Subsea Pressure Reduction System

Patent metadata

Field	Value
Publication number	US-2016010418-A1
Application number	US-201514861598-A
Country	US
Kind code	A1
Filing date	Sep 22, 2015
Priority date	Oct 19, 2011
Publication date	Jan 14, 2016
Grant date	—

Abstract

A system for reducing pressure in a subsea operator. In one embodiment, a subsea system includes an operator and a deintensifier. The operator includes a housing and a piston. The piston is movably disposed within the operator housing and divides an inner volume of the operator housing into a closing chamber and a second chamber. The deintensifier is fluidically coupled to the operator. The deintensifier includes a housing and a piston. The piston includes a closing surface and an opening surface. The closing surface is fluidically coupled to the second chamber of the operator housing. The opening surface is fluidically coupled to ambient pressure. The area of the closing surface is greater than an area of the opening surface so as to increase the pressure differential between the closing chamber and the second chamber and assist in moving the operator piston to the closed position.

First claim

What is claimed is:

1 . A subsea system, comprising:
an operator, comprising:
an operator housing;
an operator piston movably disposed within the operator housing between and open position and a closed position, the operator piston being sealingly engaged with an inner surface of the operator housing and an inner volume of the operator housing being divided into a closing chamber and a second chamber by the operator piston; and
a piston rod coupled to the operator piston and extended from the operator housing; and
a deintensifier fluidically coupled to the operator, the deintensifier comprising:
a deintensifier housing comprising an interior;
a deintensifier piston movably disposed within the interior of the deintensifier housing, the deintensifier piston comprising a closing surface fluidically coupled to the second chamber of the operator housing and an opening surface fluidically coupled to ambient pressure; and
wherein an area of the closing surface is greater than an area of the opening surface so as to increase the pressure differential between the closing chamber and the second chamber and assist in moving the operator piston to the closed position.

2 . The subsea system of claim 1 , wherein the deintensifier housing further comprises:
a piston chamber fluidically coupled to the second chamber, the closing surface of the deintensifier piston being disposed in the piston chamber; a mandrel chamber separated from the piston chamber by an internal wall of the deintensifier housing, the opening surface of the piston being disposed in the mandrel chamber; and a port providing a passage from an interior of the mandrel chamber to an exterior of the deintensifier housing.

3 . The subsea system of claim 2 , wherein:
the piston further comprises a mandrel extending through the internal wall into the mandrel chamber; and an end of the mandrel comprises the opening surface of the deintensifier piston.

4 . The subsea system of claim 2 , wherein:
an inner volume of the piston chamber is divided into a deintensifier closing chamber and a deintensifier slack chamber by the deintensifier piston; the deintensifier slack chamber comprises a port that fluidically couples the deintensifier slack chamber to a pressure source; and the deintensifier closing chamber comprises at least as great a fluid capacity as the second chamber of the hydraulic operator.

5 . The subsea system of claim 1 , wherein the second chamber of the hydraulic operator is one of an opening chamber and a slack chamber.

6 . The subsea system of claim 1 , wherein the deintensifier further comprises:
a barrel disposed within the deintensifier housing, an annulus being formed between an outer surface of the barrel and an inner surface of the deintensifier housing; and wherein the deintensifier piston is an annular piston disposed in the annulus, and sealingly engaged with the outer surface of the barrel.

7 . The subsea system of claim 6 , further comprising:
a closing chamber formed at least partially by the closing surface of the deintensifier piston and the inner surface of the deintensifier housing; an opening chamber formed at least partially by the opening surface of the deintensifier piston, the outer surface of the barrel, and the inner surface of the deintensifier housing; and the closing chamber comprises at least as great a fluid capacity as the second chamber of the hydraulic operator.

8 . The subsea system of claim 1 , further comprising a second deintensifier, wherein a ratio of closing surface to opening surface of the second deintensifier piston is greater than a ratio of closing surface to opening surface of the deintensifier piston so as to be able to effectively lock the operator piston in the closed position.

9 . The subsea system of claim 8 , further comprising a switch configured to couple the second chamber with either one of both the deintensifier or the second deintensifier.

10 . The subsea system of claim 1 , further comprising:
a switch configured to selectively couple and uncouple the deintensifier with the second chamber of the hydraulic operator; and a detector configured to detect an operating parameter and control the switch on application of a control signal.

11 . The subsea system of claim 1 , further comprising more than one deintensifier.

12 . The subsea system of claim 11 , wherein the deintensifiers are fluidically coupled in series, in parallel, or any combination of series and parallel.

13 . The subsea system of claim 1 , further comprising a control system configured to selectively fluidically uncoupling the deintensifier piston opening surface from ambient pressure.

14 . The subsea system of claim 13 , wherein the control system further comprises a selector valve movable between a normal closing mode position where the deintensifier piston opening surface is fluidically uncoupled from ambient pressure and a self closing mode position where deintensifier piston opening surface is fluidically coupled to ambient pressure.

15 . The subsea system of claim 14 , further comprising:
an accumulator selectively fluidically coupled with the closing chamber of the operator housing; wherein the control system is configured to operate in a dead man/auto-shear self closing mode wherein the control circuit allows closure of the operator piston by fluidically coupling the deintensifier to ambient pressure and then fluidically coupling the accumulator with the closing chamber.

16 . The subsea system of claim 13 , further comprising a bypass valve configured to allow fluid pressure to bypass the deintensifier through a bypass conduit.

17 . The subsea system of claim 13 , further comprising:
a separator fluidically coupled with the closing chamber of the operator housing, the separator comprising an internal movable element; and a sensor capable of measuring the position of the internal moveable element and transmitting a signal representing the position.

18 . The subsea system of claim 1 , further comprising a blowout preventer, wherein the piston rod is coupled to a ram of the blowout preventer.

19 . The subsea system of claim 1 , wherein ambient pressure is hydrostatic pressure.

20 . A subsea system, comprising:
an operator, comprising:
an operator housing;
an operator piston movably disposed within the operator housing between and open position and a closed position, an inner volume of the operator housing being divided into a closing chamber, a slack chamber, and an opening chamber by the operator piston; and
a piston rod coupled to the operator piston and extended from the operator housing;
a tandem booster attached to the operator, comprising:
a booster housing;
a booster piston movably disposed within the booster housing between and open position and a closed position, an inner volume of the booster housing being divided into a closing chamber and an opening chamber by the booster piston; and
the booster piston being extended from the booster housing and coupled to the operator piston; and
a deintensifier fluidically coupled to the operator, the deintensifier comprising:
a deintensifier housing;
a deintensifier piston movably disposed within an interior surface of the deintensifier housing, the deintensifier piston comprising a closing surface fluidically coupled to the booster opening chamber and an opening surface fluidically coupled to ambient pressure; and
wherein an area of the closing surface is greater than an area of the opening

Assignees

• Cameron Int Corp
• Shell Oil Co

Inventors

• Van Wijk Johannes
• Mcwhorter David J
• Whitby Melvyn F
• Gaude Edward C

Classifications

• E21B33/0355 Primary

  Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads · CPC title

• E21B33/061

  Ram-type blow-out preventers, e.g. with pivoting rams · CPC title

• E21B33/064

  specially adapted for underwater well heads · CPC title

• F15B11/032

  by means of fluid-pressure converters · CPC title

• F15B3/00

  Intensifiers or fluid-pressure converters, e.g. pressure exchangers; Conveying pressure from one fluid system to another, without contact between the fluids {(fluid-driven pumps F04B9/08)} · CPC title