Dynamic annular pressure control apparatus and method

• US 20030196804A1
• Filed: 02/18/2003
• Published: 10/23/2003
• Est. Priority Date: 02/20/2002
• Status: Active Grant

• Current Assignee: Smith International Incorporated (SLB)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Riet, Egbert Jan van
• Granted Patent: US 6,904,981 B2
• Time in Patent Office: Days
• US Class Current: 166/267
• 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 21/106 Valve arrangements outside the borehole, e.g. kelly valves valves specifically for maintaining circulation of drilling fluid while connecting or disconnecting tubular joints E21B21/019
• 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

Abstract

A system and method for controlling formation pressures during drilling of a subterranean formation utilizing a selectively fluid backpressure system in which fluid is pumped down the drilling fluid return system in response to detected borehole pressures. A pressure monitoring system is further provided to monitor detected borehole pressures, model expected borehole pressures for further drilling and control the fluid backpressure system.

Claims

1. A system for controlling formation pressure during the drilling of a subterranean formation, comprising:

a drill string extending into a borehole, the drill string including a bottom hole assembly, the bottom hole assembly comprising, drill bit, sensors, and a telemetry system capable of receiving and transmitting data, including sensor data, said sensor data including at least pressure and temperature data;

a surface telemetry system for receiving data and transmitting commands to the bottom hole assembly;

a primary pump for selectively pumping a drilling fluid from a drilling fluid source, through said drill string, out said drill bit and into an annular space created as said drill string penetrates the formation;

a fluid discharge conduit in fluid communication with said annular space for discharging said drilling fluid to a reservoir to clean said drilling fluid for reuse;

a fluid backpressure system connected to said fluid discharge conduit;

said fluid backpressure system comprised of a flow meter, a fluid choke, a backpressure pump, a fluid source, whereby said backpressure pump may be selectively activated to increase annular space drilling fluid pressure.

2. The system of claim 1, further including a pressure monitoring system, capable of receiving drilling operational data, said drilling operational data including drill string weight on bit, drill string torque on bit, drilling fluid weight, drilling fluid volume, primary and backpressure pump pressures, drilling fluid flow rates, drill string rate of penetration, drill string rotation rate, and sensor data transmitted by said bottom hole assembly.

3. The system of claim 2, wherein said pressure monitoring system utilizes said drilling operational data to

monitor existing said annular space pressures during drilling operations;

model borehole expected pressures for continued drilling; and

control said primary pump and fluid backpressure system in response to existing annular pressures and borehole expected pressures.

4. The system of claim 3, wherein said pressure monitoring system further includes communication means, processing means, and control means for controlling said primary pump and fluid backpressure system.

5. The system of claim 1, wherein said fluid backpressure system fluid source is said drilling fluid source.

6. The system of claim 1, wherein said fluid backpressure system fluid source is said fluid discharge outlet.

7. A method for controlling formation pressure during the drilling of a subterranean formation, the steps comprising:

deploying a drill string extending into a borehole, the drill string including a bottom hole assembly, the bottom hole assembly comprising, drill bit, sensors, and a telemetry system capable of receiving and transmitting data, including sensor data, said sensor data including at least pressure and temperature data;

providing a surface telemetry system for receiving data and transmitting commands to said bottom hole assembly;

selectively pumping a drilling fluid utilizing a primary pump from a drilling fluid source, through said drill string, out said drill bit and into an annular space created as said drill string penetrates the formation;

providing a fluid discharge conduit in fluid communication with said annular space for discharging said drilling fluid to a reservoir to clean said drilling fluid for reuse;

selectively increasing annular space drilling fluid pressure utilizing a fluid backpressure system connected to said fluid discharge conduit;

said fluid backpressure system comprised of a flow meter, a fluid choke, a backpressure pump, and a fluid source.

8. The method of claim 7, further providing a pressure monitoring system for receiving drilling operational data, said drilling operational data including drill string weight on bit, drill string torque on bit, drilling fluid weight, drilling fluid volume, primary and backpressure pump pressures, drilling fluid flow rates, drill string rate of penetration, drill string rotation rate, and sensor data transmitted by said bottom hole assembly.

9. The method of claim 8, wherein said pressure monitoring system, utilizing said drilling operational data, further

monitors existing said annular space pressures during drilling operations;

models borehole expected pressures for continued drilling; and

controls said primary pump and fluid backpressure system in response to existing annular pressures and borehole expected pressures.

10. The method of claim 9, wherein said pressure monitoring system further includes communication means, processing means, and control means for controlling said primary pump and fluid backpressure system.

11. The method of claim 7, wherein said fluid backpressure system fluid source is said drilling fluid source.

12. The method of claim 7, wherein said fluid backpressure system fluid source is said fluid discharge outlet.