EP0408667A1 - Acoustic data transmission through a drill string. - Google Patents
Acoustic data transmission through a drill string.Info
- Publication number
- EP0408667A1 EP0408667A1 EP89905949A EP89905949A EP0408667A1 EP 0408667 A1 EP0408667 A1 EP 0408667A1 EP 89905949 A EP89905949 A EP 89905949A EP 89905949 A EP89905949 A EP 89905949A EP 0408667 A1 EP0408667 A1 EP 0408667A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- drill string
- noise
- acoustical
- signal
- data
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000005540 biological transmission Effects 0.000 title claims description 39
- 230000003111 delayed effect Effects 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims description 24
- 238000002592 echocardiography Methods 0.000 claims description 13
- 230000000694 effects Effects 0.000 claims description 6
- 230000003044 adaptive effect Effects 0.000 claims description 4
- 230000001419 dependent effect Effects 0.000 claims description 3
- 230000008878 coupling Effects 0.000 claims description 2
- 238000010168 coupling process Methods 0.000 claims description 2
- 238000005859 coupling reaction Methods 0.000 claims description 2
- 230000005534 acoustic noise Effects 0.000 abstract description 2
- 239000011324 bead Substances 0.000 abstract 2
- 230000000630 rising effect Effects 0.000 abstract 1
- 238000005553 drilling Methods 0.000 description 10
- 238000004458 analytical method Methods 0.000 description 9
- 238000012360 testing method Methods 0.000 description 8
- 238000004364 calculation method Methods 0.000 description 6
- 238000012545 processing Methods 0.000 description 5
- 230000004044 response Effects 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 230000001629 suppression Effects 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000002596 correlated effect Effects 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 239000003208 petroleum Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 241001494467 Asinus Species 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000002706 hydrostatic effect Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000003319 supportive effect Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
- E21B47/14—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling using acoustic waves
- E21B47/16—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling using acoustic waves through the drill string or casing, e.g. by torsional acoustic waves
Definitions
- This invention relates generally to a sj'stem for transmitting data along a drill string, and more particularly to a system for transmitting data through a drill string by mod ⁇ ulation of intermediate-frequency acoustic carrier waves.
- Deep wells of the type commonly used for petroleum or geothermal exploration are typically less than 30 cm (12 inches) in diameter and on the order of 2 km (1.5 miles) long. These wells are drilled using drill strings assembled from relatively light sections (either 30 or 45 feet long) of drill pipe that are connected end-to-end by tool joints, additional sections being added to the uphole end as the hole deepens.
- the downhole end of the drill string typically includes a drill collar, a dead weight assembled from sections of relatively hcavj ⁇ lengths of uniform diameter collar pipe having an overall length on the order of 300 meters (1000 feet).
- a drill bit is attached to the downhole end of the drill collar, the weight of the collar causing the bit to bite into the earth as the drill string is rotated from the surface.
- Drilling mud or air is pumped from the surface to the drill bit through an axial hole in the drill string. This fluid removes the cuttings from the hole, provides a hydrostatic head which controls the formation gases, and sometimes provides cooling for the bit.
- This invention is directed towards the acoustical transmission of data through the met l drill string.
- the history of such efforts is recorded in columns 2 - 4 of U.S. Patent No. 4,293,93G, issued Oct. 6, 1981, of Cox and Chaney.
- the first efforts were in the late 1940's by Sun Oil Company, which organization concluded there was too much attenuation in the drill string for the technology at that time. Another company came to the same conclusion during this period.
- Figure 1 shows some of the results of the new analysis of the data recorded by Cox and Chaney. This figure is a plot of the power amplitude versus frequency of the transmitted signal. The theoretical boundaries between the passbands and the stopbands are shown by the vertical dotted lines. If this figure is compared to Figure 1 . Cox and Chaney's patent, significant and obvious differences can be noted. These are attributable to error in Cox and Chaney's analysis.
- a modulated continuous acoustical carrier wave (waves) whicli is (are) centered within one (several) of the passbands of the drill string.
