Geothermal Geosteering

Feb 20, 2020

Stephen Clark
Senior Technical Analyst, ROGII

Geothermal is not generally something that gets much press in the renewable energy discussion. Historically, it has only been viable in regions with a shallow heat source and porous, permeable rock for water to flow through. This only leaves a handful of places in the world where geothermal energy can function at commercial levels. Eavor Technologies out of Calgary has leveraged unconventional petroleum technologies in horizontal drilling as well as Rogii’s StarSteer geosteering software to potentially expand the geothermal commercial envelope exponentially.

Eavor’s technology consists of creating a closed loop system of subsurface wells which takes advantage of a thermosiphon effect whereby hot fluids rise in the inlet well while cool fluids fall in the outlet well. In order for all of this to happen, two mirror image horizontal wells must be drilled to sufficient depth and steered to connect at their toe in the subsurface. The precision geosteering required to do this was provided by Chinook Consulting out of Calgary. Additionally, specialized magnetic ranging sensors (a technology widely used in thermal oil developments) were used to provide terminal intersection guidance once the wellbores were within 30 meters of each other. The importance of precision geosteering towards the successful intersection of 2 wellbores 2+ km underground can’t be overstated. Inherent directional survey rounding errors and the wells’ cones of uncertainty are common challenges when navigating reservoirs with horizontal wells. “Precision geosteering throughout the lateral sections allows the two wellbores to head at each other at the same stratigraphic level, setting the stage for magnetic ranging in the later stages of intersection,” Calin Dragoie of Chinook explained.

Well overlay across Calgary (photo credit: Chinook Consulting)

Well overlay across Calgary

This innovative application of unconventional petroleum technologies like horizontal drilling, advanced mud systems, magnetic ranging sensors, and StarSteer could allow geothermal energy to greatly expand its potential footprint and scale up the energy intensity of geothermal developments. Further, the ability to sidetrack and connect mirror-image daughter wells from both the inlet and outlet wells allows for the scaling of this technology to be customized to suit the area it is meant to service.

For more information on Eavor Technologies, Chinook Consulting, or Rogii (StarSteer), please visit their respective websites: