Acoustic data transmission through a drillstring

Claim 3

The method of claim 1 wherein said preconditioned data signal is a first electrical signal, said method further comprising; converting said first electrical signal to a first acoustical signal for application to said first end of said drill string; and converting said detected acoustical signal to a detected electrical signal at said second end of said drill string.

Claim 4

The method of claim 2 wherein: said drillstring has low attenuation passbands and high attenuation stopbands of acoustical signals, the frequencies of said first acoustical signal being in the passbands of said drillstring.

Claim 5

The method of claim 1 further comprising the step of: suppressing acoustical echoes from each end of said drillstring.

Claim 10

The method of claim 6 wherein said step of suppressing acoustical echoes at the transmitter end of said drillstring comprises applying energy to said drill string in a position adjacent to said transmitter.

Claim 13

Apparatus for the transmission of data on a continuous carrier wave through a drillstring comprising a plurality of drill pipe sections connected end-to-end by tool joints, the length and cross-sectional area of the pipe sections being different from the length and cross-sectional area of the tool joints, said apparatus comprising: transmitter means for coupling data to said drillstring near a first end of said drillstring for acoustical transmission to a second end of said drillstring; anti-noise means near said first end of said drillstring for preventing acoustical noise from said first end from being transmitted through said drillstring to said second end, wherein said anti-noise means comprises: first noise-receiving means for providing a first output indicative of acoustical noise traveling from said first end toward said transmitter means, and for providing no indication of acoustical noise traveling from said transmitter means towards said first end; and noise-cancelling means for applying a delay output from said noise-receiving means to said transmitting means to cancel noise traveling from said transmitting means towards said second end of said drill string; and receiving means near said second end for receiving said acoustically transmitted data.

Claim 14

Apparatus for the transmission of data on a continuous carrier wave through a drillstring comprising a plurality of drill pipe sections connected end-to-end by tool joints, the length and cross-sectional area of the pipe sections being different from the length and cross-sectional area of the tool joints, said apparatus comprising: transmitter means for coupling data to said drillstring near a first end of said drillstring for acoustical transmission to a second end of said drillstring; anti-noise means near said first end of said drillstring for preventing acoustical noise from said first end from being transmitted through said drillstring to said second end, wherein said anti-noise means comprises: first noise-receiving means for providing a first output indicative of acoustical noise traveling from said first end toward said transmitter means, and for providing no indication of acoustical noise traveling from said transmitter means towards said first end; and noise-cancelling means for applying a delay output from said noise-receiving means to said transmitting means to cancel noise traveling from said transmitting means towards said second end of said drill string; and receiving means near said second end for receiving said acoustically transmitted data.

Claim 15

The apparatus of claim 9 wherein said anti-noise means further comprises: second noise-receiving means for providing a second output indicative of acoustical noise and data traveling from said transmitter means towards said second end, and for providing no indication of acoustical noise traveling from said second end towards said transmitter means; and adaptive control means for comparing said second output with said data, and adjusting at least one of said first and second outputs of said transmitted data to minimize the transmission of noise towards said second end.

Claim 16

Apparatus for the transmission of data on a continuous carrier wave through a drillstring comprising a plurality of drill pipe sections connected end-to-end by tool joints, the length and cross-sectional area of the pipe sections being different from the length and cross-sectional area of the tool joints, said apparatus comprising: transmitter means for coupling data to said drillstring near a first end of said drillstring for acoustical transmission to a second end of said drillstring, wherein said transmitting means comprises: a first and a second acoustical transmitter spaced along said drill string a distance equal to an odd multiple of a quarter wavelength of said carrier wave, said first transmitter being closer to said first end than said second transmitter; first signal applying means for applying a delayed, inverted, data signal to said first transmitter, the delay being equal to the transmission time of the transmitted signal from said first transmitter to said second transmitter, whereby said data signal is transmitted only toward said second end; and second signal applying means for applying said data signal to said second transmitter; anti-noise means near said first end of said drillstring for preventing acoustical noise from said first end from being transmitted through said drillstring to said second end; and receiving means near said second end for receiving said acoustically transmitted data.

