A5062477306- Geophysical and Geoelectrical Methods
- Geophysical Methods and Applications
- Seismic Waves and Analysis
- Seismic Imaging and Inversion Techniques
- Model-Driven Software Engineering Techniques
- Non-Destructive Testing Techniques
- Geological Modeling and Analysis
- Seismology and Earthquake Studies
- Earthquake Detection and Analysis
- Computational Physics and Python Applications
- Scientific Research and Discoveries
- Magnetic Field Sensors Techniques
- Geophysics and Gravity Measurements
- Geophysics and Sensor Technology
- Sensor Technology and Measurement Systems
- Comparative Literary Analysis and Criticism
- Material Properties and Processing
- Manufacturing Process and Optimization
- Ionosphere and magnetosphere dynamics
- Mineral Processing and Grinding
- Consumer Packaging Perceptions and Trends
- Eosinophilic Disorders and Syndromes
- NMR spectroscopy and applications
- Embedded Systems Design Techniques
- Methane Hydrates and Related Phenomena
Delft University of Technology
2018-2024
Mexican Institute of Petroleum
2017
Geophysical Laboratory
2017
University of Edinburgh
2012-2014
Petroleum Geo-Services (United Kingdom)
2009
The Python-code empymod computes the 3D electromagnetic field in a layered earth with vertical transverse isotropy by combining and extending two earlier presented algorithms this journal. bottleneck frequency- time-domain calculations of responses derived wavenumber-frequency domain is transformations from wavenumber to space frequency time domain, so-called Hankel Fourier transforms. Three different transform methods (quadrature, quadrature-with-extrapolation [QWE], filters) four (fast...
We developed a methodology to estimate resistivities from seismic velocities. applied known methods, including rock physics, depth trends, structural information, and uncertainty analysis. The result is the range of background resistivity models that consistent with successfully tested real data North Sea. These 2D or 3D yield detailed insight into resistivity, they are powerful tool for feasibility studies. They could also serve as starting constraints in (iterative) forward modeling...
Large-scale modelling of three-dimensional controlled-source electromagnetic (CSEM) surveys used to be feasible only for large companies and research consortia. This has changed over the last few years, today there exists a selection different open-source codes available everyone. Using four in Python ecosystem, we perform simulations increasingly complex models shallow marine setting. We first verify computed fields with semi-analytical solutions simple layered model. Then validate...
Data Assimilation combines computer models with real-world measurements to improve estimates and forecasts of dynamical systems such as oceans, atmosphere, subsurface reservoirs. The Python package dageo is a tool apply data assimilation in geoscience applications. Currently, it encompasses the Ensemble Smoother Multiple (ESMDA) method provides tools for reservoir engineering includes localization help relatively small ensembles, Gaussian random field generation generating heterogeneous...
Controlled-source electromagnetic (CSEM) surveys are a common geophysical investigation tool in the search for, amongst other, groundwater, hydrocarbons, and minerals.The numerical modelling of CSEM data requires solution Maxwell equations.These can be simplified particular case CSEM, as frequencies used usually sufficiently low to ignore any displacement currents.A diffusive problem remains, which has resulting system equations given frequency domain bywhere η = iωµ 0 (σ -iωε).The electric...
Electric currents induced in conductive planetary interiors by time-varying magnetospheric and ionospheric current systems have a significant effect on electromagnetic (EM) field observations. Complete characterization of EM induction effects is difficult owing to non-linear interactions between the three-dimensional (3-D) electrical structure planet spatial complexity inducing systems. We present general framework for time-domain modeling 3-D heterogeneous conducting planets. Our approach...
Ocean-bottom seismometers (OBSs) are equipped with seismic sensors that record acoustic and events at the seafloor, which makes them suitable for investigating tectonic structures capable of generating earthquakes offshore. One critical parameter to obtain accurate earthquake locations is absolute time incoming signals recorded by OBSs. It is, however, not possible synchronize internal clocks OBSs a known reference time, given GNSS unable reach instrument sea bottom. To address this issue,...
The open-source code fdesign makes it possible to design digital linear filters for the Hankel and Fourier transforms used in potential, diffusive, wavefield modeling. Digital can be derived any electromagnetic (EM) method, such as methods diffusive limits (direct current, controlled-source EM [CSEM]) well using higher frequency content (ground-penetrating radar [GPR], acoustic elastic wavefields). direct matrix inversion method is derivation of filter values, a brute-force minimization...
