Claims
- 1. A method of making measurements made by at least one sensor mounted in a rotatable housing on a measurement-while-drilling (“MWD”) tool in a bottomhole assembly (BHA) having a drillbit thereon during the drilling of a borehole, the method comprising:
(a) locating the MWD tool in the borehole at a first depth and ceasing drilling operations; (b) determining a first rotational position of the at least one sensor at the first depth wherein an output of the sensor has a value substantially close to a maximum or a minimum, and taking a measurement thereat; (c) rotating the at least one sensor a plurality of discrete angles encompassing the first rotational position and taking additional measurements thereat, giving a plurality of additional measurements; and (d) using a processor on the tool for combining the first measurement and the plurality of additional measurements for determining a bias in the measurements made by the at least one sensor.
- 2. The method of claim 1 wherein the at least one sensor comprises at least one of (i) a two-axis gyroscope, (ii) a three-axis gyroscope, (iii) an accelerometer, and, (iv) a magnetometer.
- 3. The method of claim 1 wherein the discrete angles are selected from the group consisting of (i) 30 degrees, (ii) 60 degrees, (iii) −30 degrees, and, (iv) −60 degrees.
- 4. The method of claim 1 wherein rotating the at least one sensor further comprises using a reversible stepper motor operatively coupled to the housing through a slip clutch.
- 5. The method of claim 1 wherein using a processor for determining a bias in the at least one sensor further comprises fitting a sinusoid to outputs of the at least one sensor at the first rotational position and the plurality of additional measurements.
- 6. The method of claim 1 further comprising using the determined bias to obtain a corrected measurement of the at least one sensor.
- 7. The method of claim 6, wherein the at least one sensor comprises a two-axis gyroscope, the method further comprising determining a parameter of interest selected from the group consisting of (i) an azimuth with respect to the true north, (ii) toolface orientation with respect to the true north, iii) amplitude of measurements of the earth's rate vector for a two-axis gyroscope, (iv) amplitude of measurements of the earth's rate vector for a three-axis gyroscope, and (v) local apparent latitude for a three-axis gyroscope.
- 8. The method of claim 7 further comprising locking the housing having the at least one sensor in a fixed rotational position, moving the MWD tool to a second depth, and taking measurements with the at least one sensor during said movement of the MWD tool.
- 9. The method of claim 8 further comprising unlocking the housing having the at least one sensor and repeating steps (b)-(d) at said second depth to determine a bias in the at least one sensor and a value of the parameter of interest at the second depth.
- 10. The method of claim 9 wherein the second depth is greater than the first depth.
- 11. The method of claim 9 wherein the second depth is less than the first depth, the method further comprising tripping the tool out of the borehole.
- 12. The method of claim 8 further comprising using said measurements taken during movement of the tool along with the determined bias at the first depth to determined a value of the parameter of interest during said tool movement.
- 13. The method of claim 10 wherein the BHA further comprises a drilling liner carrying the drillbit, and wherein the MWD tool is retrievably conveyed within said drilling liner, the method further comprising using the drilling liner for drilling of the borehole.
- 14. A measurement-while-drilling (MWD) downhole assembly for use in drilling a borehole, comprising:
(a) a housing; (b) a sensor assembly rotatably mounted in the housing for providing signals relating to orientation of the tool; (c) a device for rotatably positioning and locking a drive shaft coupled to the housing at one of a plurality of angular positions; and (d) a processor in the tool, said processor combining signals from the sensor assembly taken at positions corresponding to a plurality of rotational positions at a first depth in the borehole to determine a bias present in the measurements made by the sensor assembly and determining therefrom corrected measurements, the processor further using said corrected measurements to determine a parameter of interest selected from the group consisting of (i) an azimuth with respect to the true north, (ii) toolface orientation with respect to the true north, iii) amplitude of measurements of the earth's rate vector for a two-axis gyroscope, (iv) amplitude of measurements of the earth's rate vector for a three-axis gyroscope, and (v) local apparent latitude for a three-axis gyroscope.
- 15. The MWD downhole assembly of claim 14 wherein the device for rotatably positioning and locking the drive shaft further comprises
A. a single reversible motor driving said drive shaft through a slip clutch; B. a lead screw adapted to rotate when said motor is operated; and, C. a locking mechanism actuated by said lead screw, said locking mechanism having a locked position wherein it engages said drive shaft and an unlocked position wherein it is operatively disengaged from said drive shaft.
- 16. The MWD downhole assembly of claim 14 further comprising:
A. a drilling liner carrying a drillbit thereon for drilling the borehole; B. an adapter tube within the drilling liner for supporting the housing; and C. a cable for retrieving the housing.
