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Jack K Odum - One of the best experts on this subject based on the ideXlab platform.

  • comparison of p and s wave velocity profiles obtained from surface seismic refraction reflection and Downhole Data
    Tectonophysics, 2003
    Co-Authors: Robert A Williams, William J Stephenson, Jack K Odum
    Abstract:

    High-resolution seismic-reflection/refraction Data were acquired on the ground surface at six locations to compare with near-surface seismic-velocity Downhole measurements. Measurement sites were in Seattle, WA, the San Francisco Bay Area, CA, and the San Fernando Valley, CA. We quantitatively compared the Data in terms of the average shear-wave velocity to 30-m depth (Vs30), and by the ratio of the relative site amplification produced by the velocity profiles of each Data type over a specified set of quarter-wavelength frequencies. In terms of Vs30, similar values were determined from the two methods. There is <15% difference at four of the six sites. The Vs30 values at the other two sites differ by 21% and 48%. The relative site amplification factors differ generally by less than 10% for both P- and S-wave velocities. We also found that S-wave reflections and first-arrival phase delays are essential for identifying velocity inversions. The results suggest that seismic reflection/refraction Data are a fast, non-invasive, and less expensive alternative to Downhole Data for determining Vs30. In addition, we emphasize that some P- and S-wave reflection travel times can directly indicate the frequencies of potentially damaging earthquake site resonances. A strong correlation between the simple S-wave first-arrival travel time/apparent velocity on the ground surface at 100 m offset from the seismic source and the Vs30 value for that site is an additional unique feature of the reflection/refraction Data that could greatly simplify Vs30 determinations.

  • Comparison of P- and S-wave velocity profiles obtained from surface seismic refraction/reflection and Downhole Data
    Tectonophysics, 2003
    Co-Authors: Robert A Williams, William J Stephenson, Jack K Odum
    Abstract:

    High-resolution seismic-reflection/refraction Data were acquired on the ground surface at six locations to compare with near-surface seismic-velocity Downhole measurements. Measurement sites were in Seattle, WA, the San Francisco Bay Area, CA, and the San Fernando Valley, CA. We quantitatively compared the Data in terms of the average shear-wave velocity to 30-m depth (Vs30), and by the ratio of the relative site amplification produced by the velocity profiles of each Data type over a specified set of quarter-wavelength frequencies. In terms of Vs30, similar values were determined from the two methods. There is

Kais Gzara - One of the best experts on this subject based on the ideXlab platform.

  • Real-Time Formation Integrity Tests Using Downhole Data
    Distributed Computing, 2013
    Co-Authors: Iain M. Rezmer-cooper, Frederick Henry Kreisler Rambow, Mike M. Arasteh, Mohamed Hashem, Bruce Swanson, Kais Gzara
    Abstract:

    Accurate leakoff/formation-integrity tests are essential for efficient management of equivalent circulating density within the safe pressure window. Traditionally, the rate of Downhole buildup is estimated from the standpipe pressure but now can be monitored directly with a Downhole annular-pressure measurement. Low flow rates used during a leakoff/formation-integrity test preclude use of traditional measurement-while-drilling (MWD) systems to transmit Data to the surface. However, by use of a wireline coupling tool, Downhole pressure can be transmitted to surface in real time, allowing the operator to view the surface and Downhole pressure buildup simultaneously and evaluate both formation integrity and mud compressibility.

  • Real-time formation-integrity tests with Downhole Data
    Journal of Petroleum Technology, 2000
    Co-Authors: Iain M. Rezmer-cooper, Frederick Henry Kreisler Rambow, Mike M. Arasteh, Bruce Swanson, M. N. Hashem, Kais Gzara
    Abstract:

    Accurate leakoff/formation-integrity tests are essential for efficient management of equivalent circulating density within the safe pressure window. Traditionally, the rate of Downhole buildup is estimated from the standpipe pressure but now can be monitored directly with a Downhole annular-pressure measurement. Low flow rates used during a leakoff/formation-integrity test preclude use of traditional measurement-while-drilling (MWD) systems to transmit Data to the surface. However, by use of a wireline coupling tool, Downhole pressure can be transmitted to surface in real time, allowing the operator to view the surface and Downhole pressure buildup simultaneously and evaluate both formation integrity and mud compressibility.

Robert A Williams - One of the best experts on this subject based on the ideXlab platform.

  • comparison of p and s wave velocity profiles obtained from surface seismic refraction reflection and Downhole Data
    Tectonophysics, 2003
    Co-Authors: Robert A Williams, William J Stephenson, Jack K Odum
    Abstract:

    High-resolution seismic-reflection/refraction Data were acquired on the ground surface at six locations to compare with near-surface seismic-velocity Downhole measurements. Measurement sites were in Seattle, WA, the San Francisco Bay Area, CA, and the San Fernando Valley, CA. We quantitatively compared the Data in terms of the average shear-wave velocity to 30-m depth (Vs30), and by the ratio of the relative site amplification produced by the velocity profiles of each Data type over a specified set of quarter-wavelength frequencies. In terms of Vs30, similar values were determined from the two methods. There is <15% difference at four of the six sites. The Vs30 values at the other two sites differ by 21% and 48%. The relative site amplification factors differ generally by less than 10% for both P- and S-wave velocities. We also found that S-wave reflections and first-arrival phase delays are essential for identifying velocity inversions. The results suggest that seismic reflection/refraction Data are a fast, non-invasive, and less expensive alternative to Downhole Data for determining Vs30. In addition, we emphasize that some P- and S-wave reflection travel times can directly indicate the frequencies of potentially damaging earthquake site resonances. A strong correlation between the simple S-wave first-arrival travel time/apparent velocity on the ground surface at 100 m offset from the seismic source and the Vs30 value for that site is an additional unique feature of the reflection/refraction Data that could greatly simplify Vs30 determinations.

