Method and apparatus for controlling the flow of wellbore returns

Patent metadata

Field	Value
Publication number	US-2016168932-A9
Application number	US-201313872713-A
Country	US
Kind code	A9
Filing date	Apr 29, 2013
Priority date	Apr 27, 2012
Publication date	Jun 16, 2016
Grant date	—

Abstract

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.

First claim

What is claimed is:

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.

2 . The method of claim 1 further comprising the step of introducing gas into the separator from a gas source to increase the internal gas pressure of the separator.

3 . 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 from the wellbore to a pump, and through the pump; and (b) selectively varying the speed of the pump to vary the resistance of the pump to the flow of wellbore returns through the intake flow line from the wellbore to the pump.

4 . The method of claim 3 wherein the pump is a multiphase pump, a positive displacement pump, a twin screw pump, a centrifugal pump, or a diaphragm pump.

5 . The method of claim 3 further comprising the step of measuring the volume of wellbore returns passing through the pump.

6 . An apparatus for controlling a flow of wellbore returns to regulate the down-hole hydrostatic pressure of a wellbore, the apparatus comprising:
(a) an intake flow line for receiving the flow of wellbore returns from the wellbore; (b) a gas/liquid separator having an inlet for interconnection to the intake flow line for receiving the flow of wellbore returns, and a gas outlet; and (c) a back pressure valve interconnected to the gas outlet, the back pressure valve being adjustable to selectively restrict the flow of gas out of the separator and thereby regulate the internal gas pressure of the separator.

7 . The apparatus of claim 6 further comprising a gas source interconnected to the separator.

8 . An apparatus for controlling a flow of well bore returns to regulate the down-hole hydrostatic pressure of a wellbore, the apparatus comprising;
(a) an intake flow line for receiving the flow of wellbore returns from the wellbore; (b) a pump having a pump inlet interconnected to the intake line for receiving the flow of wellbore returns, and a pump outlet for discharging the flow of wellbore returns, wherein the speed of the pump is adjustable to selectively vary the resistance of the pump to the flow of wellbore returns through the intake flow line from the wellbore to the pump.

9 . The apparatus of claim 8 wherein the pump is a multiphase pump, a positive displacement pump, a twin screw pump, a centrifugal pump, or a diaphragm pump.

10 . The apparatus of claim 8 further comprising:
(a) a gas/liquid separator having a separator inlet and a gas outlet, the separator inlet being interconnected to the intake flow line for receiving the flow of wellbore returns; and
(b) a back pressure valve interconnected to the gas outlet, the back pressure valve being adjustable to selectively restrict the flow of gas out of the separator and thereby regulate the internal gas pressure of the separator.

11 . The apparatus of claim 10 further comprising an intake valve interconnected to the intake flow line for selectively restricting the flow of wellbore fluids through the intake flow line from the wellbore to either the pump, or the separator, or both.

12 . The apparatus of claim 10 further comprising a gas source interconnected to the separator.

Assignees

• Weatherford Technology Holdings Llc

Inventors

• Boyd Michael

Classifications

• E21B21/106

  Valve arrangements outside the borehole, e.g. kelly valves (valves specifically for maintaining circulation of drilling fluid while connecting or disconnecting tubular joints E21B21/019) · CPC title

• E21B21/063

  by separating components · CPC title

• E21B2021/007

  Fixed Constructions · mapped topic

• E21B21/00 Primary

  Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor (freeing objects stuck in boreholes by flushing E21B31/03) · CPC title

• E21B21/08 Primary

  Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure (valve arrangements therefor E21B21/10) · CPC title