CHOKE VALVE SEPARATOR

Abstract

Choke valve separator, distinctive in that it comprises: an inlet, an inlet flow control valve, a choke and fluid conditioner part coupled to receive fluid from the inlet, comprising elements with conduits for flow per se or with the elements as stacked, at least in a final section thereof in the direction of flow the conduits have spiral or helical shape providing spiral or helical outlet flow from said part, a separation part, coupled to receive the fluid from the choke and fluid conditioner part comprising a volume into which the received fluid due to spiral flow or helical flow or gravity separates and distributes into phase volumes, at least two outlets from the separation part, and a housing.

Claims

1. A choke valve separator comprising: an inlet; an inlet flow control valve; a choke and fluid conditioner part coupled to receive fluid from the inlet, comprising elements with conduits for flow per se or with the elements as stacked, at least in a final section thereof in the direction of flow the conduits have spiral or helical shape providing spiral or helical outlet flow from the part; a separation part, coupled to receive the fluid from the choke and fluid conditioner part, comprising a volume into which the received fluid due to spiral flow or helical flow or gravity separates and distributes into phase volumes; at least two outlets from the separation part; and a housing.

2. The choke valve separator according to claim 1, wherein the choke and fluid conditioner part comprises several spiral-shaped conduits, each conduit having length of at least 0.05 m, more preferably at least 0.1 m, even more preferably at least 0.2 m, even more preferable at least 0.5 m, most preferable at least 1 m.

3. The choke valve separator according to claim 2, wherein the conduits have a cross section shape that is circular, quadratic, rectangular or hexagonal, arranged with closest packing wall to wall or with common sidewalls.

4. The choke valve separator according to claim 1, wherein the choke and fluid conditioner part comprises several spiral-like conduits, the conduits extend radially outwards from the inlet, orthogonal or inclined as conical spirals, preferably each spiral comprises at least one revolution, more preferably at least three revolutions.

5. The choke valve separator according to claim 1, comprising several outlets, at different radial distances from the inlet and at different elevations, the number of outlets equals or is larger than the number of phases, preferably at least one outlet for each phase volume.

6. The choke valve separator according to claim 1, wherein the outlet and inlet into spiral shaped conduits of the choke and fluid conditioner part has enhanced cross section area for flow, compared to the remaining parts of the conduits.

7. The choke valve separator according to claim 1, wherein the control valve can control the cross section area for flow from 0 to 100%, stepwise or continuous.

8. The choke valve separator according to claim 1, comprising phase transmitters in the separation part, at different distances from an axis of fluid rotation and at different elevations, and in inlet and fluid outlets, pressure transducers in the inlet and outlets, and remotely controllable valves in the outlets, coupled in real time to a controller.

9. The choke valve separator according to claim 1, comprising at least one of the following features, in any combination: a stack of discs or cone-like plates with integrated spiral shaped conduits, a stack of discs or cone-like plates having spiral shaped grooves on at least one side, wherein the spiral shaped conduits have been formed by stacking the discs or plates, and a stack of discs or cone-like plates having a spiral shaped opening punched out or otherwise formed and discs or plates without a spiral shaped opening, wherein the spiral shaped conduits have been formed by alternatingly stacking discs or plates with and without spiral shaped opening.

10. (canceled)

Description

FIGURE

[0056] FIG. 1 illustrates a preferable embodiment of a choke valve separator of the invention.

[0057] FIG. 2 illustrates the choke valve separator of the invention of FIG. 1, in a mode before startup of normal operation,

[0058] FIG. 3 illustrates the choke valve separator of the invention in a mode of semi cyclonic operation,

[0059] FIGS. 4 and 5 illustrate a part of the technical effect of the invention,

[0060] FIGS. 6a, 6b, 6c and 6d illustrate details of preferable embodiments, wherein protrusions of stackable elements fit into small recessions or grooves of the adjacent face of matching stackable elements,

[0061] FIGS. 7a, 7b, 7c and 7d illustrate some possible field applications, and

[0062] FIG. 8 illustrates an embodiment of the choke valve separator of the invention.