Claim 17

Apparatus for the transmission of data on a continuous carrier wave through a drillstring comprising a plurality of drill pipe sections connected end-to-end by tool joints, the length and cross-sectional area of the pipe sections being different from the length and cross-sectional area of the tool joints, said apparatus comprising: transmitter means for coupling data to said drillstring near a first end of said drillstring for acoustical transmission to a second end of said drillstring, wherein said transmitting means comprises: a first and a second acoustical transmitter spaced along said drill string a distance equal to an odd multiple of a quarter wavelength of said carrier wave, said first transmitter being closer to said first end than said second transmitter; first signal applying means for applying a delayed, inverted, data signal to said first transmitter, the delay being equal to the transmission time of the transmitted signal from said first transmitter to said second transmitter, whereby said data signal is transmitted only toward said second end; and second signal applying means for applying said data signal to said second transmitter; anti-noise means near said first end of said drillstring for preventing acoustical noise from said first end from being transmitted through said drillstring to said second end; and receiving means near said second end for receiving said acoustically transmitted data.

Claim 18

The apparatus of claim 9 wherein said first noise receiving means comprises: a first and a second acoustical receiver spaced along said drillstring a distance equal to an odd multiple of a quarter wavelength of the carrier wave, said first receiver being between said first end and said second receiver, said second receiver being between said first receiver and said transmitting means; means for summing a noise signal from said first receiver and a delayed, inverted noise signal from said second receiver to produce a noise-cancelling signal, the delay being equal to the transmission time of the received noise signal from said first receiver to said second receiver; and the delay of said noise-cancelling means being equal to the transmission time of said noise from said second receiver to said transmitting means.

Claim 19

The apparatus of claim 10 wherein said second noise-receiving means comprises: third and fourth acoustical receivers spaced along said drillstring a distance equal to an odd multiple of a quarter wavelength of said carrier wave, said receivers being between said transmitter means and said second end, said third receiver being between said fourth receiver and said transmitter means; means for summing a signal from said third receiver and a delayed, inverted noise signal from said fourth receiver to produce a noise cancelling signal, the delay being equal to the transmission time of the received noise signal from said third receiver to said fourth receiver.

Claim 20

The apparatus of claim 11 wherein each of said acoustical transmitters comprise: a transducer for converting an electrical signal into an acoustical signal for application to said drillstring; and said receiving means comprises output transducer means for converting said received acoustical data to a detected electrical signal at said second end of said drillstring.

Claim 21

The apparatus of claim 9 wherein said drillstring further comprises a drill collar at said first end of said drillstring, said transmitting means and anti-noise means being affixed to said drill collar.

Claim 22

The apparatus of claim 9 further including means for preconditioning said data to counteract distortions caused by said drill string.

Claim 23

The apparatus of claim 9 wherein: the acoustical impedance of said receiving means is matched to the acoustical impedance of said drillstring at said second end, thereby preventing the generation of echoes from said second end towards said first end of said drillstring.

Claim 26

The method of transmitting data through a drill string as in claim 18, wherein the step of applying said data signal to the drill string includes: generating a signal which travels up the drill string while substantially suppressing the travel of the signal down the drill string.

Claim 27

The method of transmitting data through a drill string as in claim 19 wherein the step of substantially suppressing travel of the signal down the drill string includes: generating signals in the drill string at two downhole locations spaced apart axially along the drill string by a distance of approximately one quarter wavelength of the center frequency of said one passband.

Claim 28

The method of transmitting data through a drill string as in claim 20 including: delaying the signal applied to the more downhole of the two locations by a time equal to b/c, where b is one quarter wavelength of said center frequency and c is the speed of sound in the drill string in the vicinity of the two downhole locations.

Claim 29

The method of transmitting data through a drill string as in claim 18 wherein the step of actively suppressing echoes includes: sensing, at a location below said first location, and generating a noise signal corresponding only to acoustic energy moving up the drill string; and cancelling said noise signal.

Claim 30

The method of claim 22 wherein the step of sensing and generating a noise signal corresponding only to acoustic energy moving up the drill string includes: sensing the outputs from two sensors spaced apart axially along the drill string by a distance of approximately one quarter wavelength of the center frequency of said passband; and delaying and inverting one of said outputs relative to the other by a time equal to b/c, where b is one quarter wavelength of said center frequency and c is the speed of sound in the drill string.

Claim 31

The method of claim 23 further including the step of: summing said outputs and applying the summed output to generate a signal which cancels noise travelling up the drill string.

Claim 32

The method of claim 18 further including the step of: conditioning the data signal to compensate for distortion caused by the passbands of the drill string.

