Noise detection and suppression system and method for wellbore telemetry
First Claim
1. A noise filtering apparatus for wellbore telemetry data signals, comprising:
- a receiver located on the surface and adapted to receive a wellbore telemetry data signal, said telemetry data signal including data which represents one or more downhole measurements conducted downhole during a drilling operation, the data being unknown to the receiver prior to reception;
a transformer in communication with said receiver and adapted to transform at least part of the telemetry data signal to generate therefrom a spectrum of at least part of the telemetry data signal;
an approximator in communication with said transformer adapted to generate an approximation of a noise-free spectrum of the at least part of the telemetry data signal;
a ratio calculator in communication with said approximator adapted to generate a dimensionless spectrum by calculating the ratio of the spectrum of at least part of the telemetry data signal and the approximation of a noise-free spectrum; and
an identifier in communication with said ratio calculator adapted to analyze the dimensionless spectrum and select frequencies from said dimensionless spectrum that are characterized by a substantial level of noise.
1 Assignment
0 Petitions
Accused Products
Abstract
Methods and apparatus are described for identifying and removing noise from borehole telemetry signals. A spectrum of the signal and of an approximated noise-free spectrum of the signals are generated and compared so as to identify frequencies at which noise occurs. The approximated spectrum is preferably generated by an averaging or integrating process which essentially results in a smoothened variant of the signal spectrum. The comparison includes dividing the signal spectrum by the approximated spectrum, and setting a threshold in the resulting dimensionless peak spectrum. The remaining parts of the peak spectrum are identified as noise. The dimensionless spectrum is found to have major advantages when having to identify noise frequencies.
-
Citations
22 Claims
-
1. A noise filtering apparatus for wellbore telemetry data signals, comprising:
-
a receiver located on the surface and adapted to receive a wellbore telemetry data signal, said telemetry data signal including data which represents one or more downhole measurements conducted downhole during a drilling operation, the data being unknown to the receiver prior to reception; a transformer in communication with said receiver and adapted to transform at least part of the telemetry data signal to generate therefrom a spectrum of at least part of the telemetry data signal; an approximator in communication with said transformer adapted to generate an approximation of a noise-free spectrum of the at least part of the telemetry data signal; a ratio calculator in communication with said approximator adapted to generate a dimensionless spectrum by calculating the ratio of the spectrum of at least part of the telemetry data signal and the approximation of a noise-free spectrum; and an identifier in communication with said ratio calculator adapted to analyze the dimensionless spectrum and select frequencies from said dimensionless spectrum that are characterized by a substantial level of noise. - View Dependent Claims (2, 3, 4, 5, 6, 20, 21)
-
-
7. A wellbore telemetry apparatus for gathering data related to subsurface conditions and for transmitting said data to the surface, said apparatus comprising:
-
a first transducer located in a well adapted and configured to convert data gathered in the well into signals to be in operation transmitted to said surface; a second transducer located on said surface adapted and configured to reconvert said signals into processable data; and a processor in communication with said second transducer adapted and configured to process said processable data, the processor characterized in that said processor comprises a transformer for generating a signal spectrum of at least a part of the processable data, an approximator for generating an approximation of a noise-free spectrum of said at least a part of said processable data, and a ratio generator adapted to compute the ratio of said signal spectrum and said approximation of a noise-free spectrum so as to identify noise frequencies.
-
-
8. A method for identifying a frequency or range of frequencies of noise in a wellbore telemetry data signal, comprising the steps of:
-
receiving a wellbore telemetry data signal using a receiver located on the surface, said telemetry data signal including data which represents one or more downhole measurements gathered downhole during a drilling operation, the data being unknown to the receiver on the surface prior to reception; transforming at least part of the telemetry data signal to generate therefrom a spectrum of at least part of the telemetry data signal; generating an approximation of a noise-free spectrum of the at least part of the telemetry data signal; generating a dimensionless spectrum by calculating a ratio of the spectrum of at least part of the telemetry data signal and the approximation of a noise-free spectrum; and identifying noise frequencies by analyzing the dimensionless spectrum and selecting frequencies from said dimensionless spectrum. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 22)
-
Specification