Adjustable shear valve mud pulser and controls therefor

Abstract

A telemetry system involving a shear-type mud pulser valve as the preferred embodiment is described. The control system includes a motor driver for the mud pulser which, in essence, moves one movable plate with respect to a stationary plate to create openings of various sizes. Pressure is sensed uphole of the pulser valve and is compared in real time to the desired pressure pulse amplitude. By allowing different relative rotational positions of the rotatable plate with respect to the stationary plate, different amplitudes can be achieved to further enhance the transmission of data to the surface. The control system compensates for wear in the mud pulser valve itself as well as drastic changes in mud flow and pressure. The configuration is simple and not prone to fouling from grit or other particles in the mud. The system is capable of creating an initial baseline array of a variety of pulse amplitudes, and thereafter providing the required relative rotation between the stationary and rotatable plates so as to be able to duplicate the baseline pulse amplitudes despite changes in the valve condition or in the flowing conditions of the mud.

1. A control system for generating multilevel signals in a tubular string having a fluid flowpath and a downhole telemetry system using a pulser valve in said fluid flowpath, comprising:
 a pulser valve operable in multiple positions comprising a maximum and minimum open position and at least one position in between;  
 a driver connected to said pulser valve; and  
 a flowpath mounted  controller connected to said driver so asconfigured to create pressure pulses with said pulser valve by commanding said driver to re-position said pulser valve in fixed increments  independent of flow and pressure conditions of a circulating mud in the fluid flow path;  
   a sensor to sense amplitudes of the pressure pulses for use by the controller to control the pulser valve .  
 
     
     
       2. The system of  claim 1 , further comprising:
 a pressure  wherein the sensor is mounted in a position downhole to sense the amplitudes of pressure pulses created by operation of the pulser valve and communicate said measured pressures to said controller .  
 
     
     
       3. The system of  claim 2 , wherein:
 said controller is capable of creating baseline amplitudes of pressure using said sensor as feedback, each baseline amplitude corresponding to a different position of said pulser valve.  
 
     
     
       4. The system of  claim 3 , wherein:
 said controller compensates for wear in said pulser valve by using feedback from said sensor to alter at least one position of said pulser valve to achieve any desired pulse amplitude previously established as baseline.  
 
     
     
       5. The system of  claim 3 , wherein:
 said controller uses pressure  measurements of said sensor to change the pulse shape to optimize surface detection by commanding through  said driver a variation in  to vary at least one preset position corresponding to a baseline desired amplitude.  
 
     
     
       6. The system of claim  3    1 , wherein:
 said pulser valve comprises a movable plate directly driven by said driver and having at least one opening thereon and a stationary plate having at least one opening thereon.  
 
     
     
       7. The system of  claim 6 , wherein:
 said driver rotating  rotates said movable plate to alter the  an alignment between the openings on said plates to create desired pressure  amplitudes of the pressure pulses for signal transmission to the surface.  
 
     
     
       8. A control system for generating multilevel signals in a downhole telemetry system using a pulser valve, comprising:
 a pulser valve operable in multiple positions comprising a maximum and minimum open position and at least one position in between;  
 a driver connected to said pulser valve; and  
 a controller connected to said driver so as to create pulses with said pulser valve by commanding said driver to position said pulser valve;  
 a pressure  sensor mounted in a position downhole to sense the amplitudes of pressure  the pulses created by operation of said pulser valve and communicate said measured pressures  sensed amplitudes to said controller, wherein  
 said controller is capable of creating baseline amplitudes of pressure using said sensor as feedback, each baseline amplitude corresponding to a different position of said pulser valve; and  
 said controller using said sensor determines when well conditions have changed sufficiently to that the baseline amplitudes can no longer be achieved with previously set pulser valve positions, whereupon said controller establishes new positions of said pulser valve to reobtain said previously used baseline amplitudes.  
 
     
     
       9. The system of  claim 8 , wherein:
 said controller signals to the surface to the effect that  the new positions of said pulser valve are being selected to correspond to new or to the preexisting baseline pressure amplitudes .  
 
     
     
       10. A telemetry method for sending signals from downhole to the surface, comprising:
 providing a multiposition pulser valve downhole;  
 creating a plurality of pressure amplitudes  pulses with said pulser valve; and  
 providing a driver to directly position said pulser valve in predetermined increments independent of flow and pressure conditions of circulating mud so as to obtain said amplitudes  pressure pulses;  
   providing a sensor for measuring amplitudes of the pressure pulses created by said pulser valve; and    
   communicating the measured amplitudes to a controller .  
 