Claim 33

The method of claim 25 wherein the step of conditioning the data includes: multiplying each frequency component of the data signal by exp (-ikL), where L is the transmission length of the drill string, k is the wave number in said drill string at the frequency of each component, and i is √-1.

Claim 34

Apparatus for transmitting data through a drill string having a plurality of drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints, the apparatus comprising: signal generator means for generating a continuous wave data signal having a frequency content in at least one passband of the drill string; transmitter means for applying said data signal to the drill string at said first location for transmission to said second location; suppression means for actively suppressing echoes in the drill string resulting from transmission of the data signal; and detecting means for detecting the data signal at said second location.

Claim 35

Apparatus for transmitting data through a drill string having a plurality of drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints, the apparatus comprising: signal generator means for generating a continuous wave data signal having a frequency content in at least one passband of the drill string; transmitter means for applying said data signal to the drill string at said first location for transmission to said second location; suppression means for actively suppressing echoes in the drill string resulting from transmission of the data signal; and detecting means for detecting the data signal at said second location.

Claim 36

The apparatus for transmitting data through a drill string as in claim 27, wherein said transmitter means includes: means for generating a signal which travels up the drill string while substantially suppressing the travel of the signal down the drill string.

Claim 37

The apparatus for transmitting data through a drill string as in claim 28 wherein said means for substantially suppressing travel of the signal down the drill string includes: transducer means for generating signals in the drill string at two downhole locations spaced apart axially along the drill string by a distance of approximately one quarter wavelength of the center frequency of said one passband.

Claim 38

The apparatus for transmitting data through a drill string as in claim 29 including: delay means for delaying the signal applied to the more downhole of the two locations by a time equal to b/c, where b is one quarter wavelength of said center frequency and c is the speed of sound in the drill string in the vicinity of the two downhole locations.

Claim 39

The apparatus for transmitting data through a drill string as in claim 27 wherein said suppression means includes: transducer means for sensing, at a location below said first location, and generating a noise signal corresponding only to acoustic energy moving up the drill string; and cancelling said noise signal.

Claim 40

The apparatus of claim 31 wherein said transducer means for sensing and generating a noise signal Corresponding only to acoustic energy moving up the drill string includes: first and second transducers spaced apart axially along the drill string by a distance of approximately one quarter wavelength of the center frequency of said passband; and delaying and inverting one of said outputs relative to the other by a time equal to b/c, where b is one quarter wavelength of said center frequency and c is the speed of sound in the drill string.

Claim 41

The apparatus of claim 32 further including: means for summing said outputs and applying the summed output to generate a signal which cancels noise travelling up the drill string.

Claim 42

The apparatus of claim 27 further including: means for conditioning the data signal to compensate for distortion caused by the passbands of the drill string.

Claim 43

The apparatus of claim 34 wherein the means for conditioning the data includes: means for multiplying each frequency component of the data signal by exp (-ikL), where L is the transmission length of the drill string, k is the wave number in said drill string at the frequency of each component, and i is √-1.

Claim 46

The method of transmitting data through a drill string as in claim 36 including: delaying the signal applied to the more downhole of the two locations by a time equal to b/c, where b is one quarter wavelength of said center frequency and c is the speed of sound in the drill string in the vicinity of the two downhole locations.

Claim 49

The method of claim 38 further including the step of: summing said outputs and applying the summed output to generate a signal which cancels noise travelling up the drill string.

Claim 52

Apparatus for transmitting data through a drill string having a plurality of drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints, the apparatus comprising: signal generator means for generating a continuous wave data signal having a frequency content in at least one passband of the drill string; transmitter means for applying said data signal to the drill string at said first location for transmission to said second location; suppression means for actively suppressing echoes in the drill string resulting from transmission of the data signal; detecting means for detecting the data signal at said second location; wherein said transmitter means includes; means for generating a signal which travels up the drill string while substantially suppressing the travel of the signal down the drill string; and wherein said means for substantially suppressing travel of the signal down the drill string includes; transducer means for generating signals in the drill string at two downhole locations spaced apart axially along the drill string by a distance of approximately one quarter wavelength of the center frequency of said one passband.