- the present invention may comprise transmitting means for coupling data to a drill string near a first end of said drill string for acoustical transmission to a second end of said drill string; anti- noise means near the first end of said drill string for preventing acoustical noise from the first end from being transmitted through the drill string to the second end; and receiving means near the second end for receiving the acoustically transmitted data.
- the invention may further comprise a method comprising the steps of preconditioning the data to counteract distortions caused by the drill string, the distortions corresponding to the effects of multiple passbands and stopbands having characteristics dependent upon the properties of the drill string; applying the precon ⁇ ditioned data to a first end of the drill string; and detecting the data at a second end of the drill string.
- Fig. 1 shows the measured frequency response within two passbands of the Cox- and-Chaney drill string.
- Fig. 2 shows the calculated frequency response within two passbands of the Cox- and-Chaney drill string.
- Fig. 3 shows a drill string.
- Fig. 4 shows dispersion curves for a uniform string (dashed line) and a typical drill string (solid line).
- Fig. 5 shows the transmission arrangement at a first end of a drill string.
- this invention involves the transmission of acoustical data along a drill string 10 which consists of a plurality of lengths of constant diameter drill pipe 15 fastened end-to-end at thicker diameter joint portions 18 by means of screw threads as is well known in this art.
- Lower end 12 of drill string 10 may include a length of constant diameter drill collar to provide downward force to drill bit 22.
- a constant diameter mud channel 24 extends axially through each component of drill string 10 to provide a path for drilling mud to be pumped from the surface at upper end 14 through holes in drill bit 22 as is well known in this art.
- drill string 10 is terminated in conventional structure such as a derrick, rotary pinion, and kelly, represented by box 25, to permit additional lengths of drill pipe to be added to the string, and the string to be rotated for drilling. Details of this conventional string structure may be found in the aforementioned patent of E. Hixon.
- impedance z pac
- total axial force F(x, t) — cz -
- p density
- a .urea
- c speed of sound over a cross-section of a slender
- elastic, rod u is the displacement
- x is the position
- m is the Lagrangian mass coordinate
- t is the time.
- each piece of drill pipe consists of a tube of length d-*, mass density l 5 cross-sectional area ⁇ -* , speed of sound c* . , and mass ri; and a tool joint of length -_" 2 , mass density 2. cross-sectional area ⁇ 2 , speed of sound c 2 , and mass r 2 .
- a procedure demonstrated at page 180 of Brillouin has been used with the Floquet theorem to generate the following eigenvalue problem:
- Equation IS of Barnes et al. the wave number
- i ⁇ /z ⁇
- / the frequency being transmitted.
- Equation IS of Barnes et al. the present examination shows Barnes' "W" to be kd.
- i Brillouin shows that frequencies which yield real solutions for k are banded and separated by frequency bands which yield complex solutions for k. He calls these two types of regions passbands and stopbands. The attenuation in the stopbands is generally quite large. Within each of the passbands the value of the phase velocity ⁇ /k depends upon the value of ⁇ .
- the drill string functions as an acoustic comb filter, ' and frequencies which propagate in the passbands are dispersed. Thus, signals which have broad frequency spectra are severely distorted by passage through a drill string. However, signal processing techniques can be- used to remove this distortion.
- comb filter refers to the gross structure in the frequency spectrum which is produced by the stopbands and the pass- bands, where each tooth of the comb is an individual passband.
- Sharp's reference to a comb refers to a fine structure which exists within each passband.
- Figure 4 shows a plot of the characteristic determinate of Equation 2 using values for p ⁇ , a. ⁇ , C ⁇ , and d ⁇ representative of actual drill pipe parameters.
- the straight dotted line represents the solution for a unifor drill string, e.g., one where the diameter of the joints is equal to the diameter of the pipe.
- the velocity of propagation for a given frequency is represented by the phase velocity.
- this ratio is constant and equal to the bar velocity of steel.
- the gaps represent stopbands. This analysis predicts the same values for the boundaries between the stopbands and the passbands as that of Barnes et al.; however, it also shows the characteristics of wave propagation within each of the passbands- Barnes et al. did not predict the distortion resulting from the effects of the passbands .