     
     
       11. The method of  claim 10 , further comprising:
 providing a pressure sensor for measuring amplitude of pressure pulses created by said pulser valve;  
 communicating measured pulses to a controller; and  
 regulating said driver with said controller.  
 
     
     
       12. The method of claim  11    10 , further comprising:
 using said pressure  sensor to compensate for wear in said pulser valve by having said controller direct a change in movement of said driver so as to reposition said pulser valve to obtain the  desired pressure amplitudes despite said wear.  
 
     
     
       13. The method of claim  11    10 , further comprising:
 programming said controller with a plurality of desired amplitudes; and  
 using said pressure  sensor for feedback to said controller to obtain said desired pressure amplitudes.  
 
     
     
       14. The method of claim  11   10 , further comprising:
 using said controller to change the shape of the generated  created pressure pulses by controlling the operation of said driver and in turn  said pulser valve so as to optimize surface detection of the signal  signals.  
 
     
     
       15. The method of claim  11   10 , further comprising:
 using a stationary and a rotating disc with an opening on each disc as said pulser valve;  
 driving said rotating disc directly with said driver on command from said controller; and  
 changing the opening size through said discs by said rotation of said rotating disc.  
 
     
     
       16. A telemetry method for sending signals from downhole to the surface, comprising:
 providing a multiposition pulser valve downhole;  
 creating a plurality of pressure amplitudes  pulses with said pulser valve; and  
 providing a driver to directly position said pulser valve so as to obtain said amplitudes;  
 providing a pressure  sensor for measuring amplitude of the pressure pulses created by said pulser valve;  
 communicating the measured pulses  amplitudes to a controller; and  
 regulating said driver with said controller;  
 establishing a plurality of discrete baseline amplitudes as a baseline ;  
 using said sensor in conjunction with said controller and said driver to obtain said baseline amplitudes; and  
 communicating said baseline amplitudes to the surface.  
 
     
     
       17. A telemetry method for sending signals from downhole to the surface, comprising:
 providing a multiposition pulser valve downhole;  
 creating a plurality of pressure amplitudes  pulses with said pulser valve; and  
 providing a driver to directly position said pulser valve so as to obtain said amplitudes  pressure pulses;  
 providing a pressure  sensor for measuring amplitudes of the pressure pulses created by said pulser valve;  
 communicating the measured amplitudes of the pressure pulses to a controller; and  
 regulating said driver with said controller;  
 programming said controller with a plurality of desired amplitudes; and  
 using said pressure sensor for feedback to said controller to obtain said desired amplitudes;  
 comparing the measured amplitudes to the desired amplitudes; and  
 using said controller to actuate said driver to reposition said pulser valve to allow an approach to the desired amplitude  amplitudes.  
 
     
     
       18. A telemetry method for sending signals from downhole to the surface, comprising:
 providing a multiposition pulser valve downhole;  
 creating a plurality of pressure amplitudes  pulses with said pulser valve; and  
 providing a driver to directly  position said pulser valve so as to obtain said amplitudes  pressure pulses;  
 providing a pressure sensor for measuring an amplitude of the pressure pulses created by said pulser valve;  
 communicating the measured pulse  amplitude to a controller; and  
 regulating said driver with said controller;  
 programming said controller with a plurality of desired amplitudes  amplitude; and  
 using said pressure sensor for feedback to said controller to obtain said desired amplitudes;  
 processing the measured pressure amplitude and its rate of change by said controller;  
 using said measured pressure  amplitude and rate of change information to  sending a command to said driver to alter the position of said pulser valve in a manner so as to minimize hunting or overshot of the targeted  desired amplitude.  
 
     
     
       19. A telemetry method for sending signals from downhole to the surface, comprising:
 providing a multiposition pulser valve downhole;  
 creating a plurality of pressure amplitudes  pulses with said pulser valve; and  
 providing a driver to directly  position said pulser valve so as to obtain said amplitudes  pressure pulse;  
 providing a pressure sensor for measuring amplitude  an amplitude of the pressure pulses created by said pulser valve;  
 communicating the measured pulses  amplitude to a controller; and  
 regulating said driver with said controller;  
 sensing when well flow conditions have changed to no longer permit the  a desired amplitudes  amplitude to be achieved with available positions of said pulser valve;  
 creating new baseline amplitudes with said controller for the new  changed well flow conditions;  
 communicating to the surface a signal that new baseline amplitudes have been selected  created; and  
 using the newly created baseline amplitudes for signal transmission to the surface.  
 