Claim 53

Apparatus for transmitting data through a drill string having a plurality of drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints, the apparatus comprising: signal generator means for generating a continuous wave data signal having a frequency content in at least one passband of the drill string; transmitter means for applying said data signal to the drill string at said first location for transmission to said second location; suppression means for actively suppressing echoes in the drill string resulting from transmission of the data signal; detecting means for detecting the data signal at said second location; wherein said transmitter means includes; means for generating a signal which travels up the drill string while substantially suppressing the travel of the signal down the drill string; and wherein said means for substantially suppressing travel of the signal down the drill string includes; transducer means for generating signals in the drill string at two downhole locations spaced apart axially along the drill string by a distance of approximately one quarter wavelength of the center frequency of said one passband.

Claim 54

The apparatus for transmitting data through a drill string as in claim 41 including: delay means for delaying the signal applied to the more downhole of the two locations by a time equal to b/c, where b is one quarter wavelength of said center frequency and c is the speed of sound in the drill string in the vicinity of the two downhole locations.

Claim 55

Apparatus for transmitting data through a drill string having a plurality of drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints, the apparatus comprising: signal generator means for generating a continuous wave data signal having a frequency content in at least one passband of the drill string; transmitter means for applying said data signal to the drill string at said first location for transmission to said second location; suppression means for actively suppressing echoes in the drill string resulting from transmission of the data signal; detecting means for detecting the data signal at said second location; wherein said suppression means includes; transducer means for sensing, at a location below said first location, and generating a noise signal corresponding only to acoustic energy moving up the drill string; and cancelling said noise signal; and wherein said transducer means for sensing and generating a noise signal corresponding only to acoustic energy moving up the drill string includes; first and second transducers spaced apart axially along the drill string by a distance of approximately one quarter wavelength of the center frequency of said passband; and delaying and inverting one of said outputs relative to the other by a time equal to b/c, where b is one quarter wavelength of said center frequency and c is the speed of sound in the drill string.

Claim 56

Apparatus for transmitting data through a drill string having a plurality of drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints, the apparatus comprising: signal generator means for generating a continuous wave data signal having a frequency content in at least one passband of the drill string; transmitter means for applying said data signal to the drill string at said first location for transmission to said second location; suppression means for actively suppressing echoes in the drill string resulting from transmission of the data signal; detecting means for detecting the data signal at said second location; wherein said suppression means includes; transducer means for sensing, at a location below said first location, and generating a noise signal corresponding only to acoustic energy moving up the drill string; and cancelling said noise signal; and wherein said transducer means for sensing and generating a noise signal corresponding only to acoustic energy moving up the drill string includes; first and second transducers spaced apart axially along the drill string by a distance of approximately one quarter wavelength of the center frequency of said passband; and delaying and inverting one of said outputs relative to the other by a time equal to b/c, where b is one quarter wavelength of said center frequency and c is the speed of sound in the drill string.

Claim 57

The apparatus of claim 43 further including: means for summing said outputs and applying the summed output to generate a signal which cancels noise travelling up the drill string.

Claim 58

Apparatus for transmitting data through a drill string having a plurality of drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints, the apparatus comprising: signal generator means for generating a continuous wave data signal having a frequency content in at least one passband of the drill string; transmitter means for applying said data signal to the drill string at said first location for transmission to said second location; suppression means for actively suppressing echoes in the drill string resulting from transmission of the data signal; detecting means for detecting the data signal at said second location; means for conditioning the data signal to compensate for distortion caused by the passbands of the drill string; and wherein the means for conditioning the data includes; p1 means for multiplying each frequency component of the data signal by exp (-ikL), where L is the transmission length of the drill string, k is the wave number in said drill string at the frequency of each component, and i is √-1.

Claim 59

Apparatus for transmitting data through a drill string having a plurality of drill pipe sections connected end-to-end by joints from a first location below the surface of the earth to a second location at or near the surface of the earth, the length and cross-sectional area of the drill pipe sections being different from the length and cross-sectional area of the joints, the apparatus comprising: signal generator means for generating a continuous wave data signal having a frequency content in at least one passband of the drill string; transmitter means for applying said data signal to the drill string at said first location for transmission to said second location; suppression means for actively suppressing echoes in the drill string resulting from transmission of the data signal; detecting means for detecting the data signal at said second location; means for conditioning the data signal to compensate for distortion caused by the passbands of the drill string; and wherein the means for conditioning the data includes; p1 means for multiplying each frequency component of the data signal by exp (-ikL), where L is the transmission length of the drill string, k is the wave number in said drill string at the frequency of each component, and i is √-1.