Method for drilling under rivers and other obstacles

• US 6,588,116 B2
• Filed: 08/06/2001
• Issued: 07/08/2003
• Est. Priority Date: 03/11/1999
• Status: Expired due to Term

• Current Assignee: Gyrodata Incorporated
• Original Assignee: Gyrodata Incorporated
• Inventors: Neubauer, Greg, Uttecht, Gary W., Dallas, Tim, Brosnahan, James F., Wright, Eric
• Primary Examiner(s): Bennett, G. Bradley
• Application Number:
  US09/923,034
• Publication Number:
  US 20020056201A1
• Time in Patent Office: 701 Days
• Field of Search: 333/01, 333/02, 333/03, 333/04, 333/13, 333/24, 731/525.4
• US Class Current: 33/313
• CPC Class Codes: E21B 47/022 of the borehole, e.g. using geomagnetism

Abstract

A method of drilling under barriers (rivers, highways and the like) is set out. The horizontal drilling system mounts a guidance tool on the end of the drill string just behind the drill bit. The guidance tool includes a pair of right angle accelero meters and a 3-axis mounted gyro. The gyro furnishes data in a plane at right angles to the z-axis. This defines four data streams to the CPU enabling determination of drill bit location and pathway.

Claims

1. A method of measuring location while forming a borehole with a drilling tool, the borehole crossing under an earth surface obstacle, the method comprising the steps of:

(a) moving an elongate sensor housing having an axis coincident therewith along the borehole to form measurements while drilling under the earth surface obstacle, the housing mounted for common movement with the drilling tool;

(b) positioning a rate gyro in said housing wherein said rate gyro forms output signals indicative of measured angular rate and taking a set of measurements to initialize the gyro at a first position;

(c) positioning in said housing first and second accelerometers at a right angle therebetween wherein said accelerometers define a transverse plane to the axis of said housing, and forming outputs indicative of values sensed thereby during movement between first and second positions in said borehole;

(d) forming subsequent data representative of the outputs of said rate gyro and said accelerometers during movement between said first and second positions along the borehole;

(e) forming subsequent accelerometer data representative of said accelerometer output signals, during movement between said first and second positions along the borehole; and

(f) converting said rate gyro data and said accelerometer data into a plot of the borehole.

2. The method of claim 1 wherein said housing is an elongate cylindrical housing and including the step of moving said housing along the borehole in a continuous motion between said first and second positions.

3. The method of claim 1 wherein said rate gyro is initially oriented to define an axis thereof coincident with the axis of said housing, and forming resolved X and Y components in said housing while moving between said first and second positions.

4. The method of claim 1 wherein said rate gyro is provided with first and second rate sensors at right angles for forming said rate gyro signals in X and Y axes with respect to the Z axis of the rate gyro, and further including the step of positioning the rate gyro so that the Z axis thereof coincides with said housing, and subsequently calculating azimuth from said rate gyro.

5. The method of claim 1 wherein said first and second positions are in a borehole inclined by a specified angle from the vertical.

6. A method of measuring along a borehole crossing under an earth surface obstruction, the method comprising the steps of:

(a) moving an elongate sensor housing having an axis coincident therewith along a borehole to measure first and second positions, wherein said first and second positions are at the earth'"'"'s surface and the borehole is substantially below the earth'"'"'s surface;

(b) positioning a rate gyro in said housing wherein said rate gyro forms output signals indicative of measured angular rate at first and second positions;

(c) positioning in said housing first and second accelerometers at a right angle therebetween wherein said accelerometers define a transverse plane to the axis of said housing, and forming outputs from said first and second accelerometers indicative of values sensed at first and second positions in said borehole and relative to a reference inclination;

(d) converting data representative of the outputs of said rate gyro and said accelerometers during movement between said first and second positions along the borehole to determine borehole inclination; and

(e) recording a plot of borehole inclination to form a plot between said first and second positions.

7. The method of claim 6 wherein said positions have different azimuth.

8. The method of claim 6 wherein said housing is suspended on an elongate wire line in a drill string and said wireline is moved to move said housing along a drilling borehole and movement of said housing is measured as a function of depth to form a record thereof.

9. The method of claim 6 wherein said housing is an elongate cylindrical housing and including the step of moving said housing along the borehole suspended from a cable and moving said housing in a continuous motion between said first and second positions to obtain azimuth between said first and second position.

10. The method of claim 9 wherein said rate gyro is initially oriented to define an axis thereof coincident with the axis of housing, and forming resolved X and Y components of movement of said rate gyro in said housing while moving between said first and second positions.

11. The method of claim 6 wherein said rate gyro is provided with first and second rate sensors at right angles for forming gyro rate output signals in X and Y axes with respect to the Z axis of the rate gyro, and further including the step of restoring the rate gyro so that the Z axis thereof coincides with s aid housing, and subsequently calculating borehole azimuth with respect to a reference azimuth measured with said rate gyro and with said 6 sensor housing stationary at said first position.

12. The method of claim 11 wherein said first and second positions are in a borehole inclined by a specified angle from the vertical.

13. A method of controlling an earth surface obstacle crossing borehole comprising the steps of:

(a) moving an elongate sensor housing having an axis coincident therewith along a borehole between first and second selected positions to form a control signal between said first and second positions;

(b) positioning a rate gyro in said housing wherein said rate gyro forms output signals indicative of measured angular rate between said first and second positions;

(c) positioning in said housing first and second accelerometers at a right angle therebetween wherein said accelerometers define a transverse plane to the axis of said housing, and forming outputs from said first and second accelerometers indicative of values sensed thereby during movement between first and second positions in said borehole with respect to a reference inclination at said first position;

(d) forming data representative of the outputs of said rate gyro with respect to a reference azimuth at said first position and said accelerometers during movement between said first and second positions along the borehole to determine borehole azimuth and inclination; and

(e) controlling borehole azimuth and inclination between said first and second positions.

