Lewis Bartel

Lewis Bartel

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84
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664
Citations

Publications

Publications (84)
Article
Long term geologic sequestration of carbon dioxide (CO2) is considered a viable approach for removing large amounts of excess carbon from the earth's surface environment. As CO2 is injected into a subsurface porous formation, it displaces (or mixes with) in situ pore fluids. Seismic reflection and transmission responses of the formation depend on t...
Article
Full-waveform seismic reflection responses of an isolated porous sandstone layer are simulated with three-dimensional (3D) isotropic poroelastic and isotropic elastic finite-difference (FD) numerical algorithms. When the pore-filling fluid is brine water with realistic viscosity, there is about a ∼10% difference in synthetic seismograms observed in...
Article
Sequestration of CO2 in depleted oil reservoirs, saline aquifers, or unminable coal sequences may prove to be an economical and environmentally safe means for long-term removal of carbon from the atmosphere. Requirements for storage of CO2 in subsurface geologic repositories (e.g., less than 0.1% per year leakage) pose significant challenges for ge...
Article
We present a technique that allows for the simultaneous acquisition and interpretation of both shear-wave and compressive-wave 3-D velocities. The technique requires no special seismic sources or array geometries, and is suited to studies with small source-receiver offsets. The method also effectively deals with unwanted seismic arrivals by using t...
Article
Average shear-wave velocity in the upper 30 meters is a key parameter for seismic hazard calculations. Geologic maps show poor correlation with predicted subsurface velocity, therefore measurements are needed at multiple locations for the area of interest. We present an alternative to existing surface-wave techniques (e.g. SASW, MASW, ReMi) for rap...
Article
Summary With the purpose of attaching meaning to the waveforms imaged by reverse-time migration, we obtain an expression for the output of such an algorithm over a simple subsurface model of a dipping interface. We invoke the cross-correlation imaging condition and make extensive use of the stationary phase approximation to analyze the migrated ima...
Article
Three-dimensional seismic wave propagation within a heterogeneous, isotropic poroelastic medium is simulated with an explicit, time-domain, finite-difference algorithm. A system of thirteen, coupled, first-order partial differential equations is solved for the velocity vector components, stress tensor components, and pressure associated with solid...
Article
We present a method to improve the automatic arrival-time picking of small source-receiver-offset surface waves. We use very narrow bandpass filters and the Hilbert transform to find the instantaneous amplitude at discrete frequencies. We then make the assumption that the maximum instantaneous amplitude of the waveform represents the fundamental mo...
Conference Paper
The air/earth interface is accurately represented in a 3D finite-difference elastic wave propagation algorithm merely by assigning material properties of air to the spatial grid nodes above the earth's surface. Computational stability is maintained by making the boundary gradational. Synthetic seismic traces calculated by this approach compare favo...
Article
A method for monitoring an enhanced oil recovery (EOR) process is the mapping of electrical conductivity changes due to injection of steam or other fluids. Since the conductivity change will be three-dimensional (3-D) in character, it is necessary to develop techniques to map 3-D conductivity distributions. At the Richmond test site, near Berkeley...
Article
The multifrequency, multisource holographic method used in the analysis of seismic data is to extended electromagnetic (EM) data within the audio frequency range. The method is applied to the secondary magnetic fields produced by a borehole, vertical electric source (VES). The holographic method is a numerical reconstruction procedure based on the...
Article
For the central-loop induction TEM (transient electromagnetic) method, the effects of surface conductors on the late-time apparent resistivity are investigated. These conductors can be pipelines, power lines, railroad tracks, fences, brine ponds, etc. In this paper, two cases are investigated through numerical simulations: a long, linear conductor...
Article
Mapping and monitoring of enhanced oil recovery processes are important to predict process behavior and to be able to control the process for maximizing oil recovery. If there are electrical resistivity contrasts between various phases of a process, then electrical and/or electromagnetic geophysical techniques may be useful to map and monitor the p...
Article
An improved capability for subsurface structure detection is needed to support military and non‐proliferation requirements for inspection and for surveillance of activities of threatening nations. As part of the U.S. Department of Energy program to apply geophysical methods to detect and characterize underground facilities, Sandia National Laborato...
Article
Borehole-to-surface electromagnetic (EM) methods are an attractive alternative to Surface-based EM methods for a variety of environmental and engineering applications. They have improved sensitivity to the subsurface resistivity distribution because of the closer proximity to the area of interest offered by the borehole for the source or the receiv...
Article
In our reply to the discussion by Szarka (this issue), we examined the near‐field correction scheme for two‐layer cases with a basal layer more conducting and less conducting than the surface layer where we only considered the broadside configuration. Maurer points out that for the collinear configuration the correction scheme does not produce an a...
Article
A continuously cored hole penetrated 715 m into the southwestern moat of the Long Valley caldera. Temperatures in the postcaldera deposits increased rapidly with depth over the upper 335 m to 202°C, then remained nearly isothermal into the Bishop Tuff to the bottom of the hole. The depth to the Bishop Tuff is the shallowest, and the temperatures ob...
Article
In February of 1984, the authors performed a controlled-source audiofrequency magnetotelluric (CSAMT) electromagnetic geophysical survey at the Puhimau thermal area to investigate the electrical nature of the thermal anomaly and estimate the depth to any hot water and/or remaining molten magma. A technique was developed to correct near-field CSAMT...
Article
On June 17, 1986, a continuously cored hole was completed in Long Valley Caldera, approximately 2 km northeast of the town of Mammoth Lakes, Calif. The primary purpose of the hole is to provide access for periodic measurement of the thermal gradient, pressure, and chemistry of water in the thermal aquifer of the caldera's southwestern moat. The hol...
Article
The controlled source audio-frequency magnetotelluric (CSAMT) surface electromagnetic geophysical technique was used to monitor the Tono project partial seam CRIP UCG (controlled retracting injection point underground gasification) test conducted on the WIDCO mine property near Centralia, Washington. The results of the monitoring show a changing re...
Article
During the recent 1983 eruption of Kilauea Volcano in Hawaii, a field measurement of electrical resistivity was made in an 1118°C molten lava flow. A probe containing a four electrode. Wenner aray was inserted into the molten basaltic lava flow at a point about 100 m from the erupting vent. The probe indicated an electrical resistivity of approxima...
Article
The mapping of enhanced oil recovery (EOR) processes is important to predict process behavior and to be able to exhibit some process behavior and to be able to exhibit some control of the process for maximizing the stimulation of oil reservoirs. The controlled source audio-frequency magnetotelluric (CSAMT) electromagnetic geophysical technique show...
Article
Use of electromagnetic geophysical prospecting techniques to map EOR processes depends upon prospecting techniques to map EOR processes depends upon electrical resistivity changes of the affected region. Sandia is evaluating the use of the controlled source audio-frequency magnetotelluric (CSAMT) electromagnetic geophysical prospecting technique to...
Article
Seven instrumentation techniques were designed, fielded, and evaluated on the Hanna II in situ coal gasification experiment conducted in 1975-76. Diagnostic techniques (thermal, inseam gas sampling and pressure, and overburden tilt and displacement) were used to obtain data for process characterization. Remote monitoring techniques (electrical, pas...
Article
Two electrical techniques for monitoring an in situ coal gasification process from the surface were evaluated on the Hanna II experiment conducted by the Laramie Energy Research Center. The basis for these techniques is that hot, carbonized coal in the reaction zone is conductive and thus can distort an applied current or serve as part of the curre...
Article
The Hanna II in-situ coal gasification experiment was conducted by the Laramie Energy Research Center during 1975 to 76. Sandia Laboratories designed, fielded, and evaluated variations of seven instrumentation techniques belonging to two general classes: (a) diagnostic techniques (thermal, in-seam gas sampling and pressure, and overburden tilt and...
