A5058689845- Seismic Imaging and Inversion Techniques
- Hydraulic Fracturing and Reservoir Analysis
- Drilling and Well Engineering
- Rock Mechanics and Modeling
- Seismic Waves and Analysis
- Geophysical Methods and Applications
- Ultrasonics and Acoustic Wave Propagation
- Groundwater flow and contamination studies
- Geotechnical and Geomechanical Engineering
- Seismology and Earthquake Studies
- Landslides and related hazards
- Enhanced Oil Recovery Techniques
- Lattice Boltzmann Simulation Studies
- Hydrocarbon exploration and reservoir analysis
- Geotechnical Engineering and Underground Structures
- Fatigue and fracture mechanics
- Grouting, Rheology, and Soil Mechanics
- Geological Modeling and Analysis
- Methane Hydrates and Related Phenomena
- Mineral Processing and Grinding
- CO2 Sequestration and Geologic Interactions
- Earthquake Detection and Analysis
- Geophysical and Geoelectrical Methods
- Photochromic and Fluorescence Chemistry
- Photonic and Optical Devices
Purdue University West Lafayette
2016-2025
Purdue University System
2019
Sandia National Laboratories California
2019
Purdue Research Foundation
2001
University of Notre Dame
1992-1997
University of California, Berkeley
1988-1993
Lawrence Berkeley National Laboratory
1987-1988
NASA Earth Science
1987
Abstract Fracture pattern development has been a challenging area of research in the Earth sciences for more than 100 years. Much learned about spatial and temporal complexity inherent to these systems, but severe challenges remain. Future advances will require new approaches. Chemical processes play larger role opening‐mode fracture hitherto appreciated. This review examines relationships between mechanical geochemical that influence patterns recorded natural settings. For fractures formed...
Abstract Quantitative predictions of natural and induced phenomena in fractured rock is one the great challenges Earth Energy Sciences with far‐reaching economic environmental impacts. Fractures occupy a very small volume subsurface formation but often dominate fluid flow, solute transport mechanical deformation behavior. They play central role CO 2 sequestration, nuclear waste disposal, hydrogen storage, geothermal energy production, nonproliferation, hydrocarbon extraction. These...
Many rock structures include multiple, near‐parallel, planar discontinuities such as bedding planes or joints. The effects of these nonwelded interfaces on seismic wave propagation are often analyzed using effective moduli, in terms which is independent frequency and without loss, unless the moduli imaginary terms. An alternative approach to treat a boundary condition equation, across stress continuous, but particle displacements discontinuous. ratio displacement called specific stiffness...
A goal of subsurface geophysical monitoring is the detection and characterization fracture alterations that affect hydraulic integrity a site. Achievement this requires link between mechanical properties fracture. Here we present scaling relationship fluid flow fracture-specific stiffness approaches universality. Fracture-specific property dependent on geometry can be monitored remotely using seismic techniques. Monte Carlo numerical approach demonstrates exists for fractures with strongly...
Earthquake prediction, the long-sought holy grail of earthquake science, continues to confound Earth scientists. Could we make advances by crowdsourcing, drawing from vast knowledge and creativity machine learning (ML) community? We used Google’s ML competition platform, Kaggle, engage worldwide community with a develop improve data analysis approaches on forecasting problem that uses laboratory data. The competitors were tasked predicting time remaining before next successive quake events,...
Large deviations from "cubic‐law" dependence of laminar fluid flow through fractures on the apparent mechanical aperture a fracture can be explained by assuming: 1) cubic‐law actual local at microscopic level; 2) conservation rock volume when deforming fracture; and 3) macroscopic properties are dominated critical neck (the smallest along path highest fracture).
In this paper the author presents a survey of current understanding interrelationships among hydraulic, mechanical, seismic and geometrical properties single natural factures. The also includes discussion methods that have been developed to improve measurement fracture geometry including specific stiffness, which is key link in interrelating physical fracture. A new approach for determining shear stiffness uses interface waves propagate along fractures. (A)
Using transparent microfluidic cells to study the two‐phase properties of a synthetic porous medium, we establish that interfacial area per volume between nonwetting and wetting fluids lifts ambiguity associated with hysteretic relationship capillary pressure saturation in media. The interface phases is composed two subsets: one unique curvature determined by pressure, other distribution curvatures dominated disjoining pressure. This work provides experimental support for recent theoretical...
Development of pore network models based on detailed topological data the space is essential for predicting multiphase flow in porous media. In this work, an unstructured model has been developed to simulate a set drainage and imbibition laboratory experiments performed two‐dimensional micromodel. We used pixel‐based distance transform determine medial pixels void domain This process provides assembly with assigned local widths that simulates topology medium. Using model, capillary...
Non‐welded interfaces can be treated as a displacement discontinuity characterized by elastic stiffnesses. Applying this boundary condition to generalized Rayleigh wave, it is shown that fast and slow dispersive wave propagate along the fracture, even when seismic properties of rock on each side are identical.
Abstract Active geophysical monitoring of potential failure along mechanical discontinuities in rock requires identification precursory signatures to signals. ultrasonic shear frictional was performed determine the failure. An instrumented direct apparatus used apply a constant shearing rate discontinuity that held under normal stress. Transmitted and reflected compressional waves were recorded during process. Ultrasonic precursors identified as distinct maxima amplitude transmitted well...
[1] Seismic characterization of fluid flow through fractures requires a fundamental understanding the relationship between hydraulic and mechanical properties fractures. A finite-size scaling analysis was performed on with weakly correlated random aperture distributions to determine fracture stiffness flow. From computer simulations, dynamic transport exponent, which provides power law dependence, extracted used collapse flow-stiffness relationships from multiple scales into single function....
In the last few decades, micro-models have become popular experimental tools for two-phase flow studies. this work, design and fabrication of an innovative, elongated, glass-etched micro-model with dimensions 5 × 35 mm(2) constant depth 43 microns is described. This first time that a such has been etched in glass by using dry etching technique. The was visualized novel setup allowed us to monitor record distribution fluids throughout length continuously. Quasi-static drainage experiments...
We develop an approach for simulating acousto-elastic wave phenomena, including scattering from fluid–solid boundaries, where the solid is allowed to be anisotropic, with discontinuous Galerkin method. use a coupled first-order elastic strain-velocity, acoustic velocity–pressure formulation, and append penalty terms based on interior boundary continuity conditions numerical (central) flux so that consistency condition holds discretized weak formulation. incorporate boundaries through these...
We use x‐ray computerized tomographic (CT) imaging to present quantitative aperture data for three‐dimensional interconnected fracture networks imbedded in intact opaque rock samples several centimeters length. X‐ray images are obtained by injecting a high‐density liquid metal into the fractured specimen under lithostatic conditions. The combination of reconstruction with gravimetric analysis makes it possible first time obtain effective sizes an accuracy only microns, located spatially...
We investigate experimentally the functional relationship between capillary pressure, P c , wetting phase saturation, S w and interfacial area per volume nonwetting phases, a wn for drainage imbibition processes in micromodels of two‐dimensional pore structures. Within experimental analysis error (around 10–15%), resulting ‐ surfaces were same. This suggests that data obtained from either process or are sufficient to generate complete among observed hysteresis can be modeled by including as...
Abstract A model formulated in terms of both conservation and kinematic equations for phases interfaces two‐fluid‐phase flow a porous medium system is summarized. Macroscale are derived as extensions averaging theorems do not rely on principles. Models based can describe multiphase with varying fidelity. When only phase‐based considered, similar form to the traditional results. interface also included, novel formulation results that naturally includes evolution express dynamic changes fluid...