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open access

Single well seismic imaging of a gas-filled hydrofracture

Description: A single well seismic survey was conducted at the Lost Hills, Ca oil field in a monitoring well as part of a CO2 injection test. The source was a piezoelectric seismic source and the sensors were a string of hydrophones hanging below the source. The survey was processed using standard CMP reflection seismology techniques. A potential reflection event was observed and interpreted as being caused by a near vertical hydrofracture. The radial distance between the survey well and the hydrofracture i… more
Date: August 19, 2003
Creator: Daley, Thomas M.; Gritto, Roland & Majer, Ernest L.
Partner: UNT Libraries Government Documents Department
open access

Subsurface void detection using seismic tomographic imaging

Description: Tomographic imaging has been widely used in scientific and medical fields to remotely image media in a nondestructive way. This paper introduces a spectrum of seismic imaging applications to detect and characterize voids in coal mines. The application of seismic waves to detect changes in coal relies on two types of waves: body waves refracted along the interface between coal and bedrock (i.e., refracted P-waves) and channel waves that propagate directly through the coal (dispersive wave trains… more
Date: June 26, 2003
Creator: Gritto, Roland
Partner: UNT Libraries Government Documents Department
open access

Seismic methods for resource exploration in enhanced geothermal systems

Description: A finite-difference modeling study of seismic wave propagation was conducted to determine how to best investigate subsurface faults and fracture zones in geothermal areas. The numerical model was created based on results from a previous seismic reflection experiment. A suite of fault models was investigated including blind faults and faults with surface expressions. The seismic data suggest that blind faults can be detected by a sudden attenuation of seismic wave amplitudes, as long the fault i… more
Date: June 12, 2002
Creator: Gritto, Roland & Majer, Ernest L.
Partner: UNT Libraries Government Documents Department
open access

Integrated seismic studies at the Rye Patch Geothermal Reservoir, Nevada

Description: A 3-D surface seismic reflection survey, covering an area of over 3 square miles, was conducted at the Rye Patch geothermal reservoir (Nevada) to explore the structural features that may control geothermal production in the area. In addition to the surface sources and receivers, a high-temperature three-component seismometer was deployed in a borehole at a depth of 3900 ft within the basement below the reservoir, which recorded the waves generated by all surface sources. A total of 1959 first-a… more
Date: May 23, 2002
Creator: Gritto, Roland; Daley, Thomas M. & Majer, Ernest L.
Partner: UNT Libraries Government Documents Department
open access

Imaging of CO{sub 2} injection during an enhanced-oil-recovery experiment

Description: A series of time-lapse seismic cross well and single well experiments were conducted in a diatomite reservoir to monitor the injection of CO{sub 2} into a hydrofracture zone, using P- and S-wave data. During the first phase the set of seismic experiments were conducted after the injection of water into the hydrofrac-zone. The set of seismic experiments was repeated after a time period of 7 months during which CO{sub 2} was injected into the hydrofractured zone. The issues to be addressed ranged… more
Date: April 29, 2003
Creator: Gritto, Roland; Daley, Thomas M. & Myer, Larry R.
Partner: UNT Libraries Government Documents Department
open access

Joint Cross Well and Single Well Seismic Studies at Lost Hills, California

Description: A series of time-lapse seismic cross well and single well experiments were conducted in a diatomite reservoir to monitor the injection of CO{sub 2} into a hydrofracture zone, based on P- and S-wave data. A high-frequency piezo-electric P-wave source and an orbital-vibrator S-wave source were used to generate waves that were recorded by hydrophones as well as three-component geophones. The injection well was located about 12 m from the source well. During the pre-injection phase water was inject… more
Date: June 25, 2002
Creator: Gritto, Roland; Daley, Thomas M. & Myer, Larry R.
Partner: UNT Libraries Government Documents Department
open access

