Acoustic Emission Testing of Shales for Evaluation of Microseismic Monitoring of North Sea CO2 Storage Sites

Laboratory Evaluation of Mechanical Properties of Draupne Shale Relevant for CO2 Seal Integrity

“…At high stresses, ultrasonic velocities measured in the Draupne shale were less sensitive to stress changes due to its relatively stiffer framework owing to the lower organic content. Similar anisotropy in terms of compressional wave velocity for Draupne was observed from one undrained triaxial compression test on Draupne material conducted by Grande et al [26]. After creating a shear fracture on a vertical sample in the triaxial apparatus, they remobilized the fracture at progressively lower confining pressures while monitoring potential acoustic emission.…”

“…The Draupne shale is a major caprock of the North Sea and important in the assessment of potential CO 2 storage sites in the area [24]. Several recent publications have touched upon specific mechanical aspects of Draupne derived from testing on the same core material as in the current study (e.g., [25][26][27][28][29]). The first mention of the core was by Skurtveit et al [28] in 2015.…”

Induced-seismicity geomechanics for controlled CO2 storage in the North Sea (IGCCS)

“…East (Grande et al, 2020) and as such, the geomechanical behaviour may be distinctly different (i.e. over-consolidated vs. normally consolidated).…”

“…The geomechanical properties are compiled from extensive laboratory test data, both pre-existing (Grande and Cuisiat, 2008) and newly acquired in IGCCS (Mondol et al, 2018;CLIMIT, 2020;Grande et al, 2020, CLIMIT, 2020Griffiths et al, 2021); the laboratory data is upscaled through correlations with logs for the relevant North Sea lithologies (Horsrud, 2001). The compiled laboratory data includes those produced in IGCCS in order to obtain not only extended geomechanical properties of the North-Sea-specific materials at relevant stress levels and stress paths, but also AE responses and insights.…”

“…Our focus is particularly on the following fundamental mechanisms: (1) differences in geomechanical response between CO 2 and brine injections; and (2) thermal effects due to cold CO 2 injection. The current paper provides a brief summary of the main findings and learnings from IGCCS, and for more details, refers to the IGCCS-related publications of Bjørnarå et al (2021aBjørnarå et al ( , 2021b, CLI-MIT, 2020, Fawad and Mondol (2019), Grande et al (2020), Griffiths et al (2019Griffiths et al ( , 2021, Mondol et al (2018) and Mondol (2019).…”