G. Michael Hoversten

G. Michael Hoversten
Chevron · Earth Science Division

About

147
Publications
38,783
Reads
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2,834
Citations
Additional affiliations
September 1998 - June 2006
Lawrence Berkeley National Laboratory
Position
  • Staff Scientist, Energy Resources Program Head
September 1998 - September 2006
Lawrence Berkeley National Laboratory
Position
  • Staff Scientist, Energy Resources Program Head Lawrence Berkeley National Laboratory
Description
  • Developed industry funded research projects, including marine EM survey design and development of new 3D deterministic and stochastic potential field inversion algorithms.

Publications

Publications (147)
Article
Full-text available
In 2002 and 2003 a collaborative effort was undertaken between Lawrence Berkeley National Laboratory, Sandia National Laboratories, the U.S. Geological Survey (USGS) Menlo Park, the USGS Hawaiian Volcano Observatory, and Electromagnetic Instruments Inc. to study the Kīlauea volcano in Hawaii using the magnetotelluric (MT) technique. The work was mo...
Article
Full-text available
In geophysical inversions, lower and upper model parameter bounds are a means of solution stabilization. Further, constraints that intend to let only geologically plausible inverse solutions pass are amenable to lower and upper bounds. Reliable prior information is paramount to construct such bound constraints. It is common practice to narrow and w...
Article
Full-text available
Seismic tube waves, produced by flexure of the well boundary, pressure changes in the fluid in the well, and deformation of the material immediately surrounding the well, are particularly sensitive to variations in the state of the well. We evaluate a direct approach for generating and observing tube waves as a means of detecting well damage. While...
Article
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Cumulative oil predictions are made from stochastically inverted earth attributes. The inverted attributes are from the SEAM Life of Field model and an offshore field in West Africa. To perform the prediction we use a Naïve Bayesian Classifier for its transparency in methodology, computational efficiency, and flexibility. The inverted properties we...
Article
In the past decade, rapid advances in distributed optical fiber sensing technologies have made it possible to record various geophysical data (e.g., strain, temperature, and pressure) continuously in both time and space along the fiber, providing an unprecedented quantity and spatial density of data compared to traditional geophysical measurements...
Article
In 2010 an exploration well was drilled in the Lona prospect in the Orphan Basin, Canada, whose location was based primarily on a structural high at the base of a Cretaceous unconformity. Additionally, three-dimensional (3D) inversion of controlled-source electromagnetic (CSEM) data collected in 2007 and 2009 indicated elevated resistivities that r...
Article
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We present a new graph-Laplacian based semi-supervised clustering method. This new approach can be viewed as an extension/improvement of previously published work, both in terms of areas of applicability and computational speed. Our clustering method is capable of handling very large datasets with millions of data points using very limited amounts...
Article
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A coupled approach, combining the theory of rate‐ and state‐dependent friction and methods from poroelasticity, forms the basis for a quantitative relationship between displacements and fluid leak‐off from a growing fracture and changes in the rate of seismic events in the region surrounding the fracture. Poroelastic Green's functions link fracture...
Article
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Numerical modeling of a North American hydraulic fracture experiment is done to demonstrate the accuracy with which the volume containing proppant could be estimated when electrically conductive proppant is used. An electromagnetic (EM) acquisition system with surface electric and magnetic field receivers and a grounded electric dipole source is si...
Article
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Efficient and safe production of hydraulically fractured reservoirs benefits from the prediction of their geometrical attributes. Geophysical methods have the potential to provide data that are sensitive to fracture geometries, alleviating the typically sparse nature of in situ reservoir observations. Moreover, surface-based methods can be logistic...
Conference Paper
Full-text available
Article
We present a value of information (VOI) analysis for magnetotelluric (MT) data for locating high steam flow regions of a geothermal resource. The high electrical conductivity feature in volcanic geothermal settings, known as the clay cap, can be indicative of geothermal alteration occurring just above the resource. We demonstrate how several altern...
Article
Observed deformation is sensitive to a changing stress field within the Earth. However, there are several impediments to a direct inversion of geodetic measurements for changes in stress. Estimating six independent components of stress change from a smaller number of displacement or strain components is inherently non-unique. The reliance upon surf...
Article
Full-text available
We present an algorithm to recover the Bayesian posterior model probability density function of subsurface elastic parameters, as required by the full pressure field recorded at an ocean bottom cable due to an impulsive seismic source. Both the data noise and source wavelet are estimated by our algorithm, resulting in robust estimates of subsurface...
Conference Paper
Full-text available
Our numerical proof-of-concept studies demonstrate that surface electric field measurements can provide sensitivity to both the geometric distribution of injected conductive fluids and or conductively enhanced proppant as well as sensitivity to the created hydraulic permeability of the fracture zone. This is the first demonstration of a capability...
Article
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Wells and boreholes are routinely steel-cased in oil and gas fields and geological storage sites. There have been a number of studies on the effects of a steel-cased well on various electrical and electromagnetic (EM) geophysical methods. In this paper, we examine the use of a steel-cased well as a virtual vertical electric source for sensing deep...
Article
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The recent use of marine electromagnetic technology for exploration geophysics has primarily focused on applying the controlled source electromagnetic method for hydrocarbon mapping. However, this technology also has potential for structural mapping applications, particularly when the relative higher frequency controlled source electromagnetic data...
Patent
A system and a computer implemented method for determining a value of information are described herein. The method includes drawing a plurality of synthetic prior earth models from one or more prior distributions for a plurality of well locations and generate from each prior distribution synthetic data; and drawing a plurality of posterior earth mo...
Article
Full-text available
Including highly conductive steel infrastructure into electromagnetic (EM) earth modeling is motivated by the fact that long metal-cased boreholes have the potential to be used as boosting antennas that enable larger source dipole moments and greater signal penetration depths. Unfortunately, geophysical algorithms designed to simulate EM responses...
Patent
Full-text available
A system and a method for estimating a reservoir parameter are provided. The method includes calculating a plurality of priors using a Markov random field, the plurality of priors comprising probability distributions of a plurality of litho-types; calculating posterior distributions based on the priors, the posterior distribution depending upon mea...
Conference Paper
Full-text available
We develop a Bayesian model to invert 2D magnetotelluric (MT) data using a pixel-based parameterization, and apply it to an active geothermal field. Although this parameterization is more flexible in representing subsurface resistivity structure than sharp boundary models, it may cause problems for Markov chain Monte Carlo (MCMC) based Bayesian met...
Article
Full-text available
We present a value of information methodology for the exploration of hidden geothermal resources. Specifically, this methodology is applicable for spatial decisions, such as, "Where to drill?" We evaluate how well the magnetotellurics (MT) technique is able to delineate the lateral position of the low resistive materials that are indicative of a hi...
Article
Full-text available
As motivation for considering new electromagnetic techniques for hydraulic fracture monitoring, we develop a simple financial model for the net present value offered by geophysical characterization to reduce the error in stimulated reservoir volume calculations. This model shows that even a 5% improvement in stimulated reservoir volume for a 1 bill...
Article
Full-text available
Bayesian methods can quantify the model uncertainty that is inherent in inversion of highly nonlinear geophysical problems. In this approach, a model likelihood function based on knowledge of the data noise statistics is used to sample the posterior model distribution, which conveys information on the resolvability of the model parameters. Because...
Conference Paper
Full-text available
Accurately estimating low frequency trends in seismic attributes is very important for seismic imaging and full waveform inversion. In this study, we develop a sequential Bayesian model to invert elastic seismic data in the frequency-ray parameter domain for recovering the low frequency components of geophysical parameters. We first transform time-...
Conference Paper
A modeling study has been undertaken to investigate the resolution and accuracy of marine magnetotelluric (MT) and controlled source electromagnetic (CSEM) data to image the base of basalt and sediments in an environment representative of the North Atlantic Margin. The three dimensional (3D) model was constructed using regional well logs, seismic a...
Article
Full-text available
Seismic imaging for hydrocarbon beneath basalt is often challenging due to the high velocity and extreme heterogeneity of basalt flows. When assessing the prospectivity beneath basalt, a critical factor is the presence of sediments within a depth range that will accommodate hydrocarbons. If sediments are present, the depth extent and structure of t...
Article
Effective‐medium theories for either highly conductive or more resistive electrical inclusions in a moderately conducting background medium are presented for modelling macroscopic (i.e., large‐scale) fluid‐filled fractures or cracks in a potential reservoir rock or granular medium. Conductive fluids are most often brine and the resistive fluids of...
Article
Full-text available
We developed a Bayesian model to invert magnetotelluric (MT) data using a 2D sharp boundary parameterization. We divided the 2D cross section into layers and considered the locations of interfaces and resistivity of the regions formed by the interfaces as random variables. We assumed that those variables are independent in the vertical direction an...