SUMMARY 3-D controlled-source electromagnetic data are often computed directly in the domain of interest, either frequency or time domain. Computing it one and transforming via a Fourier transform to other is viable alternative. It requires evaluation many responses computational if standard transforms used. This can make prohibitively expensive kernel time-consuming as case modelling. The speed modelling obtained through such defined by three key points: solver, method implementation...
We created a workflow to predict controlled-source electromagnetic (CSEM) responses from seismic velocities and compared the predicted with CSEM data. The first step was calculate resistivity model in Bayesian framework account for uncertainties. second estimate electric anisotropy improve depths at which there no well control. last use this updated forward-model compare result comparison real data revealed that measured were generally within plus minus one standard deviation of responses....
Forward modeling is an important part of understanding controlled-source electromagnetic (CSEM) responses. The diffusive term in the wave equation dominant over displacement at these frequencies. It behavior that makes it difficult to imagine actual propagation signal. An tool gaining experience therefore forward modeling, and lots it. advantage one-dimensional (1D) besides its speed, study isolated effects (see for instance Key, 2009): What influence resistivity anisotropy, or fine-scale...
Geothermal heat production might pose the risk of degrading groundwater quality due to temperature changes, which may lead ecological and economic impacts. Monitoring quantifying spatial temporal changes in are challenging but necessary for reliable environmental evaluations. Electromagnetic Induction (EMI) measurements have been extensively used monitoring, since Electrical Conductivity (EC) is very sensitive properties, such as presence contaminants or fluid temperature. Subsurface EC...
The data assimilation process for geothermal reservoirs often relies on well data, which primarily offer insights into the immediate vicinity of borehole. However, integrating geophysical methods can provide valuable information beyond proximity, possibly enhancing reservoir predictions. Current monitoring struggle to maintain a good signal-to-noise ratio deep reservoirs. Diffusive electromagnetic (EM) be sensitive decreasing conductivity from heat extraction in and promising additional...
1D Earth electromagnetic responses to a transient source are shown be greatly dependent on resistivity anisotropy. Isotropic inversion of synthetic data arising from an anisotropic model leads either misleading results (incorrect target depth and poor accuracy in recovered resistivities for background) or non‐convergence. It is that when the correct anisotropy included schemes resulting well resolved. A practical method obtaining starting value through newly defined apparent proposed.
Resistivity anisotropy is shown to have a dominant effect on earth electromagnetic responses. In particular we consider transverse with vertical axis of symmetry and show the effects varying land marine step imp
Joint analysis of seismic and electromagnetic data is difficult because the sets lack a common physical parameter, rock physics usually applied to link two methods via porosity. However, parameters are not well known in near field exploration, estimates likely have large errors associated with them. In this work, we use set relations velocity resistivity. Which relation used function depth lithology, or velocity, itself depth. We then estimate uncertainty our model. apply methodology...
Tracking temperature changes by measuring the resulting resistivity inside low-enthalpy reservoirs is crucial to avoid early thermal breakthroughs and maintain sustainable energy production. The controlled-source electromagnetic method (CSEM) allows for estimation of sub-surface resistivity. However, it has not yet been proven that CSEM can monitor subtle typical reservoirs. In this paper, we present a feasibility study considering monitoring 4–8 Ω·m in deep reservoir model, as part Delft...
Joint analysis of seismic and electromagnetic data is difficult because the sets lack a common physical parameter, rock physics usually applied to link two methods via porosity. However, parameters are not well known in near field exploration, estimates likely have large errors associated with them. In this work, we use Gassmann equation velocity porosity, self-similar model porosity resistivity. We calculate simple depth-trend from data, estimate uncertainty our model. apply methodology...
Summary Modelling time-domain electromagnetic data with a frequency-domain code requires the computation of many frequencies for Fourier transform. This can make it computationally very expensive when compared codes. However, has been shown that codes be competitive if frequency-dependent modelling grids and clever frequency selection are used. We improve existing schemes by focusing on (a) minimizing dimension required grid (b) logarithmically-spaced transforms interpolation. These two...