High Frequency Dielectric Measurement Tool
First Claim
1. A dielectric logging tool that comprises:
- a first transmitter antenna;
a second transmitter antenna spaced axially from the first transmitter antenna; and
three axially spaced receiver antennas positioned between the first and second transmitter antennas,wherein each of the transmitter and receiver antennas are horn antennas.
2 Assignments
0 Petitions
Accused Products
Abstract
Disclosed dielectric logging tools and methods employ three or more receive horn antennas positioned between at least two transmit antennas, which can also be horn antennas. The logging tools can operate in the range between 100 MHz and 10 GHz to provide logs of formation permittivity, formation conductivity, standoff distance, and electrical properties of material in the standoff gap. Logs of water-saturated porosity and/or oil movability can be readily derived. The presence of additional receive antennas offers a significantly extended operating range, additional depths of investigation, increased measurement accuracy, and further offers compensation for tool standoff and mudcake effects. In both wireline and logging while drilling embodiments, at least some disclosed dielectric logging tools employ a set of three axially-spaced receive antennas positioned between pairs of axially-spaced transmit antennas. At least some disclosed methods employ absolute amplitude and phase measurements in response to alternate firings of the transmit antennas.
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Citations
22 Claims
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1. A dielectric logging tool that comprises:
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a first transmitter antenna; a second transmitter antenna spaced axially from the first transmitter antenna; and three axially spaced receiver antennas positioned between the first and second transmitter antennas, wherein each of the transmitter and receiver antennas are horn antennas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A logging method that comprises:
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moving a logging tool along a borehole, wherein the logging tool comprises at least three receive antennas positioned between at least two transmit antennas; measuring characteristics of a receive signal with each of the at least three receive antennas in response to operation of each of the at least two transmit antennas; determining formation permittivity values based at least in part on said characteristics; and associating the permittivity values with tool position to provide a dielectric log. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. An information storage medium having software comprising:
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a measurement module that obtains measurements made via at least three receive antennas in response to two antennas spaced in opposite axial directions from the receive antennas; a tool module that predicts tool measurements based on estimated formation properties; an inversion module that adjusts estimated formation properties until predictions of the tool module match the measurements obtained by the measurement module; and a display module that provides a log of at least one formation property as a function of tool position or depth. - View Dependent Claims (19, 20, 21, 22)
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Specification