Inversion of Scattered Waves for Material Properties in Fractured Rock

Description: The authors apply a recently developed low-frequency, non-linear inversion method which includes near and far field terms to a crosshole data set to determine the bulk and shear modulus, as well as the density for a fractured zone in a granitic rock mass. The method uses the scattered elastic wavefield which is extracted from the recorded data before the inversion is performed. The inversion result is appraised by investigating the resolution and standard deviation of the model estimates. The s… more
Date: July 1999
Creator: Gritto, Roland; Korneev, Valeri A. & Johnson, Lane R.
Partner: UNT Libraries Government Documents Department
open access

Seismic Imaging of UXO-Contaminated Underwater Sites (Interim Report)

Description: Finite difference modeling with 2-dimensional models were conducted to evaluate the performance of source-receiver arrays to locate UXO in littoral environments. The model parameters were taken from measurements in coastal areas with typical bay mud and from examples in the literature. Seismic arrays are well suited to focus energy by steering the elements of the array to any point in the medium that acts as an energy source. This principle also applies to seismic waves that are backscattered b… more
Date: November 30, 2004
Creator: Gritto, Roland; Korneev, Valeri; Nihei, Kurt & Johnson, Lane
Partner: UNT Libraries Government Documents Department
open access

Pressure and fluid saturation prediction in a multicomponent reservoir, using combined seismic and electromagnetic imaging

Description: This paper presents a method for combining seismic and electromagnetic measurements to predict changes in water saturation, pressure, and CO{sub 2} gas/oil ratio in a reservoir undergoing CO{sub 2} flood. Crosswell seismic and electromagnetic data sets taken before and during CO{sub 2} flooding of an oil reservoir are inverted to produce crosswell images of the change in compressional velocity, shear velocity, and electrical conductivity during a CO{sub 2} injection pilot study. A rock properti… more
Date: 2002-10~
Creator: Hoversten, G. M.; Gritto, Roland; Washbourne, John & Daley, Tom
Partner: UNT Libraries Government Documents Department
open access

Crosswell seismic and electromagnetic monitoring of CO2sequestration

Description: The quantitative estimation of changes in water saturation (S{sub W}) and effective pressure (P), in terms of changes in compressional and shear impedance, is becoming routine in the interpretations of time-lapse surface seismic data. However, when the number of reservoir constituents increases to include in situ gas and injected CO{sub 2}, there are too many parameters to be determined from seismic velocities or impedances alone. In such situations, the incorporation of electromagnetic (EM) im… more
Date: July 30, 2002
Creator: Hoversten, G. Michael; Gritto, Roland; Daley, Thomas M.; Majer,Ernest L. & Myer, Larry R.
Partner: UNT Libraries Government Documents Department
open access

CO2 gas/oil ratio prediction in a multi-component reservoir bycombined seismic and electromagnetic imaging

Description: Crosswell seismic and electromagnetic data sets taken before and during CO2 flooding of an oil reservoir are inverted to produce crosswell images of the change in compressional velocity, shear velocity and electrical conductivity during a CO2 injection pilot study. A rock properties model is developed using measured log porosity, fluid saturations, pressure, temperature, bulk density, sonic velocity and electrical conductivity. The parameters of the rock properties model are found by an L1-norm… more
Date: August 28, 2002
Creator: Hoversten, G.M.; Gritto, Roland; Washbourne, John & Daley, Tom
Partner: UNT Libraries Government Documents Department
open access

Workshop on induced Seismicity due to fluid injection/production from Energy-Related Applications

Description: Geothermal energy, carbon sequestration, and enhanced oil and gas recovery have a clear role in U.S. energy policy, both in securing cost-effective energy and reducing atmospheric CO{sub 2} accumulations. Recent publicity surrounding induced seismicity at several geothermal and oil and gas sites points out the need to develop improved standards and practices to avoid issues that may unduly inhibit or stop the above technologies from fulfilling their full potential. It is critical that policy ma… more
Date: April 1, 2011
Creator: Majer, E. L.; Asanuma, Hiroshi; Rueter, Horst; Stump, Brian; Segall, Paul; Zoback, Mark et al.
Partner: UNT Libraries Government Documents Department
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