Method and apparatus for automated drilling rig sheave friction calibration

Patent metadata

Field	Value
Publication number	US-2018238162-A1
Application number	US-201715436475-A
Country	US
Kind code	A1
Filing date	Feb 17, 2017
Priority date	Feb 17, 2017
Publication date	Aug 23, 2018
Grant date	—

Abstract

A method and autodriller for monitoring hookload in a well drilling system that measures raw hookload; determines a velocity of a travelling block; holds the travelling block in a non-lowering state for a first period of time; lowers the travelling block for a second period of time; calculates contribution to hookload of a component linear in the block velocity; calculates contribution to hookload of a component linear in a direction (sign) in the block velocity; and corrects measured raw hookload by the calculated contributions.

First claim

What is claimed is:

1 . A method for monitoring hookload in a well drilling system, the method comprising:
measuring raw hookload; determining a velocity of a travelling block; holding the travelling block in a non-lowering state for a first period of time; lowering the travelling block for a second period of time; calculating contribution to hookload of a component linear in the block velocity; calculating contribution to hookload of a component linear in a direction (sign) in the block velocity; and correcting measured raw hookload by the calculated contributions.

2 . A method for monitoring hookload in a well drilling system as claimed in claim 1 , wherein the first period of time is between about 1 second and about 120 seconds in length, and wherein the second period of time is between about 1 second and about 20 seconds in length.

3 . A method for monitoring hookload in a well drilling system as claimed in claim 1 , wherein the calculating contribution to hookload of a component linear in the block velocity and the calculating contribution to hookload of a component linear in a direction (sign) in the block velocity comprise using linear regression.

4 . A method for monitoring hookload in a well drilling system as claimed in claim 1 , wherein the correcting measured raw hookload by the calculated contributions comprises subtracting the calculated contributions from the measured raw hookload.

5 . A method for monitoring hookload in a well drilling system as claimed in claim 1 , further comprises preventing the weigh-on-bit from exceeding a preset limit during said lowering the travelling block for a second period of time.

6 . A method for monitoring hookload in a well drilling system as claimed in claim 1 , further comprises preventing the weigh-on-bit from decreasing below a preset limit during said holding the travelling block in a steady position for a first period of time.

7 . A method for monitoring hookload in a well drilling system as claimed in claim 1 , further comprising repeating the steps of holding the travelling block and lowering the travelling block during a calibration period.

8 . A method for monitoring hookload in a well drilling system as claimed in claim 7 , wherein the first and second periods of time are different when the steps of holding the travelling block and lowering the travelling block are repeated.

9 . A method for monitoring hookload in a well drilling system as claimed in claim 7 , wherein the repeated first and second periods of time each comprise a mixture of full amplitude fast and slow block movements, together with some shorter movements, whereby a variety of travelling block velocity profiles are used when the steps of holding the travelling block and lowering the travelling block are repeated.

10 . A method for monitoring hookload in a well drilling system as claimed in claim 7 , wherein the calibration period is between about 5 minutes and about 45 minutes in length.

11 . An autodriller for monitoring hookload in a well drilling system, the autodriller comprising:
a hookload receptor that receives a signal corresponding to raw hookload; a travelling block receptor that receives a signal corresponding to travelling block velocity; a processor; a non-transitory storage medium; and a set of computer readable instructions stored in the non-transitory storage medium,
wherein when the instructions are executed by the processor allow the autodriller to:
command the travelling block to hold not lower for a first period of time;
command the travelling block to lower for a second period of time;
calculate contribution to hookload of a component linear in the block velocity;
calculate contribution to hookload of a component linear in a direction (sign) in the block velocity; and
correct measured raw hookload by the calculated contributions.

12 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 11 , wherein the first period of time is between about 1 second and about 120 seconds in length, and wherein the second period of time is between about 1 second and about 20 seconds in length.

13 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 11 , wherein the calculating contribution to hookload of a component linear in the block velocity and the calculating contribution to hookload of a component linear in a direction (sign) in the block velocity comprise using linear regression.

14 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 11 , wherein the correcting measured raw hookload by the calculated contributions comprises subtracting the calculated contributions from the measured raw hookload.

15 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 11 , wherein when the instructions are executed by the processor the instructions further allow the autodriller to prevent the weigh-on-bit from exceeding a preset limit while the travelling block is commanded to lower for the second period of time.

16 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 11 , wherein when the instructions are executed by the processor the instructions further allow the autodriller to prevent the weigh-on-bit from decreasing below a preset limit while the travelling block is commanded to hold a steady position for the first period of time

17 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 11 , wherein when the instructions are executed by the processor the instructions further allow the autodriller to repeatedly command the travelling block to hold in a steady position and repeatedly command the travelling block to lower during a calibration period.

18 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 17 , wherein the first and second periods of time are different when the command of the travelling block to hold in a steady position for a first period of time is repeated and the command of the travelling block to lower for a second period of time is repeated.

19 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 17 , wherein the repeated first and second periods of time each comprise a mixture of full amplitude fast and slow block movements, together with some shorter movements, whereby a variety of travelling block velocity profiles are used when the steps of holding the travelling block and lowering the travelling block are repeated.

20 . An autodriller for monitoring hookload in a well drilling system, as claimed in claim 17 , wherein the calibration period is between about 5 minutes and about 45 minutes in length.

Assignees

• Schlumberger Technology Corp

Inventors

• Jeffryes Benjamin Peter

Classifications

• G01L25/00

  Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency · CPC title

• E21B44/02

  Automatic control of the tool feed ({E21B44/005,} E21B44/10 take precedence) · CPC title

• G01L5/04 Primary

  for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands {(G01L5/0004 takes precedence)} · CPC title

• E21B19/08 Primary

  Apparatus for feeding the rods or cables (E21B19/22 takes precedence; automatic feed E21B44/02); Apparatus for increasing or decreasing the pressure on the drilling tool; Apparatus for counterbalancing the weight of the rods · 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