Method for compensating drill pipe and near-borehole effect on and electronic noise in transient resistivity measurements
AssigneeBaker Hughes Incorporated
InventorsTsili Wang, Roland E. Chemali
Life of this patent
Estimating the term…
Abstract
Transient measurements made at two spaced apart receivers responsive to separate activation of two transmitters symmetrically disposed about the two receivers. The transmitters and receivers are on an instrument having a conductive body induces currents in the earth formation. The effect of the conductive body is removed by using deconvolving the signal at one receiver using the measured signal at the other receiver. The symmetric transmitter configuration also enables compensation for receiver differences.
Claims14
An apparatus configured to estimate a value of a resistivity property of an earth formation, the apparatus comprising:
- a tool configured to be conveyed in a borehole;
- at least one transmitter and at least one receiver on the tool, the at least one transmitter and at least one receiver defining two transmitter-receiver combinations, the at least one transmitter configured to induce a current in the earth formation, the at least one receiver configured to produce a transient signal responsive to the induced current, the transient signal being responsive to a conductive body of the tool;
- and
- at least one processor configured to estimate the value of the resistivity property deconvolving a first transient signal corresponding to a first one of the two transmitter-receiver combinations using a second transient signal corresponding to a second one of the two transmitter-receiver combinations, the estimate being substantially unaffected by the conductive body of the tool.
A method of estimating a value of a resistivity property of an earth formation, the method comprising:
- conveying a tool in a borehole;
- using at least one transmitter and at least one receiver on the tool to define two transmitter-receiver combinations,
- using the at least one transmitter to induce a current in the earth formation,
- using the at least one receiver configured to produce a transient signal responsive to the induced current, the transient signal being responsive to a conductive body of the tool;
- and
- estimating the value of the resistivity property deconvolving a first transient signal corresponding to a first one of the two transmitter-receiver combinations using a second transient signal corresponding to a second one of the two transmitter-receiver combinations, the estimate being substantially unaffected by the conductive body of the tool.
A non-transitory computer-readable medium product having thereon instructions that when read by at least one processor, cause the at least one processor to execute a method, the method comprising:
- estimating a value of a resistivity property of an earth formation by deconvolving a first transient signal using a second transient signal produced by at least one receiver on a logging tool responsive to activation of a transmitter on the logging tool, the first transient signal and the second transient signal being affected by a conductive body of the tool, the estimate being substantially unaffected by the conductive body of the tool.
Dependencies are inferred from the claim text.