- Fig. 2 shows the third and fourth passbands of a fast Fourier transform of the waveform which results from a signal which represents, to a rough approximation, the hammer blow used in the Cox and Chaney field test. This signal has a relatively narrow frequency content which only stimulates the third and fourth passband of the drill string.
- Ten sections of drill pipe were used in this field test, and the ends of the drill string produced nearly perfect reflection of the acoustic waves which resulted from the hammer blows.
- This figure shows the "fine structure" of Sharp et al. to be caused by standing wave resonances within the drill string.
- the number of spikes in each passband correlates with the number of sections of pipe in the drill string, as explained in greater detail in the Appendix.
- the analysis suggests the following technique for processing data signals and com ⁇ pensating for the effects of the stopbands and dispersion.
- First transmit information continuously (as opposed to a broad-band pulse mode) and only within the passbands and away from the edges of the stopbands.
- Second compensate for dispersion by mul ⁇ tiplying each frequency component by exp(— ikL), where L is the transmission length in the drill pipe section 18 of the drill string. Where a large amount of acoustical noise is present, such as would be caused by a drill bit or drill mud, it is preferable to transform the data signal before transmission, resulting in an undispersed signal at the receiver position.
- the foregoing analysis is based on the assumption that echos are suppressed at each end of the drill string. This is necessary to eliminate the spikes or fine structure within each of the passbands. It is common knowledge that signal processing is effective when echo strength is 20 dB below the the signal level. Each time the acoustic wave interacts with the intersection of the drill pipe and the drill collar 80, the signal weakens by 6 dB. Also, from the analysis of Cox and Chaney's field test, the signal attenuates about 2 dB/1000 feet. Therefore, an echo which is generated by a reflection of the data signal at the top of the drill string 14 will lose 6 + 41, dB as it travels back down the drill string to 80 and then returns to the receiver. Thus, if the drill pipe section has a length of 3500 feet or more, the echos from the receiving end of the string will be naturally attenuated to an acceptable level.
- a terminating transducer For shorter drill strings, additional echo suppression will be required. This can be accomplished with a device called a terminating transducer. This device has an acoustical impedance which matches the acoustical impedance of the drill string and an acoustical loss factor which is sufficient to make up the required 20 dB of echo suppression.
- the terminating transducers must have a stiffness equal to the elastic component and a damping coefficient equal to the viscous component. Practically, the response need only make up the difference between 20 dB
- the characteristic impedance is a function of frequency and position, the position dependence being periodic in accordance with the period of the drill string. Calculations show that tool joints are not a good location for a termination because the impedance is a sensitive function of position.
- For the fourth passband a location 1/3 or 2/3 along
- termination transducers is a conventional problem to those of ordinary skill in that art provided with the impedance data from Equation 2.
- This device could consist of a ring of polarized PZT ceramic elements and an electronic circuit whose reactive and resistive components are adjusted to tune the transducer to
- Echo suppression is a more critical problem at the downhole end of the drill string where echos travel freely up and down the drill collar section and confuse the transmis ⁇ sion of data. At this location, it is useful to use noise cancellation techniques both to suppress echos and to prevent the noise of the drill bit or drilling mud from interfering with the desired data signal uphole.
- a noise cancellation technique for use with this invention is disclosed hereinafter.
- Fig. 5 shows a section 30 of dri 1 ! collar 20 located relatively close to downhole end
- this apparatus includes a transmitter 40 for transmitting data uphole, but not downhole, a sensor 50 for detecting acoustical noise from downhole and applying it to transmitter 40 to cancel the uphole transmission of the noise, and a
- sensor 60 for providing adaptive control to transmitter 40 and sensor 50 to minimize uphole transmission of noise.
- Transmitter 40 includes a pair of spaced transducers 42, 44 for converting an electrical input signal into acoustical energy in drill collar 30.
- Each transducer may be a magnetostrictive ring element with a winding of insulated conducting wire.
