Control systems and methods for active controlled bottomhole pressure systems
Methods and control systems are provided for a wellbore drilling system having an active differential pressure device (APD device) in fluid communication with a returning fluid. The APD Device creates a differential pressure across the device, which reduces the pressure below or downhole of the device. In embodiments, a control unit controls the APD Device to provide a selected pressure differential at a wellbore bottom, adjacent a casing shoe, in an intermediate wellbore location, or in a casing. In one arrangement, the control system is pre-set at the surface such that the APD Device provides a substantially constant pressure differential. In other arrangements, the control system measures one or more parameters (e.g., wellbore pressure, formation parameters, BHA parameters, etc.) and adjusts an operating parameter of the APD Device to provide a desired pressure differential. Devices such as an adjustable bypass can be used to control the APD Device.
1. A method of controlling pressure in a wellbore drilled in a formation using a drill string having a bottomhole assembly at an end of a tubing and wherein a drilling fluid supplied under pressure to the tubing returns to the surface (“the return fluid”), the method comprising:
(a) providing an Active Pressure Differential Device (“APD Device) in the return fluid; and
(b) controlling the APD Device to control a pressure relative to a formation pressure parameter at a selected location in the wellbore.
2. The method of claim 1 , further comprising controlling the APD Device in response to at least one determined parameter relating to a selected fluid in the wellbore.
3. The method according to claim 2 wherein the selected fluid is drilling fluid and the at least one determined parameter is selected from one of (i) flow rate, (ii) density, (iii) temperature, and (iv) pressure.
4. The method of claim 1 , further comprising controlling the APD Device in response to a determined pressure differential between an inlet of the APD Device and an outlet of the APD Device using a control unit.
5. The method of claim 4 , wherein the APD Device is controlled to provide a pre-determined pressure differential between the APD Device inlet and outlet.
6. The method according to claim 1 further comprising determining at least one formation parameter, and wherein the APD device is further controlled in response to the at least one formation parameter.
7. The method according to claim 6 wherein the formation parameter is selected from one of (i) pore pressure, (ii) fracture pressure, (iii) a geophysical property, (iv) a petrophysical property, and (v) collapse pressure.
8. The method according to claim 1 further comprising determining at least one drilling parameter, and wherein the APD device is further controlled in response to the at least one drilling parameter.
9. The method according to claim 8 wherein the drilling parameter is selected from one of (i) ROP, (ii) vibration, and (iii) flow rate.
10. The method of claim 1 , wherein the selected location in the wellbore at which the pressure is controlled is one of (i) at the wellbore bottom, (ii) proximate to a casing shoe, (iii) at an open wellbore section uphole of the bottomhole assembly; and (iv) in a casing.
11. The method of claim 1 further comprising: controlling the APD Device in response to the determined pressure differential between the formation pressure parameter and a pressure of the drilling fluid.
12. The method of claim 1 , wherein the formation pressure parameter is selected from one of (i) pore pressure, (ii) collapse pressure, and (iii) fracture pressure.
13. The method of claim 1 further comprising: providing at least a second APD Device in the return fluid; and controlling the APD Device and the second APD Device to provide a selected pressure profile in the wellbore.
14. A method of controlling pressure in a wellbore drilled in a formation using a drill string having a bottomhole assembly at an end of a tubing and wherein a drilling fluid supplied under pressure to the tubing returns to the surface (“the return fluid”), the method comprising:
(a) providing an Active Pressure Differential Device (“APD Device”) for controlling pressure in the wellbore, the APD Device having at least one operating parameter settable to control a pressure differential provided by the APD Device;
(b) setting the at least one operating parameter for the APD Device such that the APD Device will cause a selected pressure differential in the return fluid;
(c) positioning the APD Device in the return fluid in the wellbore; and
(d) operating the APD Device to provide the selected pressure differential in the return fluid.
15. The method according to claim ( 14 ) wherein the operating parameter is selected from one of (i) flow rate, (ii) speed, and (iii) pressure.
16. The method according to claim ( 14 ) further comprising determining a formation pressure parameter relating to the formation at a casing shoe in the wellbore, and wherein the operating parameter is selected to provide a specified pressure differential with respect to the determined formation pressure parameter.
17. The method according to claim ( 16 ) wherein the formation pressure parameter is selected from one of (i) pore pressure, (ii) collapse pressure, and (iii) fracture pressure.
18. The method according to claim ( 16 ) further comprising positioning the APD Device in a casing in the wellbore.
19. The method according to claim ( 14 ) wherein the operating parameter is set at the surface.
20. The method according to claim ( 14 ) further comprising determining a pressure differential between an inlet of the APD Device and an outlet of the APD Device; and setting the operating parameter of the APD Device in response to the determined pressure differential.
21. The method according to claim ( 14 ) further comprising determining a pore pressure proximate to a casing shoe and setting the operating parameter to provide a wellbore pressure at the casing shoe that provides a condition selected from one of (i) an over-balance, (ii) an at-balance, and (iii) and an under-balance.
22. The method according to claim ( 14 ) wherein the at least one operating parameter can be set by adjusting an adjustable fluid bypass that diverts fluid around one of (i) the APD Device; and (ii) a motor associated with the APD Device.
23. The method according to claim ( 14 ) further comprising controlling the APD Device with a control unit adapted to adjust the operating parameter of the APD Device in response to at least one determined parameter.