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US 10,539,698 B2Granted
Determining a quantitative bond using signal attenuation
AssigneeSchlumberger Technology Corporation
InventorsVivian Pistre, Toshihiro Kinoshita
Life of this patent
Estimating the term…
Abstract
A technique facilitates determination of a quantitative bond between a pipe and adjacent materials, e.g. between a wellbore casing and adjacent cement. The quantitative bond is established via acoustic measurements related to signal attenuation. Additionally, the acoustic measurements may be conducted with a sonic tool during a wellbore operation, e.g. during a drilling operation. The methodology enables use of signal attenuation in a manner which facilitates determination of bond index coverage up to a high percentage, e.g. 100 percent.
Claims18
A method of evaluating bonding of cement in a wellbore, comprising:
- providing, as a drill collar that is part of a drill string, a bond analysis tool with a transmitter and a plurality of receivers;
- delivering the bond analysis tool downhole along an interior of a pipe having pipe sections;
- emitting sonic signals via the transmitter for propagation along the pipe until received by the plurality of receivers;
- processing an amplitude of a received combination of propagating sonic signals inside the drill collar and inside the pipe, wherein the propagating sonic signals comprise a combination of a propagating drill collar signal and a propagating pipe signal;
- computing an apparent attenuation of the propagating sonic signals, wherein a range of apparent attenuations increases with amount of transmitter signal energy imparted to the drill collar as the propagating drill collar signal;
- and
- using the apparent attenuation between various pairs of receivers of the plurality of receivers as being dependent on a ratio of the propagating drill collar signal to the propagating pipe signal and attenuation in a receiver section of the drill collar to extract the attenuation in the pipe for evaluation of bonding between the pipe and a surrounding cement.
4 more elements
A method, comprising:
- providing, as a drill collar that is part of a drill string, a bond analysis tool with a transmitter and a plurality of receivers;
- delivering the bond analysis tool into a pipe and emitting a signal via the transmitter;
- processing an amplitude of a combination of propagating signals resulting from the signal emitted by the transmitter and received by the plurality of receivers;
- computing an apparent attenuation of the propagating signals, wherein the propagating signals comprise a combination of a propagating drill collar signal and a propagating pipe signal and wherein a range of apparent attenuations increases with amount of transmitter signal energy imparted to the drill collar as the propagating drill collar signal;
- employing the apparent attenuation between various pairs of receivers of the plurality of receivers, as being dependent on a ratio of the propagating drill collar signal to the propagating pipe signal and attenuation in a receiver section of the drill collar, to extract the attenuation in the pipe;
- and
- using the attenuation in the pipe to determine whether sections of the pipe are free or constrained.
4 more elements
A system, comprising:
- a wellbore lined with a casing and cement located along an exterior of the casing;
- a logging-while-drilling tool that is in the form of a drill collar that is deployable as part of a drill string into the casing via a conveyance, the logging-while-drilling tool having a transmitter to provide a sonic signal and a plurality of receivers position to receive combinations of propagating signals resulting from the sonic signal;
- and
- a processor-based control system coupled with the logging-while-drilling tool to process amplitudes of the combinations of propagating signals, to compute an apparent attenuation of the propagating signals, and to determine the apparent attenuation between various pairs of receivers of the plurality of receivers to extract the attenuation in the casing, as being dependent on a ratio of a propagating drill collar signal to a propagating casing signal and attenuation in a receiver section of the drill collar, for evaluation of bonding between the casing and the cement, wherein a range of apparent attenuations increases with amount of transmitter sonic signal energy imparted to the drill collar as the propagating drill collar signal.
1 more element
Dependencies are inferred from the claim text.