Article
Three massive hydraulic fracture experiments for natural gas stimulation were conducted on three wells. All three wells were open hole and the fracture zone was located at a depth of approximately 8000 ft. All were treated with approximately 300,000 gal of fluid and 600,000 lb of proppant. The surface electrical potential technique was used to atte...
Article
American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Abstract Mapping of massive hydraulic fractures allows for their efficient use to stimulate natural gas production in tight formations. A mapping technique has been used by Sandia Laboratories in conjunction with industry in the Green River Basin at Pinedale, Wyoming and in...
Conference Paper
Electrical resistivity, passive acoustic, and thermal measurements were made during Phase 1 of the Hanna II in-situ coal gasification experiment. The resistivity and acoustic techniques are under investigation for remote monitoring; the thermal measurements provide diagnostic information and the correlation to the process. Presented are: (1) the mo...
Article
Electrical resistivity and passive acoustic techniques have been used to remotely monitor the location of the reaction zone in an in situ coal gasification experiment conducted near Hanna, Wyoming. Thermal measurements were made to provide diagnostic information, to aid in provide diagnostic information, to aid in understanding the process, and to...
Article
Resonance broadening is included along with spin‐disorder scattering to study the magnetic properties of the Hubbard Hamiltonian in the weak correlation limit. The calculated susceptibility is compared to the exchange enhanced Hartree–Fock approximation (HFA) susceptibility, and limits are set on the applicability of the HFA. For a semicircular den...
Article
This theoretical and experimental investigation deals with the electromechanical response of a shock-loaded ferroelectric ceramic material. Quartz gauge and voltage-mode techniques were used to characterize the mechanical and electrical responses, respectively, of PZT 65/35 to ≈80 kbar. Below ≈20 kbar the wave propagation was dispersive, whereas st...
Article
The magnetization, Curie temperature, and pressure dependence of the Curie temperature have been measured for the Fe0.65(Ni1−xCox)0.35 alloy system, where 0≤x≤0.08. The magnetization and Curie temperature were observed to be nearly independent of Co concentration, while the pressure derivative of the Curie temperature was found to increase in magni...
Article
In this paper, resonance broadening is included along with spin-disorder scattering to study the properties of the Hubbard Hamiltonian. Our solution, obtained through use of the locator technique, is valid for all strengths of the Coulomb repulsion term and for all band occupancies. However, here we restrict our work to the strong-correlation limit...
Article
In this paper the resonance-broadening terms are included along with the spin-disorder scattering term to study the zero temperature magnetic properties of the Hubbard model Hamiltonian and to compare results with those using the coherent potential approximation (CPA). Although our solution is valid for all strengths of the Coulomb repulsion term,...
Article
The transverse dynamic susceptibility for the modified Zener model of ferromagnetism is calculated in order to examine the behavior of neutron scattering resonances at low temperatures and at the Curie temperature TC. The relationship of these calculations to those for a pure itinerant-electron ferromagnet is discussed. The inadequacy of the random...
Article
An essential feature of the modified Zener model for ferromagnetism in transition metals and alloys is the coupling of an itinerant d electron to a localized spin in accordance with Hund's rule. In contrast to the Stoner-Wohlfarth model for ferromagnetism, this model takes into account the Hund's-rule effects and the orbital degeneracy of the d ele...
Article
In the model, the intra-atomic exchange interaction between the itinerant d electrons and the Hund's rule coupling of the itinerant d electrons to the localized d electrons of spin S produce an exchange splitting, and the ferromagnetism is dominated by the itinerant d electrons. Model calculations of the inverse paramagnetic susceptibility chi-1 ar...
Article
Using Green's function techniques, the limits of stability for f.c.c. type-2 antiferromagnetic order have been calculated where a ferromagnetic, as well as an antiferromagnetic, nearest-neighbor exchange interaction has been allowed. Calculations of exchange constants from susceptibility data are discussed with application to MnO, α-MnS, NiO, GdP a...
