Real-time trajectory estimation with multi-station analysis

• US 10,246,988 B2
• Filed: 09/28/2016
• Issued: 04/02/2019
• Est. Priority Date: 09/28/2015
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Wang, Shuoqin, Sorenson, Logan D., Nguyen, Hung, Chang, David
• Primary Examiner(s): Barbee, Manuel L
• Assistant Examiner(s): Nimox, Raymond L
• Application Number:
  US15/279,390
• Publication Number:
  US 20170314384A1
• Time in Patent Office: 916 Days
• CPC Class Codes: E21B 47/022 of the borehole, e.g. using geomagnetism
• CPC Class Codes: E21B 47/024 of devices in the borehole determining slope or direction of the borehole E21B47/022
• CPC Class Codes: E21B 7/04 Directional drilling
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems

Abstract

Described is a system for position estimation. A set of raw sensor outputs are acquired from a sensor of a platform. The set of raw sensor outputs are stored in non-transitory memory. A set of optimized sensor measurements is generated by deducing errors in the raw sensor outputs using an unconstrained optimization algorithm. The system determines a position of the platform based on the set of optimized sensor measurements.

Claims

1. A system for position estimation, the system comprising:

a measurement-while-drilling (MWD) tool;

at least one accelerometer sensor and at least one magnetometer sensor positioned on the MWD tool;

one or more processors in communication with the at least one accelerometer sensor and the at least one magnetometer sensor and a non-transitory computer-readable medium having executable instructions encoded thereon such that when executed, the one or more processors perform operations of;

acquiring a set of raw sensor outputs from the at least one accelerometer sensor and the at least one magnetometer sensor on the MWD tool and storing the set of raw sensor outputs in non-transitory memory;

generating a set of optimized sensor measurements by deducing errors in the raw sensor outputs using an unconstrained optimization algorithm, wherein the unconstrained optimization algorithm minimizes an objective function that is a product of sums of differences squared between the raw sensor outputs and theoretical values;

determining a position of the MWD tool based on the set of optimized sensor measurements; and

causing a bottom hole assembly to drill based on the position of the MWD tool.

2. The system as set forth in claim 1, wherein the MWD tool is located in a drilling well of a drilling site.

3. The system as set forth in claim 2, wherein the one or more processors further perform operations of:

determining drilling attitudes at all drilling sites using the set of optimized sensor measurements; and

determining a drilling trajectory at all drilling sites using the determined drilling attitudes.

4. The system as set forth in claim 1, wherein the unconstrained optimization algorithm is used to deduce at least one of magnetometer sensor errors, accelerometer sensor errors, and gyroscope sensor errors.

5. The system as set forth in claim 2, wherein the unconstrained optimization algorithm minimizes the following objective function:

6. The system as set forth in claim 2, wherein if accelerometer sensors errors are relatively small compared with magnetometer sensor errors, then the unconstrained optimization algorithm minimizes the following objective function:

7. The system as set forth in claim 2, wherein if gyroscope sensor errors are available, then the unconstrained optimization algorithm minimizes the following objective function:

ƒ

_obj=Σ

_i=1^N(ER−

_l)²,

where ER is a measured earth rotation rate, is a theoretical earth rotation rate, and N is the number of times the drilling site has been surveyed.

8. The system as set forth in claim 2, wherein a drilling trajectory is determined from the set of optimized sensor measurements, and wherein the drilling trajectory is described by a set of points having coordinates on the trajectory of the curvature, wherein the coordinates of the set of points are determined according to the following:

9. A computer-implemented method for position estimation, comprising:

an act of causing one or more processors in communication with at least one accelerometer sensor and at least one magnetometer sensor to execute instructions stored on a non-transitory memory such that upon execution, the one or more processors perform operations of;

acquiring a set of raw sensor outputs from the at least one accelerometer sensor and the at least one magnetometer sensor on a measurement-while-drilling (MWD) tool and storing the set of raw sensor outputs in non-transitory memory;

generating a set of optimized sensor measurements by deducing errors in the raw sensor outputs using an unconstrained optimization algorithm, wherein the unconstrained optimization algorithm minimizes an objective function that is a product of sums of differences squared between the raw sensor outputs and theoretical values;

determining a position of the MWD tool based on the set of optimized sensor measurements; and

causing a bottom hole assembly to drill based on the position of the MWD tool.

