Patent Application
20080011360
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, the use of “top,” “bottom,” “above,” “below,” and variations of these terms is made for convenience, but does not require any particular orientation of the components.
Turning now to the present figures, an exemplary drilling system 10 is illustrated in
As will be appreciated, the surface equipment 14 may include a variety of devices and systems, such as pumps, power supplies, cable and hose reels, control units, a diverter, a gimbal, a spider, and the like. Similarly, the riser equipment 16 may also include a variety of components, such as riser joints, fill valves, control units, and a pressure-temperature transducer, to name but a few. The riser equipment 16 facilitates transmission of the extracted resource to the surface equipment 14 from the stack equipment 18 and the well 12.
The stack equipment 18 also includes a number of components, such as blowout preventers and/or production or “Christmas” trees, for extracting the desired resource from the wellhead 20 and transmitting it to the surface equipment 14 and the riser equipment 16. In the presently illustrated embodiment, operation of the stack equipment 18 is controlled by an exemplary control system 22. The exemplary control system 22 includes a pressure regulator 24 and a plurality of valves 26 that control flow through the system 10. In some embodiments, one or more of the plurality of valves compose a portion of a blowout preventer or Christmas tree.
Further, in an exemplary embodiment, the pressure regulator 24 is a hydraulic pressure regulator and the plurality of valves 26 includes solenoid valves. As will be appreciated, valves 26 may be configured with a specific pressure rating, such as 3,000 psi. Often, in hydraulic systems, an initial supply pressure is provided to the control system 22, such as from a bank of accumulator tanks, that is higher than the pressure rating of various system components, such as valves 26, to facilitate maintenance of adequate pressure to the system components even during periods of high usage. In the exemplary system 10, the pressure regulator 24 enables management of the supply pressure to deliver a regulated pressure to downstream components, such as valves 26. While the pressure regulator 24 of the presently illustrated embodiment is a component of the stack equipment 18, it will be appreciated that, in other embodiments, the pressure regulator 24 may be disposed in other portions of the system 10, such as a component of the surface equipment 14, in full accordance with the present techniques. Additionally, certain embodiments may include multiple pressure regulators 24, which may be configured to receive and transmit control fluid at the same respective pressure levels as each other or, alternatively, such that two pressure regulators 24 each receive and/or transmit fluids at pressure levels that are different between the two regulators 24.
An exemplary pressure regulator 24 is illustrated in
The pressure regulator 24 also includes a pair of supply assemblies 44 disposed on opposite sides of the lower housing 34, and a pair of vent assemblies 46, which are also disposed on opposite sides of the lower housing 34 from one another. The supply and vent assemblies 44 and 46 may be secured to the lower housing 34 in any suitable fashion, such as by fasteners 42. While the exemplary pressure regulator 24 includes a pair of both supply pressure assemblies 44 and vent pressure assemblies 46, it should be noted that a different number of such assemblies may instead be employed in full accordance with the present techniques.
During operation, a control medium at a first pressure, such as 5,000 psi, may enter the pressure regulator 24 through the supply ports 48 of the supply assemblies 44, and the control medium may be output at a second, regulated pressure, such as 3,000 psi, via an regulated pressure outlet port 50 disposed in a side of the lower housing 34. Additionally, if the pressure inside the regulator 24 exceeds a certain threshold, the control medium may be vented from the regulator 24 through the vent ports 52 of the vent assemblies 46. In the presently illustrated embodiment, the pressure regulator 24 is a hydraulic pressure regulator and the control medium includes hydraulic fluid. In other embodiments, however, the control medium may be some other material, such as a pressurized gas. Consequently, while the instant description of the illustrated embodiments may refer to a control fluid, it will be appreciated that such description may apply to a control liquid in a hydraulic pressure regulator in accordance with one embodiment of the present invention, and does not necessarily preclude the use of a gaseous control medium in an alternative embodiment.
The internal operation of the exemplary regulator 24 may be better understood with reference to
As discussed in greater detail below, pressure within the supply and vent chambers 60 and 62 may apply a thrust force to the supply piston 64 and/or the vent piston 68 that acts against the biasing force provided by springs 66 and 70, respectively, such that supply ports 48 and vent ports 52 may be opened and closed. The biasing force supplied by springs 66 and 70 can be modified via a spring load adjustment mechanism 72 disposed at one end of the upper housing 32 and discussed in greater detail below. As may be appreciated, the exemplary regulator 24 includes various seals or O-rings 74, disposed between the components to maintain pressure within the regulator 24 and reduce or prevent leakage of materials, such as a control fluid, from or into the interior of regulator 24.