Article
A macroscopic Hamiltonian is used to describe and calculate the deviations from saturation and phase changes of the magnetization in a ferromagnet with a uniaxial magnetic anisotropy either parallel or perpendicular to an applied magnetic field. Using Green's-function techniques, we have solved for the component (time, spatially, and thermally aver...
Article
Using an itinerant model for ferromagnetism, we have analyzed the experimental results for the pressure (P) dependence of the Curie temperature (Tc) using present and previously reported data for MnSb and present high pressure results for the Fe. 65(Ni1-xMnx).35 Invars with 0 <= × <= 0.19. Striking agreement between theory and experiment is obtaine...
Article
The ferromagnetic transition temperatures of MnAsxSb1-x solid solutions for 0≤x≤1 have been measured as a function of pressure up to 4.5 kbar. Previous work has shown that for the solid solutions in the concentration range 0.9≲x≤1 the magnetic transition is first order and is accompanied by a hexagonal-to-orthorhombic structure transformation, whil...
Article
A first‐order macroscopic spin‐wave Hamiltonian is used to describe and calculate the deviation of the magnetization from saturation for materials with a uniaxial magnetic anisotropy perpendicular to an applied magnetic field. The calculations predict a spin‐wave deviation from saturation prior to the onset of any actual rotation of the magnetizati...
Article
The ratio of I/Ib, where I and Ib, respectively, are the effective and bare interactions between the itinerant electrons, was estimated on the basis of high pressure and related experiments to be generally greater than 1/2 for Ni3Ga, Ni-Rh, Invar and ZrZn2, indicating weak correlation effects for these materials.
Article
Exchange-striction effects have been studied in both the antiferromagnetic and paramagnetic states of NiO. Near-neighbor spin correlation functions as functions of temperature for various choices of J2/J1 have been calculated using Green's-function techniques and have been compared with our experimental x-ray data measured between 6 and 698°K. The...
Article
In this paper the magnetic contribution to the isotropic lattice contraction in an itinerant antiferromagnet, described by the Hubbard model, is discussed. The isotropic lattice contraction is assumed to arise from the electron‐lattice interaction. The spin polarization per site and the isotropic lattice contraction are calculated for a single half...
Article
Taking into account the exchange-striction effects, the near-neighbor spin correlation functions of MnO are calculated for temperatures below the Néel temperature by using Green's-function techniques with a random-phase Tyablikov decoupling approximation. The resulting theoretical calculations are compared to some experimental results, and it is co...
Article
Full-text available
An improved capability for subsurface structure detection is needed to support military and non-proliferation requirements for inspection and for surveillance of activities of threatening nations. As part of the DOE/NN-20 program to apply geophysical methods to detect and characterize underground facilities, Sandia National Laboratories (SNL) initi...
Article
The controlled source audio-frequency magnetotelluric (CSAMT) technique will be used to monitor an underground-coal-gasification (UCG) experiment. The UCG experiment will be conducted in late summer of 1983 at the Washington Irrigation and Development Co. (WIDCO) property near Centralia, WA. Previous field experiments, mapping the Hanna II, Phases...
Article
Sandia National Laboratories contiued to assist the Laramie Energy Technology Center Tar Sands Program in the areas of reservoir access and alternate extraction concepts. This report covers the work done during the first quarter of FY80 in the areas of controlled source audio magnetotelluric mapping, steam quality sampling hardware, and tar sands d...
Article
Research and development efforts in support of the DOE Heavy Oil RD and D Program in reservoir access were initiated. Preliminary activities in the survey of sand control, drilling, and fracturing techniques in heavy oil formations are described. The continued development of a high temperature packer for use in steam injection applications is prese...
Article
The West Pearl Queen is a depleted oil reservoir that has produced approximately 250,000 bbl of oil since 1984. Production had slowed prior to CO injection, but no previous secondary or tertiary recovery methods had been applied. The initial project involved reservoir characterization and field response to injection of CO; the field experiment cons...
