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34 results on '"Hoversten, G. Michael"'

15. 3D Magnetotelluic characterization of the Coso Geothermal Field

Author

Newman, Gregory A., Newman, Gregory A., Hoversten, G. Michael, Wannamaker, Philip E., Gasperikova, Erika, Newman, Gregory A., Newman, Gregory A., Hoversten, G. Michael, Wannamaker, Philip E., and Gasperikova, Erika

Abstract

Electrical resistivity may contribute to progress in understanding geothermal systems by imaging the geometry, bounds and controlling structures in existing production, and thereby perhaps suggesting new areas for field expansion. To these ends, a dense grid of magnetotelluric (MT) stations plus a single line of contiguous bipole array profiling has been acquired over the east flank of the Coso geothermal system. Acquiring good quality MT data in producing geothermal systems is a challenge due to production related electromagnetic (EM) noise and, in the case of Coso, due to proximity of a regional DC intertie power transmission line. To achieve good results, a remote reference completely outside the influence of the dominant source of EM noise must be established. Experimental results so far indicate that emplacing a reference site in Amargosa Valley, NV, 65 miles from the DC intertie, is still insufficient for noise cancellation much of the time. Even though the DC line EM fields are planar at this distance, they remain coherent with the nonplanar fields in the Coso area hence remote referencing produces incorrect responses. We have successfully unwrapped and applied MT times series from the permanent observatory at Parkfield, CA, and these appear adequate to suppress the interference of the cultural EM noise. The efficacy of this observatory is confirmed by comparison to stations taken using an ultra-distant reference site east of Socorro, NM. Operation of the latter reference was successful by using fast ftp internet communication between Coso Junction and the New Mexico Institute of Mining and Technology, using the University of Utah site as intermediary, and allowed referencing within a few hours of data downloading at Coso. A grid of 102 MT stations was acquired over the Coso geothermal area in 2003 and an additional 23 stations were acquired to augment coverage in the southern flank of the first survey area in 2005. These data have been inverted to a fully th

Published
2008

16. 3D Magnetotelluic characterization of the Coso Geothermal Field

Author

Newman, Gregory A., Newman, Gregory A., Hoversten, G. Michael, Wannamaker, Philip E., Gasperikova, Erika, Newman, Gregory A., Newman, Gregory A., Hoversten, G. Michael, Wannamaker, Philip E., and Gasperikova, Erika

Abstract

Electrical resistivity may contribute to progress in understanding geothermal systems by imaging the geometry, bounds and controlling structures in existing production, and thereby perhaps suggesting new areas for field expansion. To these ends, a dense grid of magnetotelluric (MT) stations plus a single line of contiguous bipole array profiling has been acquired over the east flank of the Coso geothermal system. Acquiring good quality MT data in producing geothermal systems is a challenge due to production related electromagnetic (EM) noise and, in the case of Coso, due to proximity of a regional DC intertie power transmission line. To achieve good results, a remote reference completely outside the influence of the dominant source of EM noise must be established. Experimental results so far indicate that emplacing a reference site in Amargosa Valley, NV, 65 miles from the DC intertie, is still insufficient for noise cancellation much of the time. Even though the DC line EM fields are planar at this distance, they remain coherent with the nonplanar fields in the Coso area hence remote referencing produces incorrect responses. We have successfully unwrapped and applied MT times series from the permanent observatory at Parkfield, CA, and these appear adequate to suppress the interference of the cultural EM noise. The efficacy of this observatory is confirmed by comparison to stations taken using an ultra-distant reference site east of Socorro, NM. Operation of the latter reference was successful by using fast ftp internet communication between Coso Junction and the New Mexico Institute of Mining and Technology, using the University of Utah site as intermediary, and allowed referencing within a few hours of data downloading at Coso. A grid of 102 MT stations was acquired over the Coso geothermal area in 2003 and an additional 23 stations were acquired to augment coverage in the southern flank of the first survey area in 2005. These data have been inverted to a fully th

