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US 6,151,554 AGranted
Method and apparatus for computing drill bit vibration power spectral density
AssigneeDresser Industries, Inc.
InventorPaul F. Rodney
Life of this patent
Estimating the term…
Abstract
A power spectrum density processor is located near the drill bit while drilling. The power spectral density processor computes the power spectral density of the vibrations generated by the drill bit while drilling. The power spectral density information is telemetered to the surface where it is used to enhance drill bit seismic techniques.
Claims24
A drill bit seismic system comprising
- a downhole transducer sensitive to the vibrations of a drill bit, the drill bit coupled to a drill string, the downhole transducer producing a downhole transducer signal representative of the vibrations of the drill bit;
- a downhole power spectral density processor configured to compute the downhole power spectral density of the downhole transducer signal;
- the downhole transducer and the downhole power spectral density processor being located near the drill bit during drilling operations;
- a surface transducer, coupled to the drill string substantially at the surface, sensitive to the vibrations in the drill string, the surface transducer producing a surface transducer signal representative of the vibrations in the drill string;
- a surface power spectral density processor configured to compute the surface power spectral density of the surface transducer signal;
- and
- a drill string transfer function magnitude estimator configured to estimate the magnitude of the transfer function of the drill string from the drill bit to the surface using the downhole power spectral density and the surface power spectral density.
4 more elements
A drill bit seismic system comprising
- a drill bit coupled to a drill string;
- a drill string transfer function estimator configured to estimate a drill string transfer function magnitude by computing a downhole power spectral density of a signal representative of the vibrations of the drill bit and a surface power spectral density of a signal representative of the vibrations of the drill string substantially at the surface;
- a lateral motion transducer coupled to the drill string near the drill bit, the lateral motion transducer being sensitive to lateral motion of the drill bit, the lateral motion transducer producing a lateral motion transducer signal;
- the lateral motion transducer signal being coupled to the drill string transfer function estimator;
- and
- the drill string transfer function estimator being configured to filter the effects of the lateral motion of the drill bit on the estimate of the transfer function of the drill string.
3 more elements
A method for using drill bit vibration spectral density in a drill bit seismics system comprising
- sensing drill bit vibrations;
- computing the drill bit power spectral density of the sensed drill bit vibrations;
- sensing vibrations in the drill string at the surface;
- computing the surface power spectral density of the sensed drill string vibrations;
- and
- estimating a transfer function of the drill string using the drill bit power spectral density and the surface power spectral density.
3 more elements
Dependencies are inferred from the claim text.