10. The method as set forth in claim 9, wherein the MWD tool is located in a drilling well of a drilling site.

11. The method as set forth in claim 10, wherein the one or more processors further perform operations of:

determining drilling attitudes at all drilling sites using the set of optimized sensor measurements; and

determining a drilling trajectory at all drilling sites using the determined drilling attitudes.

12. The method as set forth in claim 9, wherein the unconstrained optimization algorithm is used to deduce at least one of magnetometer sensor errors, accelerometer sensor errors, and gyroscope sensor errors.

13. The method as set forth in claim 10, wherein the unconstrained optimization algorithm minimizes the following objective function:

14. The method as set forth in claim 10, wherein if accelerometer sensors errors are relatively small compared with magnetometer sensor errors, then the unconstrained optimization algorithm minimizes the following objective function:

15. The method as set forth in claim 10, wherein if gyroscope sensor errors are available, then the unconstrained optimization algorithm minimizes the following objective function:

ƒ

_obj=Σ

_i=1^N(ER−

_l)²,

where ER is a measured earth rotation rate, is a theoretical earth rotation rate, and N is the number of times the drilling site has been surveyed.

16. The method as set forth in claim 10, wherein a drilling trajectory is determined from the set of optimized sensor measurements, and wherein the drilling trajectory is described by a set of points having coordinates on the trajectory of the curvature, wherein the coordinates of the set of points are determined according to the following:

17. A computer program product for position estimation, the computer program product comprising:

computer-readable instructions stored on a non-transitory computer-readable medium that are executable by a computer having one or more processors in communication with at least one accelerometer sensor and at least one magnetometer sensor for causing the processor to perform operations of;

acquiring a set of raw sensor outputs from the at least one accelerometer sensor and the at least one magnetometer sensor on a measurement-while-drilling (MWD) tool and storing the set of raw sensor outputs in non-transitory memory;

generating a set of optimized sensor measurements by deducing errors in the raw sensor outputs using an unconstrained optimization algorithm, wherein the unconstrained optimization algorithm minimizes an objective function that is a product of sums of differences squared between the raw sensor outputs and theoretical values;

determining a position of the MWD tool based on the set of optimized sensor measurements; and

causing a bottom hole assembly to drill based on the position of the MWD tool.

18. The computer program product as set forth in claim 17, wherein the MWD tool is located in a drilling well of a drilling site, and wherein the computer program product further comprises instructions for causing the one or more processors to perform operations of:

determining drilling attitudes at all drilling sites using the set of optimized sensor measurements; and

determining a drilling trajectory at all drilling sites using the determined drilling attitudes.

19. The computer program as set forth in claim 17, wherein the unconstrained optimization algorithm minimizes the following objective function:

20. The computer program as set forth in claim 17, wherein if accelerometer sensors errors are relatively small compared with magnetometer sensor errors, then the unconstrained optimization algorithm minimizes the following objective function:

21. The computer program as set forth in claim 17, wherein if gyroscope sensor errors are available, then the unconstrained optimization algorithm minimizes the following objective function:

ƒ

_obj=Σ

_i=1^N(ER−

_l)²,

where ER is a measured earth rotation rate, is a theoretical earth rotation rate, and N is the number of times a drilling site has been surveyed.

22. The computer program as set forth in claim 17, wherein a drilling trajectory is determined from the set of optimized sensor measurements, and wherein the drilling trajectory is described by a set of points having coordinates on the trajectory of the curvature, wherein the coordinates of the set of points are determined according to the following: