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Pressure and flow control in drilling operations

  • US 9,080,407 B2
  • Filed: 04/10/2012
  • Issued: 07/14/2015
  • Est. Priority Date: 05/09/2011
  • Status: Active Grant
First Claim
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1. A method of maintaining a desired bottom hole pressure during a well drilling operation, the method comprising:

  • dividing flow of drilling fluid between a line in communication with an interior of a drill string and a line in communication with an annulus formed between the drill string and a wellbore, the dividing including permitting flow through a first flow control device interconnected between a pump and a fourth flow control device, which is included in a rig standpipe manifold, the fourth flow control device being interconnected between the first flow control device and the drill string, the dividing also including permitting flow through a second flow control device interconnected between the pump and the annulus, while flow is permitted through the first flow control device;

    closing the first flow control device after pressures in the line in communication with the interior of the drill string and the line in communication with the annulus equalize;

    making a connection in the drill string after the first flow control device closing;

    then permitting flow through the first flow control device while permitting flow through the second flow control device;

    then closing the second flow control device after pressures again equalize in the line in communication with the interior of the drill string and in the line in communication with the annulus; and

    permitting flow through a third flow control device continuously during the dividing, the first flow control device closing, the making and the second flow control device closing, thereby maintaining a desired annulus pressure corresponding to the desired bottom hole pressure, wherein the dividing, the first flow control device closing, the permitting flow through the first flow control device, the second flow control device closing, and the permitting flow through the third flow control device are performed by an automated control system, the control system including a predictive device and a data validator, wherein the predictive device outputs at least one predicted parameter value to the data validator, and wherein the data validator outputs at least one validated parameter value to a hydraulics model which determines the desired annulus pressure.

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