- 17. A method of recovery of hydrocarbons from a reservoir in a subterranean earth formation, the method comprising:
(a) drilling a first borehole into the reservoir; (b) obtaining information about the position of the first borehole at least within the reservoir; (c) lining the first wellbore with a casing; (d) drilling a second wellbore in proximity to the first borehole using a directional drilling device; (e) using a Gyro-MWD tool in the second wellbore to obtain information about the position and orientation of the second wellbore; and (f) controlling the directional drilling device in response to the obtained information about the location of the first borehole and the obtained information about the second wellbore so as to maintain a desired relation between the position of the first wellbore and the position of the second wellbore.
- 18. The method of claim 17 further comprising injecting a fluid selected from the group consisting of (i) water, (ii) CO2, (iii) steam, and recovering hydrocarbons in the producing wellbore through perforations in said casing.
- 19. A device for rotatably positioning and locking a drive shaft at one of a plurality of angular positions comprising:
(a) a single reversible motor driving said drive shaft through a slip clutch; (b) a lead screw adapted to rotate when said motor is operated; and, (c) a locking mechanism actuated by said lead screw, said locking mechanism having a locked position wherein it engages said drive shaft and an unlocked position wherein it is operatively disengaged from said drive shaft.
- 20. The device of claim 19 wherein the drive shaft has an annularly notched shoulder on an end distal from the slip clutch, said shoulder adapted to engage a rotational stop pin, thereby limiting drive shaft rotation to less than 360 degrees
- 21. The device of claim 20 wherein said stop pin and said shoulder are adapted to form an electrical circuit on contact with each other.
- 22. The device of claim 21 wherein a spur gear is fixedly attached to a motor drive shaft and operatively engaged with said lead screw, said spur gear adapted to rotate when said motor is operated.
- 23. The device of claim 22 wherein a locking disk is fixedly mounted on the drive shaft, said disk containing a plurality of locking holes located circumferentially disposed about a center of the disk.
- 24. The device of claim 23 wherein the locking mechanism further comprises:
(i) a trolley engaged with and slidably mounted on said lead screw; and (ii) a locking pin mounted on the trolley, said locking pin adapted to engage any of the plurality of locking holes on the locking disk.
- 25. The device of claim 24 further comprising a pair of electrical contacts adapted to make contact with the locking pin trolley when the locking pin is fully mated with the locking disk, said contacts and said locking pin trolley thereby completing an electrical circuit indicating that the locking pin is correctly seated.
- 26. The device of claim 23, wherein the locking mechanism further comprises a locking pin, hollow on one end, said hollow end threadably adapted to engage the lead screw and to slide over the lead screw in a telescoping manner when the lead screw is rotated, the end distal from the hollow end adapted to engage any of the plurality of locking holes on the locking disk.
- 27. The device of claim 22 wherein a locking disk is fixedly mounted on the drive shaft, said disk containing a plurality of locking pins located circumferentially disposed about a center of the disk
- 28. The device of claim 27 wherein the locking mechanism further comprises a trolley engaged with and slidably mounted on said lead screw, said trolley having a recess selected from a locking hole adapted to engage any of the plurality of locking pins on the locking disk.
- 29. The device of claims 28 further comprising a pair of electrical contacts adapted to make contact with the locking pin trolley when the locking pin is fully mated with the locking disk, said contacts and said locking pin trolley thereby completing an electrical circuit indicating that the locking pin is correctly seated.
- 30. The device of claim 27 wherein the locking mechanism further comprises a locking pin, hollow on one end, said hollow end threadably adapted to engage the lead screw and to slide over the lead screw in a telescoping manner when the lead screw is rotated, the end distal from the hollow end adapted to engage any of the plurality of locking pins on the locking disk.
- 31. The device of claim 23 wherein a locking disk is fixedly mounted on the drive shaft, said disk containing a plurality of locking pins located circumferentially disposed about a center of the disk.
- 32. The device of claim 31 wherein the locking mechanism further comprises a trolley engaged with and slidably mounted on said lead screw, said trolley adapted to engage the friction face of the locking disk.
- 33. The device of claim 31 wherein the locking mechanism further comprises:
a locking pin mounted on the trolley, said locking pin adapted to engage the friction face of the locking disk.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation-in-Part of U.S. patent application Ser. No. 09/204,908 filed on Dec. 3, 1998 (now U.S. Pat. No. *******) which has a priority date of Dec. 4, 1997 based upon U.S. Provisional Patent Application No. 60/067505. The present application also claims priority date of Aug. 29, 2000 based upon U.S. Provisional Patent Application No. 60/228578.
Provisional Applications (2)
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Number |
Date |
Country |
|
60067505 |
Dec 1997 |
US |
|
60228578 |
Aug 2000 |
US |
Divisions (1)
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Number |
Date |
Country |
Parent |
09669759 |
Sep 2000 |
US |
Child |
10341637 |
Jan 2003 |
US |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
09204908 |
Dec 1998 |
US |
Child |
09669759 |
Sep 2000 |
US |