Method and system for controlling well bore pressure

• US 6,484,816 B1
• Filed: 01/26/2001
• Issued: 11/26/2002
• Est. Priority Date: 01/26/2001
• Status: Expired due to Term

• Current Assignee: Varco I/P Incorporated (NOV, Inc.)
• Original Assignee: Martin-Decker Totco, Inc. (NOV, Inc.)
• Inventors: Koederitz, William L.
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): HALFORD, BRIAN D
• Application Number:
  US09/770,594
• Time in Patent Office: 669 Days
• Field of Search: 175/24, 175/25, 175/38, 175/48, 175/66
• US Class Current: 175/25
• 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

Abstract

Methods and systems are provided for maintaining fluid pressure control of a well bore 30 drilled through a subterranean formation using a drilling rig 25 and a drill string 50, whereby a kick may be circulated out of the well bore and/or a kill fluid may be circulated into the well bore, at a kill rate that may be varied. A programmable controller 100 may be included to control execution of a circulation/kill procedure whereby a mud pump 90 and/or a well bore choke 70 may be regulated by the controller. One or more sensors may be interconnected with the controller to sense well bore pressure conditions and/or pumping conditions. Statistical process control techniques may also be employed to enhance process control by the controller. The controller 100 may further execute routine determinations of circulating kill pressures at selected kill rates. The controller may control components utilized in the circulation/kill procedure so as to maintain a substantially constant bottom hole pressure on the formation while executing the circulation/kill procedure.

Claims

1. A system for maintaining fluid pressure control of a well bore drilled through a subterranean formation using a drilling rig and a drill string having a through bore and positioned at least partially within the well bore, the system comprising:

a BOP to contain an annulus fluid pressure within an annulus of the well bore;

a drilling fluid choke in fluid communication with the annulus of the well bore;

a fluid pump for pumping the selected fluid at a benchmark selected fluid circulation rate through the drill string, then through the annulus of the well bore and substantially back to the drilling rig;

a drill pipe pressure sensor to sense a fluid pressure within the drill string; and

a programmable controller responsive to the drill pipe pressure sensor to control at least one of (a) the fluid pump to effect the fluid circulation rate, (b) the drilling fluid choke to control pressure in the annulus of the well bore, and (c) the BOP to control pressure in the annulus of the well bore, such that while pumping the selected fluid a bottom hole circulating fluid pressure remains substantially constant and at least as great as the bottom hole kick pressure, while also controlling an axial position of the drill string relative to the well bore.

2. The system for maintaining fluid pressure control of a well bore as defined in claim 1, further comprising:

a display for displaying as a function of time, one or more of (a) the circulating drill pipe kill pressure, (b) the annulus fluid pressure, (c) the bottom hole kick pressure, (d) the bottom hole circulating fluid pressure, (e) the selected kill flow rate, and (f) a volume of fluid pumped.

3. The system for maintaining fluid pressure control of a well bore as defined in claim 1, further comprising:

a well bore annulus pressure sensor to sense a fluid pressure in the annulus of the well bore.

4. The system for maintaining fluid pressure control of a well bore as defined in claim 1, further comprising:

an operator controller to override the programmable controller.

5. The system for maintaining fluid pressure control of a well bore as defined in claim 1, further comprising:

a controller programmer to alter the programmable controller.

6. The system for maintaining fluid pressure control of a well bore as defined in claim 1, further comprising:

a data introducer to input data into the programmable controller.

7. The system for maintaining fluid pressure control of a well bore as defined in claim 1, wherein the programmable controller further controls a draw-works to control the axial position of the drill string relative to the well bore.

