METHOD AND APPARATUS FOR CONTROLLING THE FLOW OF WELLBORE RETURNS

摘要

A method and apparatus to regulate the down-hole hydrostatic pressure in a wellbore are provided which depend on regulating the resistance to the flow of wellbore returns produced by the wellbore. The resistance may be provided by the internal gas pressure in a gas/liquid separator receiving the flow of wellbore returns, where the internal gas pressure is regulated by an adjustable back pressure valve and a gas source. Alternatively or in addition, the resistance may be provided by a pump receiving the flow of wellbore returns, where the resistance of the pump is regulated by adjusting the speed of the pump.

主权项

1. A method of controlling a flow of wellbore returns to regulate the down-hole hydrostatic pressure of a wellbore, the method comprising the steps of:
(a) directing the flow of wellbore returns through an intake flow line into a gas/liquid separator having a gas outlet; (b) separating gas associated with the wellbore returns to produce a disassociated gas in the separator; and (c) selectively restricting the flow of the disassociated gas out of the separator through the gas outlet to regulate the internal gas pressure of the separator, wherein the internal gas pressure of the separator is opposed to the flow of the wellbore returns through the intake flow line from the wellbore into the separator.