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AssigneeBaker Hughes Incorporated
InventorsSven Krueger, Volker Krueger, Harald Grimmer, Roger Fincher, Larry Watkins, Peter Aronstam, Peter Fontana
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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.
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 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:
The method according to claim (14) wherein the operating parameter is selected from one of (i) flow rate, (ii) speed, and (iii) pressure.
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.
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.
The method according to claim (16) further comprising positioning the APD Device in a casing in the wellbore.
The method according to claim (14) wherein the operating parameter is set at the surface.
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;
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.
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;
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.
Dependencies are inferred from the claim text.