Recently, projects have been proposed to engineer deep geothermal reservoirs in the ductile crust. To examine their feasibility, we performed high-temperature (up 1000 °C), high-pressure (130 MPa) triaxial experiments on granite (initially-intact and shock-cooled samples) which measured evolution of porosity during deformation. Mechanical data post-mortem microstuctural characterisation (X-ray computed tomography scanning electron microscopy) indicate that (1) failure mode was brittle up 900...

Earthquakes result from weakening of faults (transient decrease in friction) during co-seismic slip. Dry weaken due to degradation fault asperities by frictional heating (e.g. flash heating). In the presence fluids, theoretical models predict thermal pressurization fluid. However, experimental evidence rock/fluid interactions dynamic rupture under realistic stress conditions remains poorly documented. Here we demonstrate that relative contribution and depends on fluid thermodynamic...

Abstract Swarms are bursts of earthquakes without an obvious mainshock. Some have been observed to be associated with transient aseismic fault slip, while others thought related fluids. However, the association is rarely quantitative due insufficient data quality. We use high‐quality GPS/GNSS, InSAR, and relocated seismicity study a swarm >2,000 which occurred between 30 September 6 October 2020, near Westmorland, California. Using 5 min sampled Global Positioning System (GPS)...

Abstract Deterministic earthquake prediction remains elusive, but time‐dependent probabilistic seismicity forecasting seems within reach thanks to the development of physics‐based models relating stress changes. Difficulties include constraining nucleation model and fault initial state. Here, we analyze induced earthquakes from Groningen gas field, where production is strongly seasonal, began 3 decades after started. We use response variations constrain process calibrate for earthquakes....

Abstract A variety of geo‐energy operations involve extraction or injections fluids, including hydrocarbon production storage, hydrogen CO 2 sequestration, and geothermal energy production. The surface deformation resulting from such can be a source information on reservoir geomechanical properties as we show in this study. We analyze the time‐dependent Groningen region northeastern Netherlands using comprehensive geodetic data set, which includes InSAR (Radarsat2, TerraSAR‐X, Sentinel‐1),...

Abstract Today, earthquake precursors remain debated. While precursory slow slip is an important feature of nucleation, foreshock sequences are not always observed, and their temporal evolution remains poorly constrained. We report on laboratory earthquakes conducted under upper‐crustal stress fluid pressure conditions. The dynamics (slip, seismicity, fault coupling) prior to the mainshock dramatically affected by slight changes in conditions (fluid history). A relationship between moment...

Abstract Reservoir operations for gas extraction, fluid disposal, carbon dioxide storage, or geothermal energy production are capable of inducing seismicity. Modeling tools exist seismicity forecasting using operational data, but the computational costs and uncertainty quantification (UQ) pose challenges. We address this issue in context induced by from Groningen field an integrated modeling framework, which combines reservoir modeling, geomechanical stress-based earthquake forecasting. The...

In central Europe, many geo-energy reservoirs have revealed to be hosted in transverse isotropic crystalline rock, where the rock's mechanical and hydraulic transport properties are poorly constrained. Here, we performed triaxial experiments on Cresciano Gneiss samples under realistic stress (25–40 MPa) fluid pressure (5 conditions. We tested 5 different foliation orientations towards major principal (0, 30, 45, 60, 90°). During deformation, measured porosity evolution acoustic emission...

Abstract Understanding fluid flow in rough fractures is of high importance to large scale geologic processes and most anthropogenic geo‐energy activities. Here we conducted transport experiments on Carrara marble with a novel customized surface topography. Transmissivity measurements were under mechanical loading conditions representative deep geothermal reservoirs (normal stresses from 20 70 MPa shear 0 30 MPa). A numerical procedure simulating normal contact through complex geometries was...

Abstract Gas extraction from the Groningen gas reservoir, located in northeastern Netherlands, has led to a drop pressure and drove compaction induced seismicity. Stress-based models have shown success forecasting seismicity this particular context elsewhere, but they generally assume that earthquake clustering is negligible. To assess at Groningen, we generate an enhanced catalog using deep-learning-based workflow. We identify locate 1369 events between 2015 2022, including 660 newly...

Abstract Gas extraction from the Groningen gas field resulted in significant induced seismicity. We analyze magnitude‐frequency distribution of these earthquakes space, time and view stress changes calculated based on production reservoir properties. Previous studies suggested variations related to geometry stress. While we confirm spatial variations, do not detect a clear sensitivity b‐value Coulomb changes. However, find that correlates positively with rate This correlation is...

Abstract Seismological observations highlighted that earthquakes are often followed by changes in elastic properties around the fault zone. Here, we studied origin of these variations using stick‐slip experiments on saw‐cut granite samples presenting different degrees bulk damage (i.e., microcracks). Stick‐slip events were induced under triaxial compression configuration with continuous active ultrasonic measurements at confining pressures representative upper crustal conditions (15–120...

Understanding the micro-mechanisms underlying localized-ductile transition (LDT) as well brittle-plastic (BPT) has become crucial for our wider understanding of crustal processes and seismicity. Given how difficult in situ observations these transitions are to perform, laboratory experiments might be only way investigate active under conditions (high T high P). Here, we present Triaxial AppaRatus GEoThermal energy, a new gas-based triaxial apparatus located at EPFL Switzerland that was...

Gas extraction from the Groningen gas field resulted in significant induced seismicity. We analyze magnitude-frequency distribution of these earthquakes space, time and view stress changes calculated based on production reservoir properties. Previous studies suggested variations related to geometry decreasing b-value with increasing Coulomb stress. While we confirm spatial variations, do not detect a clear sensitivity However, find that correlates positively rate. This correlation is...

Today, observations of earthquake precursors remain widely debated. While precursory slow slip is an important feature nucleation, foreshock sequences are not always observed and their temporal evolution remains unconstrained. Here, we report on stick-slip experiments (laboratory earthquakes) conducted under seismogenic stresses in dry fluid pressure conditions. We show that the moment release scales with mainshock magnitude irrespective behavior (seismic or aseismic), presence fault's...

Reservoir operations related to natural gas extraction, fluid disposal, carbon diox- ide storage, or geothermal energy production, are capable of inducing seismicity. Mod- eling tools have been developed that allow for quantitative forecasting seismicity based on data, but the computational cost such models and difficulty in rep- resenting various sources uncertainties make uncertainty quantification challenging. We address this issue context an integrated modeling framework, which com-...

Understanding fluid flow in rough fractures is of high importance to large scale geologic processes and most anthropogenic geo-energy activities. Here, we conducted transport experiments on Carrara marble with a novel customized surface topography. Transmissivity measurements were under mechanical loading conditions representative deep geothermal reservoirs (normal stresses from 20 70 MPa shear 0 30 MPa). A numerical procedure simulating normal contact through complex geometries was...

Earth and Space Science Open Archive This is a preprint has not been peer reviewed. ESSOAr venue for early communication or feedback before review. Data may be preliminary.Learn more about preprints preprintOpen AccessYou are viewing the latest version by default [v1]Mechanical hydraulic transport properties of transverse-isotropic Gneiss deformed under deep reservoir stress pressure conditions.Authors Mateo Acosta iD Marie Violay See all authors AcostaiDCorresponding AuthorÉcole...

This paper investigates the behavior of permanent magnet synchronous machines paired with field-oriented control under effects asymmetric delay in per-phase current measurement and position effect. A mathematical model for 3-phase feedback was developed used to obtain theoretical step responses quadrature direct axes, as well root locus results dynamic system. Step were also obtained a simulated using Simulink, through experiments, while injecting varying levels delay. Increasing increasing...