Published
2008

17. A Feasibility Study of Non-Seismic Geophysical Methods for Monitoring Geologic CO2 Sequestration

Author

Gasperikova, Erika, Gasperikova, Erika, Hoversten, G. Michael, Gasperikova, Erika, Gasperikova, Erika, and Hoversten, G. Michael

Abstract

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 highly developed and applied. Due to cost considerations, less expensive techniques have recently been considered. In this article, the relative merits of gravity and electromagnetic (EM) methods as monitoring tools for geological CO2 sequestration are examined for two synthetic modeling scenarios. The first scenario represents combined CO2 enhanced oil recovery (EOR) and sequestration in a producing oil field, the Schrader Bluff field on the north slope of Alaska, USA. The second scenario is a simplified model of a brine formation at a depth of 1,900 m.

Published
2006

18. A Feasibility Study of Non-Seismic Geophysical Methods for Monitoring Geologic CO2 Sequestration

Author

Gasperikova, Erika, Gasperikova, Erika, Hoversten, G. Michael, Gasperikova, Erika, Gasperikova, Erika, and Hoversten, G. Michael

Abstract

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 highly developed and applied. Due to cost considerations, less expensive techniques have recently been considered. In this article, the relative merits of gravity and electromagnetic (EM) methods as monitoring tools for geological CO2 sequestration are examined for two synthetic modeling scenarios. The first scenario represents combined CO2 enhanced oil recovery (EOR) and sequestration in a producing oil field, the Schrader Bluff field on the north slope of Alaska, USA. The second scenario is a simplified model of a brine formation at a depth of 1,900 m.

Published
2006

20. An Acoustic Wave Equation for Tilted Transversely Isotropic Media

Author

Zhang, Linbin, Zhang, Linbin, Rector III, James W., Hoversten, G. Michael, Zhang, Linbin, Zhang, Linbin, Rector III, James W., and Hoversten, G. Michael

Abstract

A finite-difference method for computing the first arrival traveltimes by solving the Eikonal equation in the celerity domain has been developed. This algorithm incorporates the head and diffraction wave. We also adapt a fast sweeping method, which is extremely simple to implement in any number of dimensions, to obtain accurate first arrival times in complex velocity models. The method, which is stable and computationally efficient, can handle instabilities due to caustics and provide head waves traveltimes. Numerical examples demonstrate that the celerity-domain Eikonal solver provides accurate first arrival traveltimes. This new method is three times accurate more than the 2nd-order fast marching method in a linear velocity model with the same spacing.

Published
2005

22. An Acoustic Wave Equation for Tilted Transversely Isotropic Media

Author

Zhang, Linbin, Zhang, Linbin, Rector III, James W., Hoversten, G. Michael, Zhang, Linbin, Zhang, Linbin, Rector III, James W., and Hoversten, G. Michael

Abstract

A finite-difference method for computing the first arrival traveltimes by solving the Eikonal equation in the celerity domain has been developed. This algorithm incorporates the head and diffraction wave. We also adapt a fast sweeping method, which is extremely simple to implement in any number of dimensions, to obtain accurate first arrival times in complex velocity models. The method, which is stable and computationally efficient, can handle instabilities due to caustics and provide head waves traveltimes. Numerical examples demonstrate that the celerity-domain Eikonal solver provides accurate first arrival traveltimes. This new method is three times accurate more than the 2nd-order fast marching method in a linear velocity model with the same spacing.

Published
2005

27. The GEO-SEQ project: A status report

Author

Myer, Larry R., Myer, Larry R., Benson, Sally M., Byrer, Charles, Cole, David, Doughty, Christine A., Gunter, William, Hoversten, G. Michael, Hovorka, Susan, Johnson, James W., Knauss, Kevin G., Kovscek, Anthony, Law, David, Lippmann, Marcelo J., Majer, Ernest L., Meer, Bert van der, Moline, Gerry, Newmark, Robin L., Oldenburg, Curtis M., Orr, Franklin M., Pruess, Karsten, Tsang, Chin-Fu, Myer, Larry R., Myer, Larry R., Benson, Sally M., Byrer, Charles, Cole, David, Doughty, Christine A., Gunter, William, Hoversten, G. Michael, Hovorka, Susan, Johnson, James W., Knauss, Kevin G., Kovscek, Anthony, Law, David, Lippmann, Marcelo J., Majer, Ernest L., Meer, Bert van der, Moline, Gerry, Newmark, Robin L., Oldenburg, Curtis M., Orr, Franklin M., Pruess, Karsten, and Tsang, Chin-Fu