Article
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Geophysical and hydrogeological inverse problems often include a large number of unknown parameters, ranging from hundreds to millions, depending on parameterization and problems undertaking. This makes inverse estimation and uncertainty quantification very challenging, especially for those problems in two- or three-dimensional spatial domains. Mod...
Article
Full-text available
Traditional deterministic geophysical inversion algorithms are not designed to provide a robust evaluation of uncertainty that reflects the limitations of the geophysical technique. Stochastic inversions, which do provide a sampling-based measure of uncertainty, are computationally expensive and not straightforward to implement for nonexperts (nons...
Article
Full-text available
Joint inversion of seismic AVA and CSEM data requires rock-physics relationships to link seismic attributes to electrical properties. Ideally, we can connect them through reservoir parameters (e.g., porosity and water saturation) by developing physical-based models, such as Gassmann’s equations and Archie’s law, using nearby borehole logs. This cou...
Article
Full-text available
We introduce a new numerical method to simulate geophysical marine controlled source electromagnetic (CSEM) measurements for the case of 2D structures and finite 3D sources of electromagnetic (EM) excitation. The method of solution is based on a spatial discretization that combines a 1D Fourier transform with a 2D self-adaptive, goal-oriented, hp-F...
Article
Deepwater gas exploration is challenging and subject to a large degree of uncertainty. Seismic imaging techniques, such as seismic amplitude versus angles (AVA), can provide good information about the physical location and porosity of potential gas-bearing sands, but they cannot discriminate between economic and non-economic gas concentrations beca...
Conference Paper
Full-text available
Stochastic approaches for inverting geophysical data have many advantages over deterministic inversion methods in terms of finding global solutions and quantifying their associated uncertainty. Since stochastic methods often need to run forward models more times than deterministic algorithms, their applications currently are limited to 1D inverse p...
Conference Paper
Full-text available
An extensive magnetotelluric (MT) survey comprised of 85 sites has been acquired over the Darajat geothermal field in Indonesia to map the geothermal reservoir and the overlying clay cap. The rouged topography and the geometry of the margin of the clay cap makes the resistivity structure 3D at reservoir depth. Although 3D MT inversion is now common...
Conference Paper
Full-text available
Joint inversion of seismic AVA and CSEM data needs rock-physics models to link seismic attributes to electrical properties. Ideally, we can develop physical-based models (e.g., Gassmann's equation and Archie's law) from nearby borehole logs to connect them through reservoir parameters (e.g., porosity and water saturation). However, in the explorati...
Conference Paper
Full-text available
The work presented here describes the motivation and challenges of implementing CPU expensive stochastic inversions for two electromagnetic geophysical techniques: magnetotellurics and controlled-source EM. Examples of implementation and convergence criteria in the geophysical literature are limited, making it difficult for non-experts (non-statist...
Article
Full-text available
This report summarizes the work performed between January 2005 and December 2007, under DOE research contract DE-FC26-04NT15507. The project is was performed by the Center for Petroleum and Geosystems Engineering of The University of Texas at Austin and Lawrence Berkeley National Laboratory under the auspices of the National Energy Technology Offic...
Article
Full-text available
Sequestration/enhanced oil recovery (EOR) petroleum reservoirs have relatively thin injection intervals with multiple fluid components (oil, hydrocarbon gas, brine, and carbon dioxide, or CO(2)), whereas brine formations usually have much thicker injection intervals and only two components (brine and CO(2)). Coal formations undergoing methane extra...
Article
Full-text available
A dense grid of 125 magnetotelluric (MT) stations plus a single line of contiguous bipole array profiling has been acquired over the east flank of the Coso geothermal system, CA, USA. Due to production related electromagnetic (EM) noise the permanent observatory at Parkfield, CA was used as a remote reference to suppress this cultural EM noise inte...
Conference Paper
Full-text available
Single-well seismic methods have been used for environmental investigations and natural resources exploration as cost-effective approaches for subsurface imaging. Current modeling studies primarily focus on numerical simulation of the governing elastic wave equations. In this study, we develop a Bayesian inversion method to estimate elastic paramet...
Article
Full-text available
Seismic surveys successfully imaged a small scale CO2 injection (1,600ton) conducted in a brine aquifer of the Frio Formation near Houston, Texas. These time-lapse borehole seismic surveys, crosswell and vertical seismic profile (VSP), were acquired to monitor the CO2 distribution using two boreholes (the new injection well and a pre-existing well...
Article
We have carried out an investigation of the Coso Geothermal field utilizing a dense grid of magnetotelluric (MT) stations plus a single line of contiguous bipole array profiling over the east flank of the field. Motivation for this study is that electrical resistivity/conductivity mapping can contribute to better understanding of enhanced geotherma...
