System and method for controlling drilling process

Patent metadata

Field	Value
Publication number	US-10400573-B2
Application number	US-201314765857-A
Country	US
Kind code	B2
Filing date	Feb 5, 2013
Priority date	Feb 5, 2013
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

Techniques for optimizing automated drilling processes are disclosed. Such techniques include modeling a formation and selecting a drilling trajectory in the formation. Measurements of rate of penetration (ROP), revolutions per minute (RPM), weight-on-bit (WOB) and torque-on-bit (TOB) of a drilling string at a position on the drilling trajectory in the formation are received. A functional relationship between depth of cut (DOC), WOB, and TOB for the modeled formation is determined. Operating constraints defining a safe operating envelope as a function of RPM and WOB along the selected drilling trajectory are determined, and an optimal RPM and WOB is determined based on operating constraints. A cost function of RPM and WOB is determined, and a path from current RPM and WOB to optimal RPM and WOB is determined based on the cost function.

First claim

What is claimed is:

1. A method for optimizing a drilling apparatus comprising:
using a processing system to:
model a formation;
select a drilling trajectory in the formation;
receive measurements indicative of rate of penetration (ROP), revolutions per minute (RPM), weight-on-bit (WOB) and torque-on-bit (TOB) of a drilling string at a position on the selected drilling trajectory in the formation;
determine a first functional relationship between depth-of-cut (DOC), WOB, and TOB for the modeled formation;
determine operating constraints defining a safe operating envelope as a function of RPM and WOB along the selected drilling trajectory;
determine a second functional relationship that defines a cost relationship as a function of RPM and WOB along the selected drilling trajectory;
determine an optimal RPM and an optimal WOB based on the operating constraints and the cost relationship;
determine a path from a current RPM and a current WOB to the optimal RPM and optimal WOB based upon the operating constraints and the cost relationship, wherein determining the path comprises:
identifying a no-go area within the safe operating envelope, the no-go area comprising a range of RPM and WOB values between the current RPM and current WOB and the determined optimal RPM and optimal WOB; and
defining the path such that the path avoids the no-go area; and

control a drill string of the drilling apparatus by adjusting RPM to the optimal RPM and adjusting WOB to the optimal WOB along the determined path.

2. The method of claim 1 wherein the safe operating envelope excludes the no-go area based on the formation model.

3. The method of claim 2 wherein the safe operating envelope excludes the no-go area based on received measurements of shocks and vibrations while drilling.

4. The method of claim 1 , wherein the first functional relationship between DOC, WOB, and TOB at the position on the drilling trajectory in the modeled formation comprises using a processing system to: obtain a plurality of segmentations by segmenting measurements according to a plurality of possible segments divided by change points each indicative of a change in an operating condition; for each segmentation, evaluate each of the segments by fitting input stream data corresponding to each segment to a model corresponding to each segment; for each segmentation, evaluate how well the model for each respective segment fits input data corresponding to each segment; and select at least one of the segmentations and the models corresponding to the segments of the selected segmentation(s) to determine a functional relationship between DOC, WOB, and TOB.

5. The method of claim 1 wherein the drilling string comprises a mud motor.

6. The method of claim 5 , further comprising using the processing system to: receive measurements indicative of a flow rate in the mud motor at the position on the drilling trajectory; determine a third functional relationship defining cost of drilling as a function of RPM, WOB and flow rate; and adjust RPM, WOB and flow rate at the position on the drilling trajectory to minimize the cost of drilling based on the third functional relationship.

7. A computer program product, comprising a non-transitory computer readable medium having a computer readable program code embodied therein, said computer readable program code containing instructions that, when executed by a computer, cause execution of the following steps:
model a formation;
select a drilling trajectory in the formation;
receive measurements indicative of rate of penetration (ROP), revolutions per minute (RPM), weight-on-bit (WOB) and torque-on-bit (TOB) of a drilling string at a position on the selected drilling trajectory in the formation;
determine a functional relationship between depth-of-cut (DOC), WOB, and TOB for the modeled formation;
determine operating constraints defining a safe operating envelope as a function of RPM and WOB along the selected drilling trajectory;
determine a functional relationship that defines a cost relationship as a function of RPM and WOB along the selected drilling trajectory;
determine an optimal RPM and an optimal WOB based on the operating constraints and the cost relationship;
determine a path from a current RPM and a current WOB to the optimal RPM and optimal WOB based upon the cost relationship, wherein determining the path comprises:
identifying a no-go area within the safe operating envelope, the no-go area comprising a range of RPM and WOB values between the current RPM and current WOB and the determined optimal RPM and optimal WOB; and
defining the path such that the path avoids the no-go area; and

control the drilling apparatus by adjusting RPM to the optimal RPM and adjusting WOB to the optimal WOB along the determined path.

8. The computer program product of claim 7 , wherein the safe operating envelope excludes the no-go area based on the formation model.

9. The computer program product of claim 7 , wherein the safe operating envelope excludes the no-go area based on received measurements of shocks and vibrations while drilling.

10. The computer program product of claim 7 , wherein determining the functional relationship between DOC, WOB, and TOB at the position on the drilling trajectory in the modeled formation comprises: obtain a plurality of segmentations by segmenting measurements according to a plurality of possible segments divided by change points each indicative of a change in an operating condition; for each segmentation, evaluate each of the segments by fitting input stream data corresponding to each segment to a model corresponding to each segment; for each segmentation, evaluate how well the model for each respective segment fits input data corresponding to each segment; and select at least one of the segmentations and the models corresponding to the segments of the selected segmentation(s) to determine a functional relationship between DOC, WOB, and TOB.

11. The computer program product of claim 7 , wherein the drilling string comprises a mud motor.

12. The computer program product of claim 11 , further comprising: receive measurements indicative of a flow rate in the mud motor at the position on the drilling trajectory; determine a functional relationship defining cost of drilling as a function of RPM, WOB and flow rate; and adjust RPM, WOB and flow rate at the position on the drilling trajectory to minimize the cost of drilling based on the functional relationship defining the cost of drilling as a function of RPM, WOB, and flow rate.

13. A drilling control apparatus, comprising:
a system for modeling a formation and selecting a drilling trajectory in the formation; a plurality of sensors that acquire measurements of depth-of-cut (DOC), revolutions per minute (RPM), weight-on-bit (WOB) and torque-on-bit (TOB) of a drilling string at a position on the drilling trajectory;
a processor; and
a memory including one or more non-transitory computer-readable media storing instructions that, when executed by the processor, cause the system to perform operations, the operations comprising:
determining a first functional relationship between depth of cut (DOC), weight-on-bit (WOB), and torque-on-bit (TOB) for the modeled formation;
determining operating constraints defining a safe operating envelope as a function of RPM and WOB along the selected drilling trajectory;
determining a second functional relationship that defines a cost relationship as a function of RPM and WOB along the selected drilling trajectory;
determining an optimal RPM and an optimal WOB based on the operating constraints and the cost relationship,
determining a path from

Assignees

• Schlumberger Technology Corp

Inventors

• Yang Cuili
• Belaskie James P
• Sanchez Flores Jose Luis
• Harmer Richard

Classifications

• 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

• G05B13/041

  in which a variable is automatically adjusted to optimise the performance · CPC title

• E21B4/02

  Fluid rotary type drives · CPC title

• E21B44/04 Primary

  in response to the torque of the drive {; Measuring drilling torque (E21B44/06 takes precedence; measuring stresses in a well bore pipe E21B47/007)} · CPC title

• E21B7/06

  Deflecting the direction of boreholes · CPC title