3-D-geomechanical-numerical model of the contemporary crustal stress state in the Alberta Basin

Abstract

Abstract. In the context of examining the potential usage of safe and sustainable geothermal energy in the Alberta Basin whether in deep sediments or crystalline rock, the understanding of the in-situ stress state is crucial. It is a key challenge to estimate the 3-D stress state at an arbitrary chosen point in the crust, based on sparsely distributed in-situ stress data. To address this challenge, we present a large-scale 3-D geomechanical-numerical model (700 km × 1200 km × 80 km) from a large portion of the Alberta Basin, to provide a 3-D continuous quantification of the contemporary stress orientations and stress magnitudes. To calibrate the model, we use a large database of in-situ stress orientation (321 SHmax) as well as stress magnitude data (981 SV, 1720 SHmin and 2 (+11) SHmax) from the Alberta Basin. To find the best-fit model we vary the material properties and primarily the kinematic boundary conditions of the model. This study focusses in detail on the statistical calibration procedure, because of the large amount of available data, the diversity of data types, and the importance of the order of data tests. The best-fit model provides the total 3-D stress tensor for nearly the whole Alberta Basin and allows estimation of stress orientation and stress magnitudes in advance of any well. First order implications for the well design and configuration of enhanced geothermal systems are revealed. Systematic deviations of the modelled stress from in-situ data are found for stress orientations in the Peace River- and the Bow Island Arch as well as for leak-off-test magnitudes.

A revised crustal stress orientation database for Canada

“…Camelbeeck et al, 2013;Flesch et al, 2007;Naliboff et al, 2012). Recent modelling of upper crustal stress orientation and magnitude in the Alberta Basin demonstrates less influence of Mohorovičić depthvariation below the Rocky Mountains (Reiter and Heidbach, 2014).…”

Crustal Fault Zones (CFZ) as Geothermal Power Systems: A Preliminary 3D THM Model Constrained by a Multidisciplinary Approach

“…Indeed, based on the tectonic history (see Figure 2) and the measurements acquired in the field, different fault families have been individualized. The complete mesh consists One of the critical points in setting up regionally scaled mechanical models are the boundary conditions [96,97] that result from the far-field stresses. The overall stress orientation is often hinted from the integration of several measurements in a given region (such as well tests and GPS measurement).…”