Article
Geochemistry & Geophysics
Jun Ni, Hanming Gu, Yanghua Wang
Summary: Biot's theory of poroelasticity can describe seismic waves in fluid-saturated porous media, but the friction between the fluid and the solid skeleton has only a minor effect on the fast P-wave. To account for the viscoelasticity of the solid skeleton, a generalized viscoelastic wave equation is proposed, which effectively describes the dissipation characteristics of the waves.
Article
Geochemistry & Geophysics
Yury Alkhimenkov, Ludovic Rass, Lyudmila Khakimova, Beatriz Quintal, Yury Podladchikov
Summary: Biot's equations describe the theory of poroelasticity with wide applications, requiring high-performance computing for numerical solutions. Dimensional analysis reduces material parameters needed for experiments and emphasizes key parameters governing wave propagation in poroelastic media. High efficiency numerical implementation allows for investigation of three-dimensional and high-resolution scenarios.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geosciences, Multidisciplinary
Young-Kwang Choi, Fengyan Shi, Matt Malej, Jane M. Smith, James T. Kirby, Stephan T. Grilli
Summary: This study develops a multigrid-nesting interface for the Boussinesq wave model FUNWAVE-TVD. The interface manages the time sequencing and two-way nesting processes between the parent and child grids, ensuring workload balance and efficient data management.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2022)
Article
Astronomy & Astrophysics
Sarah Renkhoff, Daniela Cors, David Hilditch, Bernd Bruegmann
Summary: When a numerical simulation needs to deal with a physics problem that has a wide range of time-dependent length scales, dynamically adaptive discretizations can be the preferred method. A major upgrade to the numerical relativity code BAMPS is presented, incorporating fully adaptive, physics-agnostic hp refinement. The foundations of mesh refinement in the context of spectral element methods, the algorithm used for refinement in BAMPS, and several indicator functions used to drive it are described. The performance, scalability, and accuracy of the code in treating various 1D and 2D example problems are tested, demonstrating clear improvements over static mesh configurations. In particular, a simple nonlinear wave equation, the evolution of a real scalar field minimally coupled to gravity, and nonlinear gravitational waves are considered.
Article
Computer Science, Interdisciplinary Applications
Brandon Gusto, Tomasz Plewa
Summary: This study introduces a novel hybrid adaptive multiresolution (HAMR) approach to AMR-based calculations, which addresses the issue of unnecessarily high mesh resolution in regions adjacent to important solution features. By utilizing multiresolution smoothness indicators, the computational cost of individual physics solvers can be decreased through interpolation in smooth regions, resulting in improved performance of AMR codes.
COMPUTER PHYSICS COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
Ziqi Jin, Zhishui Liu, Ying Shi, Weihong Wang
Summary: Although seismic wave attenuation is frequency-dependent, most existing Q estimation methods assume that Q is constant. This limits the effective application of rock-physics Q models to link frequency-dependent Q estimations and rock properties. By employing suitable rock-physics modeling and scaling, a new frequency-dependent Q estimation method, called the two-parameters spectral ratio method, is developed. This method provides more accurate and reliable Q results by establishing a connection between rock-physic models, logging, and seismic data for better interpretation of subsurface properties.
Correction
Geosciences, Multidisciplinary
T. Kadeethum, S. Lee, H. M. Nick
Summary: A correction to the paper has been published.
MATHEMATICAL GEOSCIENCES
(2021)
Article
Mechanics
Sanghun Kim, Hossein Gorji, Eunji Jun
Summary: In the past decade, the particle-based Fokker-Planck (FP) method has been extensively studied to reduce computational costs. Different FP models have been proposed, but a comprehensive comparative study is needed. This paper investigates the accuracy and efficiency of four different FP models under rarefied conditions.
Article
Astronomy & Astrophysics
Milinda Fernando, David Neilsen, Yosef Zlochower, Eric W. Hirschmann, Hari Sundar
Summary: We present results from the new Dendro-GR code, which includes simulations of binary black hole mergers for mass ratios up to q = 16. The code utilizes wavelet adaptive multiresolution and an octree-based data structure to generate an unstructured grid adapted to the spacetime geometry. Validation of the code is achieved through comparisons to LazEv, demonstrating good scaling, improved convergence properties, and efficient usage of computational resources.
