Downlink path finding for controlling the trajectory while drilling a well

Patent metadata

Field	Value
Publication number	US-9970284-B2
Application number	US-201213584827-A
Country	US
Kind code	B2
Filing date	Aug 14, 2012
Priority date	Aug 14, 2012
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A method for drilling a well along a planned trajectory includes: receiving downhole data from a steerable drilling tool; processing the downhole data and creating a downlink path, the downlink path being recognizable by the steerable drilling tool; and controlling the trajectory of the steerable drilling tool based on the downlink path.

First claim

What is claimed is:

1. A method for drilling a well along a planned trajectory, the method comprising:
(a) rotating a rotary steerable system in a subterranean well to drill the well, the rotary steerable system requiring a specific control algorithm that makes changes to rotary steerable settings in a plurality of incremental steps less than a predetermined tolerance, the rotary steerable system only recognizing a predetermined set of downlink commands, the downlink commands controlling the rotary steerable system;
(b) receiving downhole data from the rotary steerable system while drilling the well in (a);
(c) processing the downhole data received in (b) in combination with the planned trajectory to compute a desired rotary steerable setting;
(d) comparing the desired rotary steerable setting with a current rotary steerable setting to compute a step change;
(e) comparing the step change with the predetermined tolerance;
(f) generating a downlink path when the step change computed in (d) exceeds the predetermined tolerance in (e), the downlink path consisting of a plurality of the downlink commands recognized in (a), the downlink path transitioning the rotary steerable system in incremental steps less than the predetermined tolerance from the current rotary steerable setting to the desired rotary steerable setting computed in (c); and
(g) sequentially downlinking the plurality of downlink commands that make up the downlink path generated in (f) to the rotary steerable system to change the rotary steerable setting from the current rotary steerable setting to the desired rotary steerable setting computed in (c) via the plurality of incremental steps, each of which is less than the predetermined tolerance to cause the rotary steerable system to control a trajectory of drilling along the planned trajectory.

2. The method of claim 1 , wherein generating the downlink path in (f) comprises:
identifying a differential downlink command from the plurality of downlink commands recognized in (a) and an absolute downlink command from the plurality of downlink commands recognized in (a);
(ii) selecting one of the differential downlink command and the absolute downlink command as one of the plurality of downlink commands in the downlink path;
(iii) repeating (i) and (ii) to iteratively select additional ones of the plurality of downlink commands in the downlink path until the step change computed in (d) is less than the predetermined tolerance in (e).

3. The method of claim 1 , wherein each of the plurality of downlink commands in the downlink path is expressed in Polar Coordinate System.

4. The method of claim 3 , wherein (f) further comprises calculating a distance between each of the plurality of downlink commands in the downlink path and the desired steering tool setting computed in (c) within the Polar Coordinate System.

5. The method of claim 1 , wherein each of the plurality of downlink commands in the downlink path is acceptable to the rotary steerable system.

6. The method of claim 1 , wherein generating the downlink path in (f) comprises using a Greedy Algorithm.

7. The method of claim 1 , wherein:
the rotary steerable setting comprises toolface and steering ratio; and
the predetermined tolerance comprises a toolface tolerance of six degrees and a steering ratio tolerance of 10 percent.

8. The method of claim 1 , wherein:
the rotary steerable setting comprises a toolface and a steering ratio; and
generating the downlink path in (f) further comprises:
(i) identifying a first plurality of candidate commands from among the predetermined set of downlink commands, wherein each of the first plurality of candidate commands is less than the predetermined tolerance from the current rotary steerable setting;
(ii) computing a distance in polar coordinates between each of the first plurality of candidate commands and the desired rotary steerable setting; and
(iii) selecting a candidate command among the first plurality of candidate commands having the smallest distance in (ii).

9. The method of claim 8 , wherein (f) further comprises
(iv) identifying a second plurality of candidate commands from among the predetermined set of downlink commands when the candidate command exceeds the predetermined tolerance compared to the desired rotary steerable setting, wherein each of the second plurality of candidate commands is less than the predetermined tolerance from the candidate command selected in (iii);
(v) computing a distance in polar coordinates between each of the candidate commands in the second plurality and the desired rotary steerable setting; and
(vi) selecting the candidate command having the smallest distance in (v).

10. A rotary steerable system for drilling a well along a planned trajectory, the system comprising a processor and a memory storing a program having instructions for causing the processor to perform the steps of:
(a) receiving a predetermined set of downlink commands, the downlink commands controlling the rotary steerable system, the rotary steerable system requiring a specific control algorithm that makes changes to rotary steerable settings in a plurality of incremental steps less than a predetermined tolerance, the rotary steerable system only recognizing said predetermined set of downlink commands;
(b) receiving downhole data from the rotary steerable system while drilling the well;
(c) processing the downhole data received in (b) in combination with the planned trajectory to compute a desired rotary steerable setting;
(d) comparing the desired rotary steerable setting with a current rotary steerable setting to compute a step change;
(e) comparing the step change with the predetermined tolerance;
(f) generating a downlink path when the step change computed in (d) exceeds the predetermined tolerance in (e), the downlink path consisting of a plurality of the downlink commands received in (a), the downlink path transitioning the rotary steerable system in incremental steps less than the predetermined tolerance from the current rotary steerable setting to the desired rotary steerable setting computed in (c); and
(g) sequentially downlinking the plurality of downlink commands that make up the downlink path generated in (f) to the rotary steerable system to change the rotary steerable setting from the current rotary steerable setting to the desired rotary steerable setting computed in (c) via the plurality of incremental steps, each of which is less than the predetermined tolerance to cause the rotary steerable system to control a trajectory of drilling along the planned trajectory.

11. The system of claim 10 , wherein generating the downlink path in (f) comprises:
identifying a differential downlink command from the plurality of downlink commands received in (a) and an absolute downlink command from the plurality of downlink commands received in (a);
(ii) selecting one of the differential downlink command and the absolute downlink command as one of the plurality of downlink commands in the downlink path;
(iii) repeating (i) and (ii) to iteratively select additional ones of the plurality of downlink commands in the downlink path until the step change computed in (d) is less than the predetermined tolerance in (e).

12. The system of claim 11 , wherein each of the plurality of downlink commands in the downlink path is expressed in Polar Coordinate System.

13. The method of claim 12 , wherein (f) further comprises calculating a distance between each of the plurality of downlink commands in the downlink path and the desired steering tool setting computed in (c) within the Polar Coordinate System.

14. The me

Assignees

• Tang Yuxin
• Li Dandan
• Guan Yanyan
• Schlumberger Technology Corp

Inventors

• Tang Yuxin
• Li Dandan
• Guan Yanyan

Classifications

• E21B7/04

  Directional drilling · CPC title

• E21B44/00 Primary

  Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions · CPC title