Article
We present a split-step complex Padé-Fourier migration method based on the one-way wave equation. The downward-continuation operator is split into two downward-continuation operators: one operator is a phase-shift operator and the other operator is a finite-difference operator. A complex treatment of the propagation operator is applied to mitigate...
Conference Paper
Full-text available
Reliable estimates of gas saturation need to combine the commonly used seismic imaging techniques with the recently developed controlled-source electromagnetic (CSEM) methods. However, conventional methods for inversion of seismic and CSEM data are limited because such methods depends on the choice of the initial model parameters and cannot provide...
Article
Full-text available
We develop a Bayesian model to jointly invert marine seismic amplitude versus angle (AVA) and controlled-source electromagnetic (CSEM) data for a layered reservoir model. We consider the porosity and fluid saturation of each layer in the reservoir, the bulk and shear moduli and density of each layer not in the reservoir, and the electrical conducti...
Article
Electrical resistivity may contribute to progress inunderstanding geothermal systems by imaging the geometry, bounds andcontrolling structures in existing production, and thereby perhapssuggesting new areas for field expansion. To these ends, a dense grid ofmagnetotelluric (MT) stations plus a single line of contiguous bipolearray profiling has bee...
Article
Full-text available
Because of their wide application within the petroleum industry, it is natural to consider geophysical techniques for monitoring of CO2 movement within hydrocarbon reservoirs, whether the CO2 is introduced for enhanced oil/gas recovery or for geologic sequestration. Among the available approaches to monitoring, seismic methods are by far the most h...
Article
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Analysis of a current offshore prospect employed 3D numerical modeling of a control led-source electromagnetic (CSEM) exploration system. The analysis considers the sensitivity of data presentations to assumptions about the background model. The numerical simulations show that false anomalies and significant distortion to anomaly magnitude can be c...
Article
From FY 2000 through FY 2003, a series of vadose zone transport field experiments were conducted as part of the U.S. Department of Energy’s Groundwater/Vadose Zone Integration Project Science and Technology Project, now known as the Remediation and Closure Science Project, and managed by the Pacific Northwest National Laboratory (PNNL). The series...
Article
Full-text available
A stochastic joint-inversion approach for estimating reser-voir-fluid saturations and porosity is proposed. The approach couples seismic amplitude variation with angle AVA and marine controlled-source electromagnetic CSEM forward models into a Bayesian framework, which allows for integra-tion of complementary information. To obtain minimally subjec...
Article
Full-text available
Sedimentary rocks beneath the Columbia River Basalt Group are recognized as having potential for oil and gas production, but the overlying layered basalts effectively mask seismic reflections from the underlying sediments. Four electromagnetic (EM) methods have been applied on profiles crossing Boylston Ridge, a typical east–west trending anticline...
Article
Full-text available
Hydrocarbon exploration in the Papuan fold belt is made extremely difficult by mountainous terrain, equatorial jungle and thick karstified Miocene limestones at the surface. The high‐velocity karstified limestones at or near the surface often render the seismic technique useless for imaging the subsurface. In such areas magnetotellurics (MT) provid...
Article
Full-text available
In 2006, the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) plans to undertake (subject to receiving the necessary approvals) a Pilot program for CO2 storage within a depleted gas reservoir. The Otway Basin Pilot Program (OBPP) aims to demonstrate that subsurface CO2 storage is both economically and environmentally sustainable...
Article
We present a Fourier finite-difference common azimuth depth migration method. Like the Fourier finite-difference (FFD) method, the exact operator for the downward continuation is split into three operators: a phase-shift operator, the first-order correction term of the split-step Fourier migration method and the new finite-difference term. It can p...
Article
We present two-dimensional forward and inversion algorithms for the interpretation of marine controlled-source electromagnetic data. The forward algorithm employs a staggered-grid finite difference solution to the total-electricfield Helmholtz equation. Quick solution times are achieved through a) an optimal grid technique that extends the boundari...
Article
The use of controlled source electromagnetics (CSEM) in the marine environment has grown rapidly in the past few years from a simple anomaly hunting technique used in geologically simple environments to a modeling and inversion based technique applied in structurally and lithologically complex environments. The tool set most commonly available to i...
Article
The use of controlled source electromagnetics (CSEM) in the marine environment has grown rapidly in the past few years from a simple anomaly fluid-hunting technique used in geologically simple environments to a modeling and inversion based technique applied in structurally and lithologically complex environments (Carazzone et al., 2005). The tool s...