Article
Geochemistry & Geophysics
Yanbin He, J. German Rubino, Santiago G. Solazzi, Nicolas D. Barbosa, Marco Favino, Tianning Chen, Jinghuai Gao, Klaus Holliger
Summary: We propose a novel coupled fluid-poroelastic model and numerical upscaling procedure to calculate seismic attenuation and velocity dispersion in porous rocks induced by fluid pressure diffusion in the presence of mesoscopic fluid-saturated voids. The proposed approach shows advantages over purely poroelastic models in modeling fluid-saturated mesoscopic voids, and allows for the effects of different types of fluid pressure diffusion in the seismic characteristics of synthetic samples.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Enjiang Wang, Jiaxuan Yan
Summary: In this study, the seismic reflection dispersion from the ocean bottom separating seawater and heterogeneous porous seabed is investigated, taking into account the multi-scale fluid-flow losses and shear-wave attenuation. The analytical reflection coefficient based on displacement potentials and appropriate boundary conditions is obtained. The study considers two reflection scenarios, the water/water-bearing medium contact and the water/gas-saturated medium interface. Numerical results show the significant influence of P-wave mesoscopic attenuation, complex shear modulus, boundary conditions, and permeability on the frequency and angle dependence of reflection coefficients.
JOURNAL OF APPLIED GEOPHYSICS
(2023)
Article
Mathematics, Applied
Aycil Cesmelioglu, Jeonghun J. Lee, Sander Rhebergen
Summary: We introduce and analyze a hybridizable discontinuous Galerkin finite element method for the coupled Stokes-Biot problem. The method has the property that the discrete velocities and displacements satisfy the compressibility equations pointwise on the elements. We prove well-posedness of the discretization and provide a priori error estimates that demonstrate the method is free of volumetric locking. Numerical examples further demonstrate optimal rates of convergence for all unknowns and locking-free discretization.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2023)
Article
Geochemistry & Geophysics
Simon Lissa, Nicolas D. Barbosa, Beatriz Quintal
Summary: This study investigated the effects of fracture geometry on wave-induced fluid pressure diffusion by numerically computing seismic velocity and attenuation on models with realistic fracture geometries. Results show small discrepancies in the anisotropic behavior of P and S waves compared to a simple analytical model, with the exception of S wave attenuation. The dissipation caused by pressure gradients induced by S waves in mildly curved fractures suggests a potential method for inferring fracture hydraulic properties from S wave attenuation.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Mathematics, Applied
Rony Keppens, Jannis Teunissen, Chun Xia, Oliver Porth
Summary: MPI-AMRVAC is an open-source, block-grid adaptive framework for hyperbolic/parabolic partial differential equations. It can cover system PDEs of any dimensionality, and has recently added a parallel multi-grid solver for new avenues of extension.
COMPUTERS & MATHEMATICS WITH APPLICATIONS
(2021)
Article
Mathematics, Applied
Niklas Kolbe, Nikolaos Sfakianakis
Summary: In this paper, we present an administration technique for the bookkeeping of adaptive mesh refinement on (hyper-)rectangular meshes. The technique provides a unified approach for h-refinement in different dimensions, simplifies the identification of siblings and neighboring cells, and has a small memory footprint. Its applications include addressing h-refinement and its benefits in a specific 2D tumor growth and invasion problem.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2022)
Article
Geochemistry & Geophysics
Lucas Pimienta, Beatriz Quintal, Eva Caspari
Summary: While hydro-mechanical coupling in rocks explains how fluid-saturated rocks respond to pressure variations, the relationship between properties may not always be straightforward, especially in rocks with different pore types. The interdependence between mechanical and hydraulic properties, which differ based on pore families, can lead to underestimation of rock compressibility in poroelasticity experiments.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Zhiwei Xu, James Irving, Yu Liu, Peimin Zhu, Klaus Holliger
Summary: We have developed a stochastic inversion procedure for common-offset ground-penetrating radar (GPR) reflection measurements, capable of reliably recovering strongly heterogeneous porosity structures. Validation on synthetic and field data sets confirms the effectiveness of our method in recovering subsurface properties associated with alluvial aquifers.
