Pitt research receives funding for stress characterization in geothermal reservoirs

Pitt research receives funding for stress characterization in geothermal reservoirs Associate Professor Andrew Bunger, Principal Investigator, stands in front of his lab equipment (source: University of Pittsburgh)
Carlo Cariaga 18 Aug 2022

A team of engineers at the University of Pittsburgh are doing lab-scale experiments on stress characterization to support the Utah FORGE project.

A team of engineers at the University of Pittsburgh (Pitt) are working on research that aims to characterize the stress in the rock formation targeted by the Utah Frontier Observatory Research in Geothermal Energy (FORGE). To this end, the Pitt team has received a USD 1.26M grant from the U.S Department of Energy for two collaborative projects.

Being able to predict how a rock formation will react to stress as a result of drilling, fluid injection, and high temperatures is an important element of assessing a reservoir in terms of productivity and sustainability.

“Because geothermal wells are deep and expensive, you need to circulate large volumes of water for the energy produced to be  economically viable,” said Associate Professor of Civil and Environmental Engineering and Principal Investigator Andrew Bunger. “Designing these systems is difficult if you don’t know how the rock will react as the wells are drilled and you can’t simply dig a hole to collect a sample.”

Direct data collection is also difficult, as the temperatures encountered in geothermal wells are typically to hot for underground sensors. Thus, the research team is focusing on developing lab-based estimates of stresses that are analyzed hand-in-hand with in-situ measurements.

The lab-based method involves analyzing the rock cores that have been extracted from the formation targeted by the Utah FORGE project. This data complements the data collected by lead partner Battelle Memorial Institute from downhole measurement using the more traditional methods. Based on both experimental data and stress tests, minimum and maximum stress values can be estimated and compared with other models.

The team is also working with scientists at the Lawrence Livermore National Laboratory to create high-fidelity estimates of in-situ stress using a combination of lab-based data and subsurface measurements. The lab-based experiments done by Bunger’s team will provide new insight not previously available through other methods.

“The work we’re doing with Utah FORGE is really exciting because we’re using the best technology available to help fill knowledge gaps. Innovation always requires iteration, so you get better as you go,” commented Bunger.

“The prize is huge with geothermal, but we have to be much more sophisticated in our methods  than ever before if we are going to develop it to the point we can rely on it to significantly contribute to our renewable energy portfolio. Funding like this gives us the space and resources to innovate so we can tap into this resource.”  he further added.

Earlier this year, the IGC Webinar series hosted a webinar with Dr. John McLennan, co-principal investigator of the Utah FORGE project, where he discussed updates on the project’s recent activities. We have published a recap of this webinar’s highlights.

Source: University of Pittsburgh