An axial sectional view of the exemplary regulator 24 is provided in
The opening and closing of the supply ports 48 and vent ports 52 may be better understood with reference to the detailed sectional views of
A control fluid entering the supply chamber 60 may pass to the vent chamber 62 through a separating shoulder 104 via a plurality of pressure transfer ports 106. In the present embodiment, vent shear seal rings 108 are disposed within a recess 110 of the vent piston 68. The vent shear seal rings 108 are similarly biased by a spring 112 against a pair of vent seal plates 114. The vent seal plates 114 also include first and second fluid passageways 116 and 118, respectively, which enable fluid to be vented from the vent chamber 62 through the vent ports 52. In the presently illustrated embodiment, the vent seal rings 108 are of a different size than the supply seal rings 84. Further, the exemplary second passageways 94 and 118 of the seal plates 90 and 114, respectively, are also of different sizes than one another and are based on the particular sizes and geometries of the seal rings 84 and 108, as discussed in greater detail below.
An initial operating state is depicted in
As the pressure downstream and within the regulator 24 increases and approaches the first pressure threshold, the hydraulic force on supply piston 64 becomes sufficient to move the supply piston 64 in the direction indicated by arrow 96 and toward the closed position generally illustrated in
As may be appreciated, as the pressure within the pressure regulator 24 continues to increase beyond the first pressure threshold, the thrust applied to the vent piston 68 by the internal pressure also increases, causing the vent piston 68 to move in the direction indicated by arrow 96. As the internal pressure reaches a second pressure threshold, the vent piston 68 and vent seal rings 108 are moved into an open position, as generally illustrated in
It will be noted that, in the presently illustrated embodiment, the supply piston 64 and the vent piston 68 may operate independent of one another. That is, movement of the supply piston 64 and supply seal rings 84 to control flow through the supply ports 48 is independent of the movement of vent piston 68 and vent seal rings 108 that generally control flow through the vent ports 52. The independent operation of the supply and vent piston 64 and 68 enable the use of two separate load springs 66 and 70 that may be specifically configured for a desired range of regulated and vent pressures, respectively. Further, the mechanical independence of supply piston 64 and vent piston 68 reduces the frictional forces that act against the thrust force applied to each piston by the internal pressure of the pressure regulator 24, and thereby enhances the sensitivity of the pressure regulator 24.
In other words, while a single piston carrying both seal rings 84 and seal rings 108 would experience frictional forces attributable to both sets of the seal rings 84 and 108, the supply and vent pistons 64 and 68 in the presently illustrated embodiment are subjected to only the frictional force attributed to their own respective seal rings 84 and 108 (in addition to any friction created by other components, such as seals 74). Consequently, the supply piston 64 and the vent piston 68 are each more responsive to a sudden increase or decrease in the pressure within the supply chamber 60 and the vent chamber 62. For example, in the general state of equilibrium illustrated in
In certain embodiments, the supply seal plates 90 may be specifically configured based on the geometries of their respective seal rings 84. For instance, in the embodiment illustrated in
Similarly, a vent seal plates 114 (
Certain embodiments of the present invention may also include a damping feature, such as that illustrated in
For instance, as pressure within the supply chamber increases, the supply piston 64 moves in the direction indicated by arrow 96 and reduces the available space within the damping chamber 140 for the control medium or fluid. Thus, the interaction between movement of the supply piston 64 and the damping chamber 140 forces control fluid within the chamber 140 to either pass through the mating feature 142 via one or more bleed ports 144 or around the outer circumference of the mating feature 142. Further, in one embodiment, a guide ring 146 may be disposed about the outer perimeter of the mating feature 142 to further inhibit flow of the control fluid around the outer perimeter. In one embodiment, the interaction of the damping chamber 140 and the mating feature 142 substantially reduces or prevents the undesirable effects of fluid-structure interaction within the pressure regulator 24.
Additionally, one or more embodiments of the present invention may also include an exemplary spring load adjustment mechanism 72, as generally illustrated in
Further, in one embodiment, an exemplary pressure regulator 24 includes an apparatus for flushing the interior of the upper housing 32. Notably, the exemplary pressure regulator 24 includes a fluid conduit 172 that connects a vent port 52 with an inlet port 174 formed in the end cap 40. The fluid conduit 172 may be generally defined by couplings 176 and 178 secured to the vent port 52 and inlet port 174, respectively, and a hose or pipe 180 that extends between the coupling 176 and 178. As the vent ports 52 are opened, the control fluid being vented from the vent chamber 62 may be routed through the fluid conduit 172 and into a chamber 182 in which the load spring 66 and 70 are disposed. As may be appreciated, the fluid injected into the spring chamber 182 may pass through or around the plunger 156, such as through flow ports formed in the plunger 156 or the grooves 162. This pressurized fluid is then routed through the chamber 182 and exits the chamber through the bleed ports 184 disposed at one end of the upper housing 32. In one embodiment related to subsea operation of the exemplary pressure regulator 24, the routing of control fluid through the fluid conduit 172 and the spring chamber 182 may flush sea water from the spring chamber 182, thereby reducing or preventing growth of marine life within the spring chamber 182. In one embodiment, check valves may also be added to the bleed ports 184 to prevent sea water from entering the spring chamber 182.
While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.