Article
Geochemistry & Geophysics
Nicolas D. Barbosa, Andrew Greenwood, Eva Caspari, Nathan Dutler, Klaus Holliger
Summary: Using FWS log data, transmission losses across fractures can be quantified, and fracture compliance can be computed. The estimated mechanical compliance is consistent with previously reported values and may also help locate the most permeable fractures along a borehole.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Edith Sotelo, J. German Rubino, Santiago G. Solazzi, Nicolas D. Barbosa, Klaus Holliger
Summary: The study assesses the impact of damaged zones surrounding fractures on reflectivity and compliance, showing that the presence of damaged zones can enhance seismic reflectivity and normal compliance of fractures. This suggests that in largely impermeable environments, the seismic visibility of fractures can be improved through fluid pressure diffusion enabled by the presence of damaged zones.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Santiago G. Solazzi, Simon Lissa, J. German Rubino, Klaus Holliger
Summary: This study analyzes the seismic response of partially saturated cracks in rocks, taking into account the effects of squirt flow, and proposes and validates a simple analytical model. By handling the fluid bulk modulus and effective compliance matrix analytically, the mechanism of seismic response influenced by squirt flow is revealed.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Yu Liu, James Irving, Klaus Holliger
Summary: The proposed approach combines diffraction analysis and inversion of the reflected wavefield to estimate the detailed subsurface velocity structure from common-offset GPR reflection measurements. Testing and validation on synthetic data sets and a field example demonstrate the viability and robustness of the method. Additionally, the efficiency of the method in terms of field effort and computational cost allows for easy extension to 3-D, making it more attractive compared to multi-offset-based GPR velocity estimation techniques.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Yu Liu, Andrew Greenwood, Gyorgy Hetenyi, Ludovic Baron, Klaus Holliger
Summary: A high-resolution seismic reflection survey was conducted across the Insubric Line into the Ivrea-Verbano Zone to explore the structure of the lower continental crust. Through targeted drilling and data analysis, it was revealed that the prevalent sub-vertical structural grain in the lower continental crust may continue at the surface. The results show consistency between the synthetic and observed seismic data.
Article
Geochemistry & Geophysics
Gabriel E. Quiroga, J. German Rubino, Santiago G. Solazzi, Nicolas D. Barbosa, Klaus Holliger
Summary: Passive seismic characterization is an environmentally friendly method used to estimate the seismic properties of the subsurface. This study investigates the effects of fracture connectivity on Rayleigh wave velocity dispersion and incorporates wave-induced fluid pressure diffusion effects. The results show that fracture connectivity significantly affects the Rayleigh wave velocity.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
J. German Rubino, Nicolas D. Barbosa, Jurg Hunziker, Klaus Holliger
Summary: This study demonstrates for the first time that seismic reflection coefficients are highly sensitive to fracture interconnectivity, and suggests the use of crossplots of AVA coefficients to delineate fractured formations with different levels of fracture interconnectivity.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Yanbin He, J. German Rubino, Santiago G. Solazzi, Nicolas D. Barbosa, Marco Favino, Tianning Chen, Jinghuai Gao, Klaus Holliger
Summary: We propose a novel coupled fluid-poroelastic model and numerical upscaling procedure to calculate seismic attenuation and velocity dispersion in porous rocks induced by fluid pressure diffusion in the presence of mesoscopic fluid-saturated voids. The proposed approach shows advantages over purely poroelastic models in modeling fluid-saturated mesoscopic voids, and allows for the effects of different types of fluid pressure diffusion in the seismic characteristics of synthetic samples.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Zhenya Zhou, Eva Caspari, Nicolas D. Barbosa, Andrew Greenwood, Klaus Holliger
Summary: The compliance of mechanical fractures is important in various geoscientific applications. This study evaluates the potential of inferring the compliance of individual fractures from standard FWS data in the presence of background heterogeneity. The results show promising estimates using phase time delay method.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Gabriel E. Quiroga, J. German Rubino, Santiago G. Solazzi, Nicolas D. Barbosa, Marco Favino, Klaus Holliger
Summary: The presence of gaseous formation fluids in geothermal reservoirs and their effects on seismic velocities are important for geothermal energy production. This study proposes a poroelastic upscaling approach to accurately describe the physical processes in fractured reservoirs and differentiates changes in fracture density from changes in steam saturation using seismic velocity ratio analyses. The study also shows that Rayleigh-wave-based techniques can differentiate changes in fracture density from changes in steam saturation, and including fluid pressure diffusion effects is crucial for reliable detection and characterization of steam in fractured geothermal reservoirs.
Article
Physics, Fluids & Plasmas
Santiago G. Solazzi, Beatriz Quintal, Klaus Holliger
Summary: This work presents a numerical approach to model the attenuation and modulus dispersion of compressional waves due to squirt flow in porous media saturated by Maxwell-type non-Newtonian fluids. The results show that wave signatures strongly depend on the Deborah number, with larger values leading to increased attenuation and a shift towards higher frequencies.