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The pioneering work of Mike Batzle and his colleagues has provided a fundamental understanding of mechanisms behind dispersion and attenuation of elastic waves in fluid-saturated rocks. It also has made way for a realization that these phenomena need to be accounted for in a better way when...

Depletion or injection into a reservoir implies stress and strain changes in the reservoir and its surroundings. This may lead to measurable time-shifts for seismic waves propagating in the subsurface. We have measured multidirectional ultrasonic P-wave velocity changes for three different field...

Electrically induced or coupled transport processes including electrophoresis, electroosmosis and electromigration in solutions and porous media under an external electric field have been extensively studied and employed in many disciplines. For protection and rehabilitation of concrete structures...

Depletion or injection into a reservoir implies stress changes and strains in the reservoir and its surroundings. This may lead to measurable time-shifts for seismic waves propagating in the subsurface. To better understand the offset dependence of time-shifts in the overburden, we have...

Experimental studies of shale cores of different orientations have been performed to compare the angular dependence of dynamic moduli acquired at ultrasonic frequencies with static moduli (Young’s moduli and Poisson ratios) obtained during initial loading and during subsequent unload – reload cycles...

The quantitative estimation of rock physics properties is of great importance in any reservoir characterization. We have studied the sensitivity of such poroelastic rock physics properties to various seismic viscoelastic attributes (velocities, quality factors, and density). Because we considered a...

Successful utilization of petroleum resources requires proper monitoring of the subsurface, where time-lapse seismic is a prominent source of knowledge. The R-factor model is commonly used to model the strain sensitivity of 4D seismic data. Field cores are systematically tested with different...

Geomechanical anisotropy of shale overburden gives largely different estimates of stress and pore pressure changes which again impact on overburden 4D seismic response. The combined use of lab (static elastic moduli, Skempton parameters and velocities vs stress) and geomechanical modelling...

This poster presents a collaborative algorithmic framework for solving a set of different, yet similar, single-objective optimization problems. Common for these problems is that the evaluation of their objectives consists of two parts: The first part involves a computationally heavy task, like...

A comprehensive 3D finite difference time domain (FDTD) forward modeling based on idealized subsurface CO₂ resistivity distribution is carried out. The CO₂ is conceived in layers bounded above by impermeable shale layers. Additionally a 2.5D inversion of the modeled data is included in order to...

The static stiffness of a rock is generally smaller than its dynamic stiffness, which, for non-dispersive rocks, is due to a difference in strain amplitude in compaction tests (quasi-static) and wave-velocity measurements (dynamic). While acoustic waves are purely elastic, quasi-static mechanical...

This article presents a collaborative algorithmic framework that is effective for solving a multi-task optimization scenario where the evaluation of their objectives consists of two parts: The first part involves a common computationally heavy function, e.g., a numerical simulation, while the second...

Nanostructured ZrNiSn and ZrNiSn1−xSbx (x = 0.02 and 0.05) half-Heusler alloys were successfully synthesized via mechanical milling followed by spark plasma sintering. All samples crystallized in the expected MgAgAs-type crystal structure (space group 𝐹-43m) and retained their nanostructured powder...