Article
In many parts of the United States, as well as other regions of the world, competing demands for fresh water or water suitable for desalination are outstripping sustainable supplies. In these areas, new water supplies are necessary to sustain economic development and agricultural uses, as well as support expanding populations, particularly in the S...
Article
Sandia National Laboratories has the responsibility for assisting the Laramie Energy Technology Center's Tar Sands Program in the areas of reservoir access and alternate extraction concepts. Activities in the first area have concentrated on high-temperature packers, insulated injection string installation, steam quality measurements, sand control,...
Article
The Sandia National Laboratories Heavy Oil Program is concerned with reservoir access, as defined in the Department of Energy Heavy Oil Program Plan. The program is divided into two major areas: (1) drilling technology and (2) well completions, physical stimulations, and downhole steam production.
Article
The Bartlesville Energy Technology Center (BETC) in situ combustion pilot project near Bartlette, Kansas, was studied using controlled source audio-magnetotelluric (CSAMT) mapping, thermal gravimetric analysis (TGA), conventional geophysical logging and modeling of the fireflood. Measurements of formation resistivity changes induced by in situ comb...
Article
Sandia Laboratories is developing electrical and seismic-acoustic remote monitoring techniques to detect and map underground coal gasification. The electrical methods being evaluated are a modified Schlumberger technique and a dynamic misse-a-la-masse technique and the seismic-acoustic methods being evaluated are an induced seismic transmission and...
Article
The FY'76 major objectives of the Massive Hydraulic Fracture Mapping and Characterization Program were to assess the feasibility of the surface electrical potential and surface seismic systems to provide locational information on hydraulically created fracture systems. The surface electrical potential system has demonstrated the capability to provi...
Article
The need for a reliable, fast, wireless telemetry system in the drilling industry is great but the technical challenge to develop such a system is huge. A downhole wireless telemetry system based on Surface Area Modulation (SAM) has been developed which involves the introduction of an electrically insulated gap near the bottom of an otherwise condu...
Article
In attempting to detect and map out underground facilities, whether they be large-scale hardened deeply-buried targets (HDBT's) or small-scale tunnels for clandestine border or perimeter crossing, seismic imaging using reflections from the tunnel interface has been seen as one of the better ways to both detect and delineate tunnels from the surface...
Article
This project was conducted in the State of Washington to select and characterize a site (or sites) suitable for an underground coal gasification (UCG) experiment. A set of general criteria, based on previous UCG experience, was used to screen potential sites. Based on these criteria, the Tono Basin in the Centralia-Chehalis coal district, was selec...
Article
Mapping and monitoring of enhanced oil recovery processes are important to predict process behavior and to be able to control the process for maximizing oil recovery. If there are electrical resistivity contrasts between various phases of a process, then electrical and/or electromagnetic geophysical techniques may be useful to map and monitor the p...
Article
Full-text available
The strain‐induced uniaxial magnetic anisotropy can cause a deviation in the magnetization from saturation along the applied magnetic field. An approximate variational solution is found for the necessary threshold strain or stress and for the amplitude of this deviation in thick, semi‐infinite slabs of cubic polycrystalline ferro‐ or ferrimagnetic...
Article
A model of the coupled spin-phonon system in solid orthohydrogen at very low temperatures is given. This model is solved exactly. The results are found to be in qualitative agreement with experiment. Si dà un modello del sistema accoppiato spin-fonone nell’ortoidrogeno solido a temperature molto basse. Si risolve esattamente il modello. Si trova ch...
Article
A theory for strain‐induced magnetic anisotropy energy in cubic single‐domain single‐crystal materials based on the usual magnetoelastic coupling model is given in this paper. The application of uniaxial strain such as produced by shock‐wave loading induces an anisotropy field which can rotate the magnetization vector. Calculations based on the the...
Article
The pressure derivatives of the Curie temperature, Tc, have been measured for fcc alloys of Fe with 25-40 at. % Ni, Pd and Pt. A smooth decrease of -(∂Tc/∂P) with increasing Tc is observed for the alloys.

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