- transducers are spaced apart a distance b equal to one quarter wavelength of the center frequency of the passband selected for transmission.
- a data signal from source 28 is applied directly to uphole transducer 44, preferably through a summing circuit 46.
- the data signal is also applied to transducer 42 through a delay circuit 47 and an inverting circuit 48.
- Delay circuit 47 has a delay value equal to distance b divided by
- transducers 42, 44 provide an acoustical signal 2 , F 4 that travels both uphole and downhole. Accordingly the resulting upward and downward waves from both transducers are:
- Equation 8 solves to
- ⁇ u ( ⁇ ) —2Asm( ⁇ b/c) sm( ⁇ ) (9)
- transmitter 40 transmits an uphole signal having approximately twice the amplitude A of the applied signal, and no downhole signal.
- Noise sensor 50 includes a pair of spaced sensors 52, 54 which operate in a similar manner to provide an indication of acoustic energy moving uphole, and no indication of
- the output of sensor 52 which sensor may be an accelerom- eter or strain gauge, is an electrical signal that is summed in summing circuit 56 with the output of similar sensor 54, which output is delayed by dela ⁇ - circuit 57 and and inverted by inverting circuit 58. If the delay of circuit 57 is equal to the spacing b divided by the speed of sound c, downward moving energy is first detected by sensor
- ⁇ (t) 2Asin( ⁇ //2/ 0 ) cos ⁇ (t - b/c) (10) where o is the center frequency of the passband.
- the error is zero at the center of the transmission band and is only .03 at the band edges, a result showing 30 db noise cancellation.
- adaptive control 70 a con ⁇ ventional control circuit that has an input from a second pair of sensors 62, 64. These sensors, identical to sensors 52, 54, also have corresponding delay circuit 67 and in- verter 68 to provide an output indicative of an upward moving wave and no output in response to a downward moving wave.
- the upward moving wave at control sensors 60 is a mixture of the noise and data that passed transmitter 40. Accordingly, by delaying the data signal in delay circuit 72 and adding the result to the output of sensors 60 with summing circuit 74, an error signal is produced which indicates the effectiveness of noise cancelation.
- This signal is fed into an adaptive control circuit 70 which controls conventional circuitry 75 to adjust voltage amplitudes or phases of the signals being applied to any of sensors 52 and 62 or transmitters 42, 44 to minimize the amount of noise being transmitted upward towards the surface.
- the spacing _ between sensors or transmitters in the third passband would be about 30 cm (78 inches) or about 21 cm (53 inches) in the fourth passband.
- the operation of the invention is as follows:
- the circuitry of Fig. 5 is mounted on a drill collar, including suitable circuitry 28 for generating data representative of a down- hole parameter.
- Power supplies such as batteries or mud-driven electrical generators, and other supportive circuitry known to those of ordinary skill in the art, would also be incorporated into drill collar 30.
- the drill bit and mud create acoustic noise that travels in both directions through drill string 10. Downward noise is not sensed by the sensors; however, upward noise, including echos from the bottom of the drill collar, are sensed by sensor circuit 50 and applied to transmitter circuit 40, yielding a greatly reduced upward noise component. Primarily the data travels to the connection 80 (Fig.
- the data from circuit 28 may be precompensated by multiplying each frequency component of the signal by exp(— ikL) to adjust for the distortion caused by the passbands of the drill string.
- Such compensation may be accomplished by any manner known to those of ordinary skill in the art with a device such as an analog-to- digital signal processing circuit.
- This invention recognizes and solves the problems noted by many previous workers in the field of transmitting data along a drill string.
- quality transmission on continuous acoustic carrier waves without extensive downhole circuitry, and without the use of impractical repeater circuits and transducers along the drill string is possible at frequencies on the order of several hundred to several thousand Hertz. These frequencies are high in relation to the ambient drilling noise (about 1 to 10 Hz), and therefore allow transmission relatively free of this noise. Also the bandwidths of the passbands allow data rates far in excess of present mud pulse systems. Also it is recognized that this method will work in drilling situations where air is used instead of mud.
