Methods and systems for drilling

• US 9,879,490 B2
• Filed: 10/11/2012
• Issued: 01/30/2018
• Est. Priority Date: 04/12/2010
• Status: Active Grant

• Current Assignee: Shell USA Incorporated (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Edbury, David Alston, Guerrero, Jose Victor, MacDonald, Duncan Charles, Rogers, James Bryon, Sitton, Donald Ray, Norman, Jason B.
• Primary Examiner(s): Harcourt, Brad
• Application Number:
  US13/649,374
• Publication Number:
  US 20130277111A1
• Time in Patent Office: 1,937 Days
• Field of Search: 175 24, 175 27, 175 38, 175 48
• CPC Class Codes: E21B 21/01 Arrangements for handling drilling fluids or cuttings outside the borehole, e.g. mud boxes
• CPC Class Codes: E21B 21/08 Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure valve arrangements therefor E21B21/10
• CPC Class Codes: E21B 37/00 Methods or apparatus for cleaning boreholes or wells E21B21/00 takes precedence
• CPC Class Codes: E21B 44/00 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 Class Codes: E21B 44/02 Automatic control of the tool feed E21B44/005, E21B44/10 take precedence
• CPC Class Codes: E21B 44/06 in response to the flow or pressure of the motive fluid of the drive
• CPC Class Codes: E21B 47/00 Survey of boreholes or wells monitoring pressure or flow of drilling fluid E21B21/08
• CPC Class Codes: E21B 47/003 Determining well or borehole volumes
• CPC Class Codes: E21B 49/005 Testing the nature of borehole walls or the formation by using drilling mud or cutting data
• CPC Class Codes: E21B 7/06 Deflecting the direction of boreholes

Abstract

A method of automatically placing a drill bit used to form an opening in a subsurface formation on a bottom of the opening being formed comprises a) increasing a flow rate in a drill string to a target flow; b) controlling a flow rate of fluid into the drill string to be substantially the same as a flowrate of fluid out of the opening; c) allowing a fluid pressure to reach a relatively steady state; and d) automatically moving the drill bit toward the bottom of the opening at a selected rate of advance until an increase in measured differential pressure indicates that the drill bit is at the bottom of the opening.

Claims

1. A method of automatically placing a drill bit used to form an opening in a subsurface formation on a bottom of the opening being formed, comprising:

a) increasing a flow rate in a drill string to a target flow;

b) controlling a flow rate of fluid into the drill string to be substantially the same as a flow rate of fluid out of the opening;

c) allowing a fluid pressure to reach a relatively steady state;

d) automatically moving the drill bit toward the bottom of the opening at a selected rate of advance until an increase in measured differential pressure indicates that the drill bit is at the bottom of the opening; and

e) backing the drill bit off the bottom of the opening if the flow rate of fluid into the drill pipe is not substantially the same as the flow rate of fluid out of the opening.

2. The method of claim 1, further comprising advancing the drill bit in the opening while the drill is on the bottom of the opening.

3. The method of claim 1 wherein controlling the flow rate of fluid into the drill string to be substantially the same as a flow rate of fluid out of the opening comprises controlling at least one of the flow rates such that the difference in flow rate into the drill string and out of the drill string is within user set point limits.

4. The method of claim 1 wherein automatically moving the drill bit toward the bottom of the opening comprises rotating the drill string.

5. The method of claim 4 wherein drill string rotation is commenced before the flow rate is increased to the target flow.

6. The method of claim 4 wherein drill string rotation is commenced before the flow rate is increased to the target flow such that pressure is reduced when mud flow is recommenced in the annulus.

7. The method of claim 1 wherein allowing the fluid pressure to reach a relatively steady state comprises allowing the standpipe pressure to be in a steady state within predetermined set point limits.

8. The method of claim 1 wherein increasing a flow rate in a drill string to a target flow comprises ramping up the flow rate at a predetermined rate.