DETAILED DESCRIPTION

[0063] FIG. 1 illustrates a choke valve separator 1 of the invention. The choke valve separator 1 comprises: an inlet 2; a choke and fluid conditioner part 3 arranged coaxially outside the inlet and fluidly coupled to the inlet; a separation part 4 arranged coaxially outside the choke and fluid conditioner part and coupled to receive the fluid from the choke and fluid conditioner part as a conical spiral flow, having the main velocity component as a tangential velocity component. The separation part comprises: an annular phase volume 4l for a lighter phase and at least one further annular phase volumes 4h, 4h1, 4h2 . . . , for one or more heavier phases, with annular volumes for heavier phases coaxially outside annular volumes for lighter phases. The separation part contains an open volume into which the phases can separate and distribute into annular phase volumes during normal operation, the size of each volume depending on the phase composition. Further, the choke valve separator 1 comprises: an outlet 5l, 5h, 5h1, . . . , from each respective annular phase volume: an inlet flow control valve 6, a control valve actuator 6a, a housing 7 and a sand outlet 8. A volume with possible swirl generation 9 is also indicated.

[0064] In preferable embodiments, in order to eliminate or reduce possible problems caused by swirl generation, the conduits of the choke and fluid conditioning part converge at the outlets or a short distance upstream the separation part. The choke valve separator of the invention comprises one or more of the following features for this purpose, in any combination: conduit walls ending at downstream ends toward the conduit outlet as knife like edges, outlets from the conduits inside a common outlet pipe, conduits are combined into fewer and fewer conduits toward the outlet, ending as one larger cross section area conduit delivering the choked and fluid conditioned flow to the separation part. Most preferably, the conduits converge inside a shroud before the fluid flows into the separation part, neighbor conduit walls comprises sharp knife like ends where conduits converge, thereby eliminating or limiting stagnant volumes and flows of different velocities causing swirling.

[0065] The lighter phase is typically a gas phase or a lighter liquid phase. The heavier phase or phases are typically liquids, such as oil and water. The annular phase volumes are annular-shaped volumes where respective phases accumulate during cyclone-type separation. At start up or insufficient inlet pressure, gravitational separation can take place in the separation part, as the only or a significant separation mechanism.

[0066] In the illustrated embodiment, the angle for fluid flow from the inlet to the choke and fluid conditioner part is acute, but can be orthogonal or low. With an acute angle, the fluid velocity is preferably reduced by having increased cross section for flow into the conduits from the inlet.

[0067] FIG. 2 illustrates the choke valve separator of the invention of FIG. 1, in a mode before startup of normal operation. As natural due to gravity, the phases have separated and been distributed into layers at different elevations, for a vertically standing choke valve separator. More specifically, gas, 41 has accumulated in the top of the choke valve separator; oil 4h1 in an intermediate part, and water 4h2 in a lower part of the illustrated vertically standing choke valve separator. During normal operation, the phase separate and distribute into annular volumes, the lighter phases inside heavier phases, as seen in FIG. 1. As mentioned, alternative embodiments of the choke valve separator comprises additional outlets (not illustrated) to ensure clean phases in the outlets at all time, also in the mixed separation type modes between start up and stable normal operation. For example, with the phases gas, oil and water, three outlets in the top and three outlets in the bottom, and three outlets in the sidewall at different elevation, can be convenient, referring to a vertical standing choke valve separator, meaning that the axis of rotation for cyclonic type separation is vertical. Outlets in the housing wall, and in top and bottom parts of the housing wall, the outlets not extending into the volume of the separation part, may improve the separation effect by not disturbing the cyclonic type flow and separation. Feasible instrumentation is commercially available from Roxar, Schlumberger and other suppliers. Feasible valves are commercially available from valve suppliers, for example Mokveld Valves. Preferably, the sensors and valves are operating in real time, automatically as controlled by algorithms or remotely controllable.