Published
2002

30. The GEO-SEQ project: A status report

Author

Benson, Sally M., Benson, Sally M., Myer, Larry R., Byrer, Charles, Cole, David, Doughty, Christine A., Gunter, William, Hoversten, G. Michael, Hovorka, Susan, Johnson, James W., Knauss, Kevin G., Kovscek, Anthony, Law, David, Lippmann, Marcelo J., Majer, Ernest L., Meer, Bert van der, Moline, Gerry, Newmark, Robin L., Oldenburg, Curtis M., Orr, Franklin M., Pruess, Karsten, Tsang, Chin-Fu, Benson, Sally M., Benson, Sally M., Myer, Larry R., Byrer, Charles, Cole, David, Doughty, Christine A., Gunter, William, Hoversten, G. Michael, Hovorka, Susan, Johnson, James W., Knauss, Kevin G., Kovscek, Anthony, Law, David, Lippmann, Marcelo J., Majer, Ernest L., Meer, Bert van der, Moline, Gerry, Newmark, Robin L., Oldenburg, Curtis M., Orr, Franklin M., Pruess, Karsten, and Tsang, Chin-Fu

Published
2002

31. The GEO-SEQ project: A status report

Author

Myer, Larry R., Myer, Larry R., Benson, Sally M., Byrer, Charles, Cole, David, Doughty, Christine A., Gunter, William, Hoversten, G. Michael, Hovorka, Susan, Johnson, James W., Knauss, Kevin G., Kovscek, Anthony, Law, David, Lippmann, Marcelo J., Majer, Ernest L., Meer, Bert van der, Moline, Gerry, Newmark, Robin L., Oldenburg, Curtis M., Orr, Franklin M., Pruess, Karsten, Tsang, Chin-Fu, Myer, Larry R., Myer, Larry R., Benson, Sally M., Byrer, Charles, Cole, David, Doughty, Christine A., Gunter, William, Hoversten, G. Michael, Hovorka, Susan, Johnson, James W., Knauss, Kevin G., Kovscek, Anthony, Law, David, Lippmann, Marcelo J., Majer, Ernest L., Meer, Bert van der, Moline, Gerry, Newmark, Robin L., Oldenburg, Curtis M., Orr, Franklin M., Pruess, Karsten, and Tsang, Chin-Fu

Published
2002

34. The GEO-SEQ project: A status report

Author

Benson, Sally M., Benson, Sally M., Myer, Larry R., Byrer, Charles, Cole, David, Doughty, Christine A., Gunter, William, Hoversten, G. Michael, Hovorka, Susan, Johnson, James W., Knauss, Kevin G., Kovscek, Anthony, Law, David, Lippmann, Marcelo J., Majer, Ernest L., Meer, Bert van der, Moline, Gerry, Newmark, Robin L., Oldenburg, Curtis M., Orr, Franklin M., Pruess, Karsten, Tsang, Chin-Fu, Benson, Sally M., Benson, Sally M., Myer, Larry R., Byrer, Charles, Cole, David, Doughty, Christine A., Gunter, William, Hoversten, G. Michael, Hovorka, Susan, Johnson, James W., Knauss, Kevin G., Kovscek, Anthony, Law, David, Lippmann, Marcelo J., Majer, Ernest L., Meer, Bert van der, Moline, Gerry, Newmark, Robin L., Oldenburg, Curtis M., Orr, Franklin M., Pruess, Karsten, and Tsang, Chin-Fu

Published
2002

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