- the particular sizes and equipment discussed above are cited merely to illustrate a particular embodiment of this invention.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Acoustics & Sound (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- Remote Sensing (AREA)
- Fluid Mechanics (AREA)
- Environmental & Geological Engineering (AREA)
- Geophysics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Earth Drilling (AREA)
Abstract
Des signaux acoustiques sont transmis au travers d'un cordon de tubes de forage (30) en supprimant le bruit acoustique montant et en préconditionnant les données en reconnaissance des caractéristiques d'impédance du filtre à peigne du cordon de tubes de forage. Des détecteurs espacés (52, 54) envoient un signal retardé à un additionneur (46); ce signal est combiné à un signal provenant d'un circuit approprié (28) puis il est appliqué à des détecteurs (42, 44) pour transmettre un signal montant dépourvu de bruit descendant.Acoustic signals are transmitted through a bead of drill pipe (30) by suppressing rising acoustic noise and by preconditioning the data in recognition of the impedance characteristics of the comb filter of the bead of drill pipe. Spaced detectors (52, 54) send a delayed signal to an adder (46); this signal is combined with a signal from an appropriate circuit (28) then it is applied to detectors (42, 44) to transmit an uplink signal devoid of downward noise.
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US18432688A | 1988-04-21 | 1988-04-21 | |
US184326 | 1988-04-21 |
Related Child Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19930111079 Division EP0565141A3 (en) | 1988-04-21 | 1989-04-21 | Acoustic data transmission through a drill string |
EP93111079.5 Division-Into | 1993-07-10 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0408667A1 true EP0408667A1 (en) | 1991-01-23 |
EP0408667A4 EP0408667A4 (en) | 1991-08-14 |
EP0408667B1 EP0408667B1 (en) | 1994-01-19 |
Family
ID=22676440
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19890905949 Expired - Lifetime EP0408667B1 (en) | 1988-04-21 | 1989-04-21 | Acoustic data transmission through a drill string |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0408667B1 (en) |
JP (1) | JPH03501408A (en) |
DE (1) | DE68912584D1 (en) |
WO (1) | WO1989010572A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102010047568A1 (en) | 2010-04-12 | 2011-12-15 | Peter Jantz | Device for transmitting information about drill pipe |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5151882A (en) * | 1990-08-08 | 1992-09-29 | Atlantic Richfield Company | Method for deconvolution of non-ideal frequency response of pipe structures to acoustic signals |
GB2249852A (en) * | 1990-10-29 | 1992-05-20 | Sandia Corp | Circuit for echo and noise suppression of acoustic signals transmitted through a drillstring |
NO306522B1 (en) * | 1992-01-21 | 1999-11-15 | Anadrill Int Sa | Procedure for acoustic transmission of measurement signals when measuring during drilling |
EP0552833B1 (en) * | 1992-01-21 | 1996-11-06 | Anadrill International SA | Sonic vibration telemetering system |
JP2000121742A (en) | 1998-10-14 | 2000-04-28 | Mitsubishi Electric Corp | Transmitter for transmitting excavation shell sound and method for transmitting excavation shell sound |
US6370082B1 (en) | 1999-06-14 | 2002-04-09 | Halliburton Energy Services, Inc. | Acoustic telemetry system with drilling noise cancellation |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4293936A (en) * | 1976-12-30 | 1981-10-06 | Sperry-Sun, Inc. | Telemetry system |
US4562559A (en) * | 1981-01-19 | 1985-12-31 | Nl Sperry Sun, Inc. | Borehole acoustic telemetry system with phase shifted signal |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4066995A (en) * | 1975-01-12 | 1978-01-03 | Sperry Rand Corporation | Acoustic isolation for a telemetry system on a drill string |
US4156229A (en) * | 1977-01-31 | 1979-05-22 | Sperry-Sun, Inc. | Bit identification system for borehole acoustical telemetry system |
US4283780A (en) * | 1980-01-21 | 1981-08-11 | Sperry Corporation | Resonant acoustic transducer system for a well drilling string |
