System and Method for Downhole Signal Enhancement

Abstract

A system and method for downhole signal enhancement. The system includes a downhole tool having one or more sensors coupled thereto. The one or more sensors may measure internal pressure and one or more parameters selected from the group consisting of external pressure, pressure sensor temperature, weight on bit, torque on bit, bending moment, roll gyro, tangential acceleration, radial acceleration, and axial acceleration. A noise estimator may be coupled to the downhole tool and estimate a downhole noise component in the one or more parameters. A telemetry modulator may be coupled to the downhole tool and generate a signal that includes the estimated downhole noise component and a telemetry component. The downhole noise component in the signal may be reduced based at least partially upon the estimate.

What is claimed is: 
     
         1 . A system for downhole signal enhancement, comprising:
 a downhole tool having one or more sensors coupled thereto, wherein the one or more sensors are adapted to measure internal pressure and one or more parameters selected from the group consisting of external pressure, pressure sensor temperature, weight on bit, torque on bit, bending moment, roll gyro, tangential acceleration, radial acceleration, and axial acceleration;   a noise estimator coupled to the downhole tool and adapted to estimate a downhole noise component in the one or more parameters; and   a telemetry modulator coupled to the downhole tool and adapted to generate a signal, wherein the signal includes the estimated downhole noise component and a telemetry component, and wherein the downhole noise component in the signal is reduced based at least partially upon the estimate.   
     
     
         2 . The system of  claim 1 , wherein the noise estimator comprises a filter that identifies the downhole noise component in the one or more parameters. 
     
     
         3 . The system of  claim 2 , wherein the filter comprises a Wiener filter or an adaptive filter. 
     
     
         4 . The system of  claim 1 , wherein a first of the one or more sensors is positioned above the telemetry modulator, and a second of the one or more sensors is positioned below the telemetry modulator. 
     
     
         5 . The system of  claim 1 , wherein the one or more parameters are selected from the group consisting of weight on bit, torque on bit, and axial acceleration. 
     
     
         6 . A method for downhole signal enhancement, comprising:
 measuring one or more parameters with one or more sensors coupled to a downhole tool, wherein the one or more parameters are selected from the group consisting of external pressure, pressure sensor temperature, weight on bit, torque on bit, bending moment, roll gyro, tangential acceleration, radial acceleration, and axial acceleration;   estimating a downhole noise component in the one or more parameters;   generating a signal that includes the estimated downhole noise component and a telemetry component; and   reducing the downhole noise component in the signal based at least partially upon the estimate.   
     
     
         7 . The method of  claim 6 , further comprising measuring internal pressure with one of the one or more sensors. 
     
     
         8 . The method of  claim 6 , wherein the one or more parameters are selected from the group consisting of weight on bit, torque on bit, and axial acceleration. 
     
     
         9 . The method of  claim 6 , wherein the signal is a mud pulse signal, and wherein the mud pulse signal is generated via a telemetry modulator. 
     
     
         10 . The method of  claim 9 , wherein a first of the one or more sensors is positioned above the telemetry modulator, and a second of the one or more sensors is positioned below the telemetry modulator. 
     
     
         11 . The method of  claim 6 , wherein the downhole noise component is generated by a mud motor, a rotary steerable system, rotation of a drill pipe, mechanical interaction between a drill string and a formation, mechanical interaction between a drill bit and the formation, or a combination thereof. 
     
     
         12 . The method of  claim 6 , wherein the generated signal is modified based upon the estimated downhole noise component, and wherein modification of the generated signal comprises switching a frequency of the generated signal, switching a modulation rate of the generated signal, switching a data rate of the generated signal, or a combination thereof 
     
     
         13 . The method of  claim 6 , wherein measuring the one or more parameters occurs after the signal is generated. 
     
     
         14 . The method of  claim 6 , wherein the signal is transmitted from the downhole tool to a surface location. 
     
     
         15 . The method of  claim 6 , wherein the signal is transmitted from a surface location to the downhole tool. 
     
     
         16 . A computer program embodied on a non-transitory computer readable medium that, when executed by a processor, controls a method for downhole signal enhancement, comprising:
 measuring one or more parameters with one or more sensors coupled to a downhole tool, wherein the one or more parameters are selected from the group consisting of external pressure, pressure sensor temperature, weight on bit, torque on bit, bending moment, roll gyro, tangential acceleration, radial acceleration, and axial acceleration;   estimating a downhole noise component in the one or more parameters;   generating a signal that includes the estimated downhole noise component and a telemetry component; and   reducing the downhole noise component in the signal based at least partially upon the estimate.   
     
     
         17 . The computer program of  claim 16 , wherein the one or more parameters are selected from the group consisting of weight on bit, torque on bit, and axial acceleration. 
     
     
         18 . The computer program of  claim 16 , wherein the signal is a mud pulse signal that is transmitted via a telemetry modulator. 
     
     
         19 . The computer program of  claim 18 , wherein a first of the one or more sensors is positioned above the telemetry modulator, and a second of the one or more sensors is positioned below the telemetry modulator. 
     
     
         20 . The computer program of  claim 16 , wherein the downhole noise component is generated by a mud motor, a rotary steerable system, rotation of a drill pipe, mechanical interaction between a drill string and a formation, mechanical interaction between a drill bit and the formation, or a combination thereof.