     
     
       20. An apparatus for generating pressure pulses in a fluid flowing in a wellbore, comprising:
   a stator in a path of the fluid;        a rotor proximate the stator, said rotor generating pressure pulses in the fluid when oriented at a plurality of positions proximate the stator; and        a driver controllably orienting the rotor in an open direction and a closed direction at the plurality of positions to obstruct flow of the fluid to generate pressure pulses in the fluid at more than one amplitude; and        a sensor for taking measurements downhole relating to the pressure pulses.     
     
     
       21. The apparatus of  claim 20 , wherein the sensor is located in the flow of the fluid. 
     
     
       22. The apparatus of  claim 20  further comprising a controller to re-orient the rotor in fixed increments. 
     
     
       23. The apparatus of  claim 20  further comprising a controller that uses the sensor measurements to change a shape of the pressure pulses to enhance detection of the pressure pulses at a surface location. 
     
     
       24. The apparatus of  claim 20 , wherein the driver is a motor that is directly coupled to the rotor. 
     
     
       25. The apparatus of  claim 20 , further comprising a controller that controls the driver in response to the sensor measurements. 
     
     
       26. The apparatus of  claim 25 , wherein the controller positions the rotor directly in response to a measured pressure. 
     
     
       27. An apparatus for generating pressure pulses in a fluid flowing in a wellbore, comprising:
   a stator in a path of the fluid;        a rotor proximate the stator, said rotor generating pressure pulses in the fluid when oriented at a plurality of positions proximate the stator;        a driver controllably orienting the rotor in an open direction and a closed direction at the plurality of positions to obstruct flow of the fluid to generate pressure pulses in the fluid at more than one amplitude; and        a controller that controls the driver to change amplitude of the pressure pulses in response to a pressure measurement made by a sensor downhole.     
     
     
       28. An apparatus for generating pressure pulses in a fluid flowing in a wellbore, comprising:
   a first member having an opening that allows the fluid to pass therethrough;        a second member that is adapted to be oriented at multiple positions to obstruct the fluid flow through the first member to generate pressure pulses having different amplitudes; and        a driver that positions the second member at the multiple positions to generate the pressure pulses having different amplitudes; and        a controller that controls the driver in response to a measurement made by a sensor downhole.     
     
     
       29. An apparatus for generating signals in a downhole fluid flow path, comprising:
   a stationary member having an opening that allows the fluid to pass therethrough;        a rotatable member having an opening and adapted to be rotated relative to the stationary member to create openings of different sizes for the fluid flow path through the stationary member to generate signals in the downhole fluid; and        a controller that controls the rotatable member in response to a measurement made by a sensor downhole.     
     
     
       30. The apparatus of  claim 29 , wherein the controller positions the rotatable member at different positions relative to the stationary member to produce pulses of different amplitudes. 
     
     
       31. The apparatus of  claim 30 , further comprising a motor coupled to the rotatable member. 
     
     
       32. The apparatus of  claim 31 , further comprising a processor that controls the motor. 
     
     
       33. The telemetry system of  claim 30 , further comprising a pressure sensor downhole for making the pressure measurement that controls the driver. 
     
     
       34. The telemetry system of  claim 30 , wherein the driver is a motor. 
     
     
       35. The telemetry system of  claim 34 , wherein the motor is directly coupled to the rotor. 
     
     
       36. The telemetry system of  claim 30 , wherein the driver controls the rotor to generate pressure pulses of different amplitudes. 
     
     
       37. A telemetry system, comprising:
   a drill string having a fluid flowing therethrough;        a pulser in a path of the fluid in the drill string, the pulser including a rotor proximate a stator, each of the rotor and stator having an opening to allow fluid flow therethrough; and        a driver controllably rotating the rotor in an open direction and a closed direction to obstruct flow of the fluid to generate pressure pulses in the fluid at more than one amplitude; and        a controller that controls the driver in response to a measurement made relating to the generated pulses.     
     
     
       38. A pulser system for generating pressure pulses in a downhole flowing fluid, comprising:
   a tubular string having a first member disposed therein, the first member having a first opening for flowing fluid therethrough;        a second member substantially coaxial with and rotatable relative to the first member proximate the first member, the second member having a second opening for flowing fluid therethrough; and        a motor coupled to the second member, the motor rotating the second member in a first direction and a second opposite direction to locate the second member at a predetermined position such that the second member at least partially obstructs the fluid flowing through the first opening thereby generating a pressure pulse, the predetermined position comprising (i)  a maximum open position, (ii) a minimum open position, and (iii) at least one intermediate position; and a controller that is configured to re-position the second member in fixed positions independent of flow and pressure conditions of the fluid flow.     
     
     
       39. The pulser system of  claim 38 , further comprising a pressure sensor to sense the amplitudes of pressure pulses for use by said controller. 
     