US4282588A (en) * | 1980-01-21 | 1981-08-04 | Sperry Corporation | Resonant acoustic transducer and driver system for a well drilling string communication system |
-
1989
- 1989-04-21 EP EP19890905949 patent/EP0408667B1/en not_active Expired - Lifetime
- 1989-04-21 WO PCT/US1989/001641 patent/WO1989010572A1/en active IP Right Grant
- 1989-04-21 JP JP50585689A patent/JPH03501408A/en active Pending
- 1989-04-21 DE DE89905949T patent/DE68912584D1/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4293936A (en) * | 1976-12-30 | 1981-10-06 | Sperry-Sun, Inc. | Telemetry system |
US4562559A (en) * | 1981-01-19 | 1985-12-31 | Nl Sperry Sun, Inc. | Borehole acoustic telemetry system with phase shifted signal |
Non-Patent Citations (1)
Title |
---|
See also references of WO8910572A1 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102010047568A1 (en) | 2010-04-12 | 2011-12-15 | Peter Jantz | Device for transmitting information about drill pipe |
Also Published As
Publication number | Publication date |
---|---|
DE68912584D1 (en) | 1994-03-03 |
EP0408667A4 (en) | 1991-08-14 |
JPH03501408A (en) | 1991-03-28 |
EP0408667B1 (en) | 1994-01-19 |
WO1989010572A1 (en) | 1989-11-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6535458B2 (en) | Method and apparatus for suppressing drillstring vibrations | |
US5128901A (en) | Acoustic data transmission through a drillstring | |
US5148408A (en) | Acoustic data transmission method | |
US5274606A (en) | Circuit for echo and noise suppression of accoustic signals transmitted through a drill string | |
US5477505A (en) | Downhole pipe selection for acoustic telemetry | |
US7158446B2 (en) | Directional acoustic telemetry receiver | |
US5222049A (en) | Electromechanical transducer for acoustic telemetry system | |
US7911879B2 (en) | Method of detecting signals in acoustic drill string telemetry | |
US5969638A (en) | Multiple transducer MWD surface signal processing | |
US5050132A (en) | Acoustic data transmission method | |
US5124953A (en) | Acoustic data transmission method | |
US6847585B2 (en) | Method for acoustic signal transmission in a drill string | |
US5056067A (en) | Analog circuit for controlling acoustic transducer arrays | |
US5128902A (en) | Electromechanical transducer for acoustic telemetry system | |
US7210555B2 (en) | Low frequency acoustic attenuator for use in downhole applications | |
US10637529B2 (en) | Signal equalisation | |
US20070153629A1 (en) | Acoustic isolator | |
US5541890A (en) | Method for predictive signal processing for wireline acoustic array logging tools | |
EP0408667A1 (en) | Acoustic data transmission through a drill string. | |
CA2691410C (en) | Parallel-path acoustic telemetry isolation system and method | |
EP0565141A2 (en) | Acoustic data transmission through a drill string | |
Shin | Signal attenuation simulation of acoustic telemetry in directional drilling | |
Alenezi | Experimental Results On the Drill String Design for Borehole Acoustic Communicatio | |
GB2249852A (en) | Circuit for echo and noise suppression of acoustic signals transmitted through a drillstring | |
Farraj | Acoustical communications for wireless downhole telemetry systems |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19900411 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB NL |
|
A4 | Supplementary search report drawn up and despatched |
Effective date: 19910626 |
|
AK | Designated contracting states |
Kind code of ref document: A4 Designated state(s): DE FR GB NL |
|
17Q | First examination report despatched |
Effective date: 19921012 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB NL |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Effective date: 19940119 Ref country code: FR Effective date: 19940119 Ref country code: DE Effective date: 19940119 |
|
REF | Corresponds to: |
Ref document number: 68912584 Country of ref document: DE Date of ref document: 19940303 |
|
EN | Fr: translation not filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19940620 Year of fee payment: 6 |
|
NLV1 | Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Effective date: 19950421 |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 19950421 |