New geophysical inversion and modeling tools developed by the PIXIL project have been applied to a conceptual model of the Garriga geothermal anomaly in Spain.
After two and a half years of research, the PIXIL (Pyrenees Imaging eXperience: an international network) project comes to an end. PIXIL is now the first cross-border network (Spain-Andorra-France) for subsoil characterization by “geophysical imaging” in the field of geothermal energy. The project was supported by five Spanish and French partners in different research areas – University of Barcelona, Basque Center for Applied Mathematics (BCAM), Pole Avenia, INRIA, and RealTime Seismic – as coordinated by the Barcelona Supercomputing Center.
Already in 2020, shortly after the start of the project, we reported on the PIXIL project for the first time. It was conceived as a transnational and multidisciplinary scientific and technological collaboration aimed at developing the most advanced tools for analyzing the subsurface of the earth, with a particular focus on promoting the use of geothermal energy in the region. “The project was 65% co-financed by the European Regional Development Fund (ERDF) through the Interreg VA Spain-France-Andorra programme.
“The PIXIL project managed to connect the academic and industrial sectors dedicated to geothermal energy. For two and a half years we have been able to refine technologies and conduct application demonstrations that would otherwise not have been possible,” said Josep de la Puente, head of the Barcelona Supercomputing Center geoscientific application group and coordinator of PIXIL.
“In addition, through working sessions open to the geothermal community, we have been able to address the issues of this technology with great future in our region. We hope to have contributed our grain of sand to geothermal energy being a complementary technology in the clean energy revolution of local origin,” added de la Puente.
Design of imaging algorithms for the characterization of geothermal reservoirs
PIXIL’s imaging algorithm design research has developed a new higher-order parallel modeling tool to simulate 3D magnetotelluric (MT) geophysical experiments. At the same time, researchers have developed deep neural networks (DNNs) aimed at solving the so-called inverse problem – how to determine the properties of the subsurface from recorded measurements. These DNNs have also been applied to the design of better downhole logging instruments.
In addition, research was conducted in collaboration with the industrial partner of the PIXIL project, RealTimeSeismic, to build a full-wave inversion (FWI)-based tool suitable for surface waves. The goal is to apply it to data collected by RealTimeSeismic in a shallow seismic survey.
Implementation in supercomputers for the geothermal sector
While designing innovative algorithms is critical to the effectiveness of imaging technologies, it is their computational implementation that gives the concept applicability. Therefore, PIXIL has also focused on implementing the developed methodological advances and converting them into fast, accurate and reliable computer programs.
The result of this effort was the latest version of PETGEM, a parallel code focused on detecting and characterizing geothermal reservoirs (and other valuable resources) using high-performance computing and electromagnetic methods. Thanks to PIXIL’s research, PETGEM has proven to be a scalable, flexible, accurate and efficient software for solving realistic test cases in both marine and terrestrial contexts. Additionally, PETGEM has been selected for the first pre-evaluation study of the R+D+I Energy for Society Network (XRE4S) Lab-to-Market (L2M) program, which will evaluate the technology and the opportunities it brings to the market .
Applications of technologies in geothermal energy
A key aspect of the PIXIL project was the ability to demonstrate the improvement of the developed technologies with real applications and experiments to quantify the results obtained. In particular, a reference model such as the La Garriga geothermal anomaly in the Vallés Oriental region of Catalonia was studied and reinterpreted to renew the existing conceptual model.
Thus, the new conceptual model integrates the geophysical results (obtained from electromagnetic, seismic, gravimetric and temperature data) with the geochemical, geological and hydrogeological ones. In this way it was possible to explore the mechanisms that control many of the geothermal systems present in the Pyrenees.
This case study served as inspiration for the models and tests of the new geophysical inversion tools developed within the PIXIL project. In addition, a collection of models of increasing complexity, inspired by a fault-controlled geothermal reservoir, was set up to test some of the numerical tools developed by the project partners.
Source: PIXIL project