  • Comparison of P- and S-wave velocity profiles obtained from surface seismic refraction/reflection and Downhole Data
    Tectonophysics, 2003
    Co-Authors: Robert A Williams, William J Stephenson, Jack K Odum
    Abstract:

    High-resolution seismic-reflection/refraction Data were acquired on the ground surface at six locations to compare with near-surface seismic-velocity Downhole measurements. Measurement sites were in Seattle, WA, the San Francisco Bay Area, CA, and the San Fernando Valley, CA. We quantitatively compared the Data in terms of the average shear-wave velocity to 30-m depth (Vs30), and by the ratio of the relative site amplification produced by the velocity profiles of each Data type over a specified set of quarter-wavelength frequencies. In terms of Vs30, similar values were determined from the two methods. There is

S. Ballard - One of the best experts on this subject based on the ideXlab platform.

  • The surface area modulation Downhole telemetry system for measurement while drilling
    1998
    Co-Authors: A.j. Mansure, R.g. Keefe, T.w.h. Caffey, L.c. Bartel, S. Ballard
    Abstract:

    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 conductive drillstring. The electrical resistance of this gap can be modulated to alter the electrical characteristics of a circuit involving a surface power supply, the sections of the drillstring above and below the gap, the earth, and a nearby return electrode. These changes alter the current in the circuit, which can be monitored at the surface with an ammeter. Downhole Data are encoded and transmitted to the surface as a pattern of current oscillations. In a field test, the SAM system successfully transmitted Downhole information from depths of 1,400 ft below the fluid level to the surface at a rate of 110 baud. Electrical insulation on the outside of the simulated drillstring was required to achieve this level of performance. Electrically insulated tubing improved the Data transmission rate at a given depth by more than an order of magnitude, and increased the maximum depth frommore » which successful Data telemetry could be achieved by more than a factor of two.« less

  • Field tests of the surface area modulation Downhole telemetry system
    1997
    Co-Authors: R.g. Keefe, S. Ballard
    Abstract:

    Two field tests of the surface area modulation (SAM) Downhole wireless telemetry system were performed at the DOE Rocky Mountain Oilfield Testing Center near Casper, Wyoming in November, 1995 and September, 1996. SAM telemetry involves the introduction of a gap of electrically insulating material in the tubular conductors in the well. The electrical resistance of a switch in this gap can then be modulated to alter the electrical characteristics of a circuit involving the well tubulars. These changes affect the current in the circuit, which is monitored with a surface ammeter. Downhole Data are encoded and transmitted to the surface as a pattern of current oscillations. The tests successfully demonstrated the ability of the system to transmit information from depths exceeding 2,000 feet to the surface at up to 2,400 baud.

Iain M. Rezmer-cooper - One of the best experts on this subject based on the ideXlab platform.

  • Real-Time Formation Integrity Tests Using Downhole Data
    Distributed Computing, 2013
    Co-Authors: Iain M. Rezmer-cooper, Frederick Henry Kreisler Rambow, Mike M. Arasteh, Mohamed Hashem, Bruce Swanson, Kais Gzara
    Abstract:

    Accurate leakoff/formation-integrity tests are essential for efficient management of equivalent circulating density within the safe pressure window. Traditionally, the rate of Downhole buildup is estimated from the standpipe pressure but now can be monitored directly with a Downhole annular-pressure measurement. Low flow rates used during a leakoff/formation-integrity test preclude use of traditional measurement-while-drilling (MWD) systems to transmit Data to the surface. However, by use of a wireline coupling tool, Downhole pressure can be transmitted to surface in real time, allowing the operator to view the surface and Downhole pressure buildup simultaneously and evaluate both formation integrity and mud compressibility.

  • Real-time formation-integrity tests with Downhole Data
    Journal of Petroleum Technology, 2000
    Co-Authors: Iain M. Rezmer-cooper, Frederick Henry Kreisler Rambow, Mike M. Arasteh, Bruce Swanson, M. N. Hashem, Kais Gzara
    Abstract:

    Accurate leakoff/formation-integrity tests are essential for efficient management of equivalent circulating density within the safe pressure window. Traditionally, the rate of Downhole buildup is estimated from the standpipe pressure but now can be monitored directly with a Downhole annular-pressure measurement. Low flow rates used during a leakoff/formation-integrity test preclude use of traditional measurement-while-drilling (MWD) systems to transmit Data to the surface. However, by use of a wireline coupling tool, Downhole pressure can be transmitted to surface in real time, allowing the operator to view the surface and Downhole pressure buildup simultaneously and evaluate both formation integrity and mud compressibility.