[0068] FIG. 3 illustrates the choke valve separator of the invention in a mode of semi cyclonic operation, which is a mixed type separation where both cyclonic separation and gravitational separation contribute. Due to the forces involved, the phases gas 4l, oil 4h1 and water 4h2 typically distribute into cup like or curved disc like or bowl like volumes, examples of which can be seen in FIG. 3. This can be seen easiest with the longitudinal section of the oil phase volume 4h1, having shape like a thick walled cup or disc. However, the top of the gas volume 4l is terminated by the top of the separation part volume and the bottom of the water phase volume 4h2 is terminated by the bottom of the separation part volume.

[0069] FIGS. 4 and 5 illustrate a part of the technical effect of the invention. FIG. 4 illustrates a traditional choke valve 10 as coupled to a separator 11. With the choke valve separator 1 of the invention, as illustrated in FIG. 5, the choke valve separator 1 receives the well stream from the wellbore 12 and deliver the phases through separate outlets, replacing the traditional choke valve and separator. Furthermore, the phases delivered from the choke valve separator have never undergone intense mixing as in a typical choke valve, resulting in phases more feasible for further separation.

[0070] FIGS. 6a, 6b, 6c and 6d illustrate details of preferable embodiments, wherein protrusions of stackable elements fit into small recessions or grooves of the adjacent face of matching stackable elements. Such notch and groove-like features are feasible for all embodiments for which the choke and fluid conditioner part comprises stacked elements. Direct metal to metal sealing and elimination of or reduction of the number of any sealing elements between stackable elements can be achieved thereby.

[0071] FIGS. 7a, 7b, 7c and 7d illustrate some possible field applications. More specifically, satellite field can be tied in to installations of another operator, as illustrated in FIG. 7a, since improved separation as provided by the invention allows measurement of petroleum fluid at improved accuracy. So-called subsea on a stick is feasible, with a choke valve separator on a typically unmanned platform, cf. FIG. 7b, in addition to possible choke valve separators arranged subsea. The choke valve separator of the invention may eliminate or replace other equipment, as seen by comparing the left side of FIGS. 7c and 7d with the right side of said figures, respectively.

[0072] FIG. 8 illustrates an embodiment of the choke valve separator of the invention, comprising a pipe spool as housing. The effect is to simplify production and certification of the choke valve separator.

[0073] The choke valve separator of the invention is conveniently made using feasible structural steel as main construction material. However, other metals or alloys, ceramic material, composite materials and polymers, and combinations thereof, can be used, as found convenient using good engineering practice.

[0074] The choke valve separator of the invention can have many embodiments, particularly in how the inlet, the choke and fluid conditioner part and the control valve are designed. The choke and fluid conditioner part may for example comprise parallel flow conduits toward the inlet, coaxial to the inlet, with straight parallel conduits, with twisted or rotated conduits in an intermediate section, but having stacks of spiral shaped or conical spiral shaped conduits inside a separation part toward the outlet from the choke and fluid conditioner part. For embodiments with very long conduit lengths, for example, parallel conduits of 5, 10, 30 or 50 m, and for choke valve separators able to withstand open well pressure, such embodiments can be preferable to reduce pressure housing dimensions. The inlet valve can be a linear actuated valve blocking single conduits or groups of conduits stepwise or discrete. Another embodiment is to combine the spiral shaped part of the choke and fluid conditioner part with a cyclone, having the exit from the choke and fluid conditioner part in a position close to the axis of rotation, in contrast to a typical cyclone inlet, which has inlet tangential just inside the outer periphery in the upper end of the cyclone. A further embodiment comprises an exit from the choke and fluid conditioner part in a position tangential just inside the outer periphery in the upper part of a cyclone, which is one reason why in claim 1 it is not specified as obligatory that the choke and fluid conditioner part shall be arranged coaxially inside the separation part, contrary to what is preferable for most embodiments. The choke valve separator of the invention may comprise a conical bottom part or top or both conical bottom and top for embodiments with separation part designed like a cyclone.