Elastic pipe control with managed pressure drilling
First Claim
1. A method comprising:
- obtaining at least one fluid property of an input fluid to a well and of a return fluid from the well;
calculating an elasticity parameter of a drill string within the well based at least in part on the at least one fluid property;
calculating a wellhead setpoint pressure that results in a predetermined downhole pressure at a predetermined location in the well, the calculation based at least in part on the elasticity parameter and the at least one fluid property; and
controllably regulating the flow of the return fluid to maintain the calculated wellhead setpoint pressure.
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Accused Products
Abstract
Disclosed embodiments include systems and methods for improving the accuracy of bottom hole pressure control. One example embodiment includes a torque and drag model that calculates the elasticity of the drill string, which is included in a managed pressure drilling control system. The addition of the torque and drag calculations provide more accurate surge/swab effect calculations based on pipe movement corrected for elasticity effects. The results of these calculations will be used in a real-time hydraulics model to determine a setpoint pressure which will be utilized by a MPD choke system. Further, the real-time torque and drag models are calibrated to actual hole conditions in real-time using survey, temperature, pressure and downhole tool data to calculate friction factors in a wellbore.
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Citations
20 Claims
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1. A method comprising:
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obtaining at least one fluid property of an input fluid to a well and of a return fluid from the well; calculating an elasticity parameter of a drill string within the well based at least in part on the at least one fluid property; calculating a wellhead setpoint pressure that results in a predetermined downhole pressure at a predetermined location in the well, the calculation based at least in part on the elasticity parameter and the at least one fluid property; and controllably regulating the flow of the return fluid to maintain the calculated wellhead setpoint pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for controlling a downhole pressure during drilling comprising:
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periodically sensing in real-time at least one fluid property of an input fluid into a well and of a return fluid from the well; inputting the at least one fluid property into of a drilling control system; calculating in real-time, using the drilling control system, a wellhead setpoint pressure that results in a predetermined downhole pressure at a predetermined location in the well, the calculation based at least in part on the at least one fluid property and an elasticity model of the well incorporating the at least one fluid property; and controllably regulating the flow of the return fluid to maintain the calculated wellhead setpoint pressure. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A drilling system for managed pressure drilling, comprising:
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at least one sensor configured to continually sense at least one fluid property of an input fluid to a well and a return fluid from the well; a controllably adjustable flow control apparatus disposed in a return flow line to regulate a flow of the return fluid; and a controller operably connected to the controllably adjustable flow control apparatus to instruct the controllably adjustable flow apparatus to regulate the flow of the return fluid to maintain a wellhead setpoint pressured based at least in part on an elasticity model of the well incorporating the at least one fluid property. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification