbores precisely at depth.
- With conventional surveying it's impossible; only ranging can guarantee the connection.
- The physics is proven, it's how relief-well pairs are drilled.
- Active ranging, including Torped™, makes and holds the connection well to well.