摘要:
A method of determining the acoustic impedance of a fluid in a borehole, by gating a reflected acoustic signal into a plurality of time slots, and comparing received energies of the signal for the time slots to obtain a value indicative of the acoustic impedance of the fluid. The value may be normalized to yield the acoustic impedance of the fluid using the acoustic impedance of, e.g., water as a calibration point. The comparison is performed by comparing a ratio of an integration of a first ring down time slot and a second ring down time slot, to an integration of an internal reflection time slot. The acoustic pulse may be generated using a transducer immersed in an intermediate fluid contained within a chamber defined in part by a plate in contact with the borehole fluid and having a thickness such that a mechanical resonance frequency of the plate in a thickness mode is substantially equal to a resonance frequency of the transducer. The sonic velocity of the fluid is also measured and, when combined with the acoustic impedance, is used to determine the fluid density.
摘要:
The acoustic impedance of a fluid in a borehole is determined by gating a reflected acoustic signal into a plurality of time slots, and comparing received energies of the signal for the time slots to obtain a value indicative of the acoustic impedance of the fluid. The value may be normalized to yield the acoustic impedance of the fluid using the acoustic impedance of, e.g., water as a calibration point. The acoustic pulse may be generated using a transducer immersed in an intermediate fluid contained within a chamber defined in part by a plate in contact with the borehole fluid and having a thickness such that a mechanical resonance frequency of the plate in a thickness mode is substantially equal to a resonance frequency of the transducer. The sonic velocity of the fluid is also measured and, when combined with the acoustic impedance, is used to determine fluid density.
摘要:
A method of determining the acoustic impedance of a fluid in a borehole, by gating a reflected acoustic signal into a plurality of time slots, and comparing received energies of the signal for the time slots to obtain a value indicative of the acoustic impedance of the fluid. The value may be normalized to yield the acoustic impedance of the fluid using the acoustic impedance of, e.g., water as a calibration point. The comparison is performed by comparing a ratio of an integration of a first ring down time slot and a second ring down time slot, to an integration of an internal reflection time slot. The acoustic pulse may be generated using a transducer immersed in an intermediate fluid contained within a chamber defined in part by a plate in contact with the borehole fluid and having a thickness such that a mechanical resonance frequency of the plate in a thickness mode is substantially equal to a resonance frequency of the transducer. The sonic velocity of the fluid is also measured and, when combined with the acoustic impedance, is used to determine the fluid density.
摘要:
An ultrasonic scanner tool employs a transducer that excites a target plate at a known distance from the transducer. One side of the target plate forms a chamber that in operation is filled with wellbore fluid. On the other side of the target plate, a chamber is formed containing a vacuum or a fluid with a significantly lower acoustic impedance than the wellbore fluid and the target plate, allowing an improved measurement of the acoustic impedance of the wellbore fluid.
摘要:
An ultrasonic scanner tool employs a transducer that excites a target plate at a known distance from the transducer. One side of the target plate forms a chamber that in operation is filled with wellbore fluid. On the other side of the target plate, a chamber is formed containing a vacuum or a fluid with a significantly lower acoustic impedance than the wellbore fluid and the target plate, allowing an improved measurement of the acoustic impedance of the wellbore fluid.