14. The method of claim 13 wherein said housing is an elongate cylindrical housing and including the step of moving said housing along the borehole suspended from a cable and moving said housing between said first and second positions.

15. The method of claim 13 wherein said rate gyro is provided with first and second rate sensors at right angles for forming gyro rate output signals in X and Y axes with respect to the Z axis of the rate gyro, and further including the step of positioning the rate gyro so that the Z axis thereof coincides with said housing to direct said housing axis along said borehole, and determining azimuth from said rate gyro.

16. The method of claim 13 wherein said first and second positions are in a borehole inclined by a specified angle from the vertical.

17. The method of claim 13 wherein said rate gyro is initially oriented to define an axis thereof coincident with the axis of said housing, and forming resolved X and Y components of movements of said rate gyro in said housing while moving between said first and second positions.

18. The method of claim 17 wherein said housing is suspended on an elongate wireline in said borehole to move said housing along in said borehole and movement of said housing is measured as a function of depth to form a record thereof.

19. A method of guiding a river crossing borehole comprising the steps of:

(a) moving an elongate sensor housing along a borehole between first and second selected positions to survey the river crossing between said first and second positions as the borehole is being bored;

(b) positioning a rate gyro in said housing wherein said rate gyro forms orthogonal output signals indicative of measured angular rate between said first and second positions;

(c) positioning in said housing first and second accelerometers at a right angle therebetween wherein said accelerometers define a transverse plane to the axis of said housing;

(d) measuring a reference azimuth and a reference inclination at the start of the river crossing and computing and storing data representative of the outputs of said rate gyro relative to said reference azimuth and said accelerometers relative to said reference inclination between said first and second positions along the borehole; and

(e) converting the stored data into a plot of borehole azimuth between said first and second positions.

20. The method of claim 19 wherein said housing is an elongate cylindrical housing and including the step of moving said housing along the borehole in a continuous motion between said first and second positions.

21. The method of claim 19 including the step of creating a Z axis output from accelerometer data.

22. The method of claim 21 including the step of setting the reference horizontal plane relative to gravity.

23. The method of claim 21 including the step of projecting the gyro output data into a horizontal plane for measuring inclination from the gyro data.

24. A method of conducting a river crossing survey along a borehole comprising the steps of:

(a) moving an elongate sensor housing along a borehole between a start and second selected positions to form a survey between said first and second positions;

(b) positioning a rate gyro in said housing wherein said rate gyro forms orthogonal output signals indicative of measured angular rate between said start and second positions;

(c) positioning in said housing start and second accelerometers at a right angle therebetween wherein said accelerometers define a transverse plane to the axis of said housing;

(d) measuring gravity induced signals at the start position and determining therefrom a vector component describing the start position wherein the component includes well borehole inclination;

(e) measuring at the first position a vector component describing housing azimuth;

(f) moving the housing along the borehole from the start to a second position in the borehole;

(g) outputting data representing the inclination and azimuth, between start and positions;

(h) measuring a reference azimuth and a reference inclination at said start position and computing and storing data representative of the output of said rate gyro relative to azimuth;

(i) storing data representative of said accelerometers relative to inclination; and

(j) converting the stored data into a control signal for borehole azimuth between said start and second positions.

25. The method of claim 24 including the step of measuring linear travel of said housing along the borehole between the start and second positions.

26. The method of claim 24 including the step of measuring housing rotation as indicated by signals from said accelerometers.

27. The method of claim 24 including the step of measuring data from said rate gyro indicative of relative rotation of said housing in space from said start position.

28. A method of controlling drilling of a river crossing along a well borehole comprising the steps of:

(a) moving an elongate sensor housing along a well borehole from a start to a second position along the well borehole, the sensor mounted on a drilling tool used to drill the river crossing;

(b) measuring angular rate of the housing on movement from said start to the second position;

(c) placing first and second accelerometers at a right angle in said housing wherein said accelerometers define a transverse plane to axis of said housing;

(d) measuring gravity induced signals from said first and second accelerometers along the river crossing;

(e) determining the well borehole inclination;

(f) determining a vector component describing housing azimuth;

(g) moving the housing along the well borehole to a second position in the well borehole;

(h) forming data representing the inclination and azimuth; and

(i) converting the data into a plot of river crossing azimuth.

29. The method of claim 28 including the step of measuring linear travel of the housing along the well borehole.

30. The method of claim 28 including the step of measuring housing rotation as indicated by signals from the accelerometers.

31. A method of guiding drilling of a river crossing comprising the steps of:

positioning a sensor housing in a drill string;

positioning a gyro in the housing wherein the gyro forms orthogonal output signals responsive to gyro operation with housing movement along the river crossing;

positioning two orthogonal accelerometers in a plane traverse to the housing to form accelerometer output signals;

defining from the orthogonal accelerometer signals tool high side at a start time of the river crossing;

determining at the start time of the river crossing a position of the gyro as indicated by the output signals of the gyro; and

moving the housing along the river crossing from the start time to a second time; and

determining between the start and second times rotation of the housing around an axis along the well borehole in response to the output signals.