8. A system for maintaining fluid pressure control of a well bore drilled through a subterranean formation using a drilling rig and a drill string having a through bore and positioned at least partially within the well bore, the system comprising:

a BOP to contain an annulus fluid pressure within an annulus of the well bore;

a drilling fluid choke in fluid communication with the annulus of the well bore;

a fluid pump for pumping the selected fluid at a benchmark selected fluid circulation rate through the drill string, then through the annulus of the well bore and substantially back to the drilling rig;

a drill pipe pressure sensor to sense a fluid pressure within the drill string;

a programmable controller responsive to the drill pipe pressure sensor to control at least one of (a) the fluid pump to effect the fluid circulation rate, (b) the drilling fluid choke to control pressure in the annulus of the well bore, and (c) the BOP to control pressure in the annulus of the well bore, such that while pumping the selected fluid a bottom hole circulating fluid pressure remains substantially constant and at least as great as the bottom hole kick pressure; and

a controller programmer to alter the programmable controller.

9. The system for maintaining fluid pressure control of a well bore as defined in claim 8, further comprising:

a display for displaying as a function of time, one or more of (a) the circulating drill pipe kill pressure, (b) the annulus fluid pressure, (c) the bottom hole kick pressure, (d) the bottom hole circulating fluid pressure, (e) the selected kill flow rate, and (f) a volume of fluid pumped.

10. The system for maintaining fluid pressure control of a well bore as defined in claim 8, further comprising:

a well bore annulus pressure sensor to sense a fluid pressure in the annulus of the well bore.

11. The system for maintaining fluid pressure control of a well bore as defined in claim 8, further comprising:

an operator controller to override the programmable controller.

12. The system for maintaining fluid pressure control of a well bore as defined in claim 8, further comprising:

a data introducer to input data into the programmable controller.

13. The system for maintaining fluid pressure control of a well bore as defined in claim 8, wherein the programmable controller further controls one or more of the draw-works and an axial position of the drill string relative to the well bore.

14. A method of maintaining fluid pressure control of a well bore drilled through a subterranean formation using a drilling rig and a drill string having a through bore and positioned at least partially within the well bore, the method comprising:

providing a BOP to contain an annulus fluid pressure within an annulus of the well bore;

providing a drilling fluid choke in fluid communication with the annulus of the well bore;

providing a fluid pump for pumping the selected fluid at a benchmark selected fluid circulation rate through the drill string, then through the annulus of the well bore and substantially back to the drilling rig;

sensing a fluid pressure within the drill string; and

in response to the sensed drill pipe fluid pressure, automatically controlling at least one of (a) the fluid pumps to effect the fluid circulation rate, (b) the drilling fluid choke to control pressure in the annulus of the well bore, and (c) the BOP to control pressure in the annulus of the well bore, such that while pumping the selected fluid a bottom hole circulating fluid pressure remains substantially constant and at least as great as the bottom hole kick pressure, while also automatically controlling an axial position of the drill string relative to the well bore.

15. The method as defined in claim 14, further comprising:

inputting data into the programmable controller.

16. The method as defined in claim 14, wherein the programmable controller further controls a draw works to control the axial position of the drill string relative to the well bore.

17. The method as defined in claim 14, further comprising:

variably adjusting a kill flow rate while substantially simultaneously controlling the drilling fluid choke to maintain the substantially constant bottom hole circulating fluid pressure.

18. The method as defined in claim 14, further comprising:

sensing fluid pressure in the annulus of the well bore substantially upstream of the drilling fluid choke.

19. The method as defined in claim 14, further comprising:

displaying, as a function fo time, one or more of (a) the circulating drill pipe kill pressure, (b) the annulus fluid pressure, (c) the bottom hole kick pressure, (d) the bottom hole circulating fluid pressure, (e) the selected kill flow rate, and (f) a volume of fluid pumped.

20. The method as defined in claim 14, further comprising:

sensing a first fluid pressure in at least one of the drill string and the well bore annulus;

sensing a second fluid pressure in at least one of the drill string and the well bore annulus;

using the programmable controller to selectively compare the first sensed fluid pressure with the second sensed fluid pressure to calculate a sensed pressure deviation;

comparing the sensed pressure deviation to a predetermined reference pressure deviation; and

generating an alarm signal when the sensed pressure deviation is greater than the predetermined reference pressure deviation.