     
       40. The pulser system of  claim 41 , wherein said controller uses the pressure measurements of said sensor to change a pulse shape. 
     
     
       41. A telemetry method, comprising:
   providing a pulser in a fluid flow path downhole, the pulser having a rotor proximate a stator, each said stator and rotor having an opening to allow the fluid to flow therethrough; and        generating pressure pulses in the downhole fluid by controllably rotating the rotor to obstruct the flow of the fluid through the stator; and        taking a measurement of a characteristic of the pressure pulses downhole and controlling the rotor in response to the measurement.     
     
     
       42. The telemetry method of  claim 41 , wherein rotating the rotor further comprises positioning the rotor relative to the stator at difference positions to generate pressure pulses of different amplitudes.  
     
     
       43. The telemetry method of  claim 41  further comprising measuring a pressure downhole and controlling the rotor in response to the measured pressure to choose an amplitude of the generated pressure pulses. 
     
     
       44. The telemetry method of  claim 41  further comprising directly coupling the motor to the rotor. 
     
     
       45. The telemetry method of  claim 44  further comprising providing a controller downhole to control the motor. 
     
     
       46. A method of transmitting information from a downhole location to a surface location through a fluid stream in a wellbore, comprising:
   rotating a rotatable plate of a valve pulser in the wellbore relative to a stationary plate to different positions to obstruct fluid flow through the stationary plate to generate pressure pulses in the fluid stream; and        controlling the rotating of the rotatable plate to control a characteristic of the generated pressure pulses in response to a pressure measured downhole.     
     
     
       47. The method of  claim 46  wherein rotating the rotatable plate includes positioning the rotatable plate to generate pressure pulses of different amplitudes. 
     
     
       48. The method of  claim 46  further comprising providing a pressure transducer to measure the pressure downhole. 
     
     
       49. The method of  claim 46  further comprising providing a processor to control the characteristic of the pressure pulses. 
     
     
       50. The method of  claim 46  wherein a motor orients the rotatable plate in the different positions. 
     
     
       51. The method of  claim 50  further comprising connecting the motor directly to the rotatable plate. 
     
     
       52. The method of  claim 46  wherein the characteristic is pulse amplitude and the method further comprises adjusting the pulse amplitude of the pressure pulses. 
     
     
       53. The method of  claim 52  wherein adjusting the pulse amplitude includes adjusting the rotation of the rotatable plate in response to a pressure measured downhole. 
     
     
       54. The method of  claim 53  further comprising increasing the pulse amplitude of the generated pressure pulses when the measured pressure is less than a predetermined value and decreasing the pulse amplitude of the generated pressure pulses when the measured pressure is greater than the predetermined value. 
     
     
       55. The method of  claim 52  wherein adjusting the amplitude of the generated pressure pulses includes adjusting the amplitude based on a rate of increase of the generated pulses. 
     
     
       56. The method of  claim 46  wherein the characteristic of the generated pressure pulses is a pulse shape. 
     
     
       57. The method of  claim 56  wherein a processor controls the shape of the generated pulses to enhance surface detection. 
     
     
       58. The method of  claim 57  wherein the processor controls the characteristic of the pressure pulses independent of a flow condition of the fluid stream. 
     
     
       59. A shear valve pulser for transmitting information in the form of pressure pulses in a fluid stream downhole in a wellbore, comprising:
   a stationary plate having an opening that allows flow of the fluid therethrough;        a rotatable plate proximate the stationary plate adapted to rotate relative to the stationary plate to close and open the opening in the stationary plate to generate the pressure pulses in the fluid stream;        a motor coupled to the rotatable plate for controllably rotating the rotatable plate; and        a controller controlling the rotatable plate in response to a pressure measurement made downhole to position the rotating plate in different positions relative to the fixed plate to control the generated pressure pulses.     
     
     
       60. The shear valve pulser of  claim 59  wherein the controller rotates the rotatable plate to control amplitude of the generated pressure pulses. 
     
     
       61. The shear valve pulser of  claim 59  wherein the controller rotates the rotatable plate to control a shape of the generated pressure pulses. 
     
     
       62. The shear valve pulser of  claim 59  further comprising a pressure transducer that measures the pressure downhole. 
     
     
       63. The shear valve pulser of  claim 59  wherein the controller controls the generated pressure pulses during drilling of a wellbore. 
     
     
       64. The shear valve pulser of  claim 59  wherein the motor is directly coupled to the rotatable plate. 
     
     
       65. The shear valve pulser of  claim 59  wherein the controller controls the pressure pulses in response to sensing a rate of increase of amplitude of the pressure pulses.