PRESSURE AND FLOW CONTROL IN DRILLING OPERATIONS

摘要

A WELL DRILLING SYSTEM FOR USE WITH A DRILLING FLUID PUMP (68) INCLUDES A FLOW CONTROL DEVICE (74) REGULATING FLOW FROM THE PUMP TO A DRILL STRING (16) INTERIOR; AND ANOTHER FLOW CONTROL DEVICE (76) REGULATING FLOW THROUGH A LINE IN COMMUNICATION WITH AN ANNULUS (20). FLOW IS SIMULTANEOUSLY PERMITTED THROUGH THE FLOW CONTROL DEVICES. A METHOD OF MAINTAINING A DESIRED BOTTOM HOLE PRESSURE INCLUDES DIVIDING DRILLING FLUID FLOW BETWEEN A LINE IN COMMUNICATION WITH A DRILL STRING INTERIOR AND A LINE IN COMMUNICATION WITH AN ANNULUS; THE FLOW DIVIDING STEP INCLUDING PERMITTING FLOW THROUGH A FLOW CONTROL DEVICE INTERCONNECTED BETWEEN A PUMP AND THE DRILL STRING INTERIOR; AND THE FLOW DIVIDING STEP INCLUDING PERMITTING FLOW THROUGH ANOTHER FLOW CONTROL DEVICE INTERCONNECTED BETWEEN THE PUMP AND THE ANNULUS, WHILE FLOW IS PERMITTED THROUGH THE FIRST FLOW CONTROL DEVICE.