BACKGROUND

[0001] The present disclosure relates to surface well choke systems and methods for controlling the flow of fluid to and from a well.

[0002] Surface well choke systems used on production wells typically restrict fluid flow from an inlet to an outlet by a manually adjustable hand wheel or power actuator that moves a tapered stem into and out of a choke seat. These types of choke mechanisms are imprecise and slow to respond to change the fluid restriction. Additionally, the interface between the tapered stem and seat is subject to debris contamination and erosion over time.

DESCRIPTION OF DRAWINGS

[0003] FIG. 1 is a schematic partial cross-sectional view of an example well system with a surface well choke system.

[0004] FIGS. 2A and 2B are a schematic cross-sectional front view (FIG. 2A) and a side view (FIG. 2B) of an example well choke that can be used in the surface well choke system of FIG. 1.

[0005] FIG. 3 is a schematic cross-sectional view of an example well choke system incorporating an example bypass.

[0006] FIG. 4 is a schematic cross-sectional view of an example well choke system incorporating parallel well chokes.

[0007] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0008] Referring first to FIG. 1, an example well system 10 includes a substantially cylindrical wellbore 12 that extends from a wellhead 14 at the surface 16 downward into the Earth into one or more subterranean zones of interest 18 (one shown). In certain instances, the formations of the subterranean zone are hydrocarbon bearing, such as oil and/or gas deposits, and the well system 10 will be used in producing the hydrocarbons and/or used in aiding production of the hydrocarbons from another well (e.g., as an injection or observation well). Notably, the example well system 10 is described herein for convenience of reference only, and the concepts herein are applicable to virtually any type of well. The wellhead 14 has a flange 22 for attaching equipment to the wellhead 14. A well choke system 24 is shown attached to the wellhead 14, for example, by a corresponding wellhead attachment flange 23 of the choke system 24 being bolted and/or otherwise affixed to the flange 22. The well choke system 24 is further shown coupled to pipeline 26, for example, a production or injection pipe. Fluids travel between the wellbore 12 and the pipeline, through the wellhead 14 and well choke system 24.

[0009] Referring to FIGS. 2 A and 2B, an example well choke 100 that can be used in a well choke system 24 is shown in a detail cross-sectional front view and a side view, respectively, to show the working aspects of the choke. The well choke 100 controls the flow of fluid from its inlet to its outlet, or in the context of the well system 10 of FIG. 1, the flow between the wellhead 14 and pipeline 26. In certain instances, the well choke 100 is full bore, where the smallest flow area through the choke 100, including an inlet and outlet of the choke 100, is the same (precisely or substantially) or larger than the flow area through the wellhead 14. In certain instances, the smallest diameters through the inlet and the outlet of the choke 100 are the same as or larger than the bore diameter of the wellhead 14. In other instances, the well choke 100 can have other, different flow areas or inner diameters.

[0010] The well choke 100 has a main body 101 that internally defines a fluid switch 102 and a variable flow resistance flow chamber 104. The inlet to the fluid switch 102 functions as an inlet of the well choke 100. The fluid switch 102, as discussed in more detail below, determines the path of the fluid flow through the well choke 100. The outlet from flow chamber 104 functions as an outlet of the well choke 100 and houses pathways of high and low flow rate reduction.

[0011] The flow chamber 104 has an indirect flow chamber inlet 106 and a direct flow chamber inlet 108, where the indirect flow chamber inlet 106 presents a flow path with more resistance to flow to an exit outlet 110 than the direct flow chamber inlet 108. The exit outlet 110 supplies fluid to the outlet of the well choke 100. The flow chamber 104 has a sidewall 105 apart from the exit outlet 110 and that defines the flow chamber inlets 106 and 108. FIGS. 2 A and 2B show a generally disk shaped chamber, where the sidewall 105 is curved to form a circular shape and the chamber has a low height to diameter aspect ratio. The exit outlet 110 is shown as circular opening in an end wall, near the center of the flow chamber 104, and in certain instances, with a center on the center axis of the flow chamber 104. In other instances, the shape of the chamber, shape of the sidewalls, exit location, exit orientation and/or exit shape could be different. For example, the chamber need not be disk shaped, but rather could be rectangular, spherical, and/or other shape.

[0012] The indirect flow chamber inlet 106 opens an indirect flow path 114 to the flow chamber 104 and directs incoming flow in a trajectory that is not directly toward the exit outlet 110. This indirect trajectory provides a higher reduction in flow rate towards the exit outlet 110 than a more direct trajectory would, because instead of flowing directly toward the outlet 110, the flow tends to circle the outlet 110 in sequentially smaller circles until it reaches the outlet 110. In instances having a curved sidewall 105, the curvature of the sidewall 105 facilitates this circling by redirecting impinging and nearby flow to circle around the outlet 110. In certain instances, the inlet 106 directs flow in a trajectory parallel to the tangent of the curved sidewall 105. The indirect flow chamber inlet 106 results in restriction in net fluid flow rate while substantially maintaining flow velocity from the indirect flow chamber inlet 106 to the exit outlet 110, because the restriction is produced by the longer flow path and not a reduction in flow area. This rapidly reduces fluid flow rate while maintaining a large pressure drop.

[0013] The direct flow chamber inlet 108 opens a direct flow path 116 to the flow chamber 104 and directs incoming flow more directly to the exit outlet 110 than the indirect flow inlet 106. In certain instances, the direct flow chamber inlet directs incoming flow directly to the outlet 110, for example, radially in an embodiment having a circular exit outlet 110. This more direct flow provides lower reduction in fluid flow rate towards the exit outlet 110 than the fluid flow from the indirect inlet 106, because the flow tends to flow in a substantially straight and direct path from the direct flow chamber inlet 108 to the exit outlet 110. In certain instances, the direct flow chamber inlet 108 additionally has an island along the centerline of the direct flow chamber inlet 108 that straightens fluid flow as it passes through the direct flow chamber inlet 108 toward the exit outlet 110.

[0014] The fluid switch 102 controls the path, and thus the resistance to flow rate, of the fluid flow through the well choke 100. The fluid switch 102 has a fluid switch inlet 112, the indirect flow path 114 directed towards the indirect flow chamber inlet 106, the direct flow path 116 directed towards the direct flow chamber inlet 108, and a movable flow deflector 118. [0015] The fluid switch 102 is upstream relative to the flow chamber 104. The fluid switch inlet 112 receives flow from the inlet to the choke 100. In certain instances, the fluid switch inlet 112 has the same flow area (e.g., same diameter) as the exit outlet 110 of the flow chamber 104. In other instances, the flow area of the exit outlet 110 and fluid switch inlet 112 can be different. In certain instances, the direct flow path 116 is linear (substantially or precisely) from the fluid switch inlet 112 to the direct flow chamber inlet 108, tracking along a sidewall of the fluid switch 102. The fluid switch 102 also has an angled offset pathway that defines the indirect flow path 114. As shown, the indirect flow path 114 tracks a curved sidewall leading to the indirect flow chamber inlet 106, but could be shaped differently.

[0016] The movable flow deflector 118 is located upstream of the indirect flow path 114 and direct flow path 116. The deflector 118 is moved in the flow by an actuator 119. The flow deflector 118 is shown residing opposite the indirect flow path 114. Thus, movement of the flow deflector 118 into the flow, toward the indirect flow path 114 deflects the fluid flow down the indirect flow path 114, or movement of the deflector 118 out of the flow, away from the indirect flow path 114, allows the fluid to flow down the direct flow path 116. The fluid deflector 118 need not fully close off the direct flow path 116 to direct flow down the indirect flow path 114, but rather creates a perturbation to the flow that tends to deflect the flow to the indirect flow path 114. Displacing the deflector 118 from flush with the wall of the inlet 112 to 20%-30% of the transverse dimension of the flow area (e.g., diameter) is enough to deflect the fluid flow to flow (substantially or wholly) along the indirect flow path 114. In other applications, depending on flow rate and shape of the deflection, displacing the deflection 118 from flush with the wall of the inlet to 10% of the transverse dimension of the flow area is enough to deflect the flow while in other applications, displacements in excess of 50% are needed. No displacement of the movable flow deflector 118 into the inlet flow path of the fluid switch 102 allows the fluid to flow along the direct flow path 116. Notably, the moveable flow deflector 118 need not be moved to its full extent into the flow. For example, the flow deflector 118 can be continuously adjustable between a retracted position (e.g., flush with the wall of the inlet 112 or other) and its full extent. Each intermediate position provides a different degree of perturbation to the flow, and thus, deflects different amounts of flow along the direct flow path 116 and the indirect flow path 114. Also, although only one flow deflector 118 is shown in FIGS. 2A and 2B, in other instances, more than one could be provided. In certain instances, multiple flow deflectors 118 are provided on the same side of the flow, on opposite sides of the flow or otherwise arranged.

[0017] The actuator 119 of the movable flow deflector 118 can take many forms. In certain instances, the actuator 119 is a solenoid, locking solenoid, piezoceramic, voice coil, motor, magnetostrictor, ferroelectric, relaxor ferroelectric, pump, bellow, blower, a combination thereof, and/or others.

[0018] Referring to FIG. 3, another configuration of well choke 100' that can be used in a well choke system 24 is shown in front cross-sectional view. The well choke 100' is like the choke 100 of FIGS. 2A and 2B, including a fluid switch 102, moveable flow deflector 118, indirect flow path 114, direct flow path 116, variable flow resistance flow chamber 104, and exit outlet 110. The well choke 100' additionally has a parallel bypass flow path 200 that allows a portion of the flow through the choke 100' to bypass (and thus not flow through) the fluid switch 102 and flow chamber 104. The bypass 200 lessens the effect of the flow chamber 104 in changing the total flow through the choke 100'.

[0019] Referring to FIG. 4, another configuration of well choke 100" that can be used in a well choke system 24 is shown in front cross-sectional view. The well choke 100" has two parallel paths, each with its own fluid switch 102, moveable flow deflector 118, indirect flow path 114, direct flow path 116, variable flow resistance flow chamber 104, and exit outlet 110. In other instances, additional parallel paths, with or without a switch, deflector and chamber, can be provided. The moveable flow deflectors 118 can be actuated independently, allowing none, one or both of the flow chambers 104 to provide resistance at a given time. Therefore, instead of providing binary changes in flow resistance, the two parallel paths can provide at least three different degrees of flow resistance. Additional parallel paths can enable providing additional degrees of flow resistance. Arrangements like FIG. 4 can also include a bypass path, like bypass path 200.

[0020] Referring back to FIG. 1, in certain instances, the well choke system 24 has a controller 120 communicably coupled to the actuator or actuators (e.g., actuator 119) of the choke (e.g., choke 100, 100' or 100") to control flow through the choke. The controller 120 can respond to a user input and/or an input from another controller, computer or other. The controller 120 can operate the actuator to a steady state position and/or operate the actuator at a specified duty cycle. Because the flow deflector need not move across the entire flow area and need not be configured to seal the entire flow area, it can be lightweight and moved quickly. In certain instances, the flow deflector can be moved at a duty cycle of between 0.001 Hertz and 1 Hertz, and in certain instances, up to 100 Hertz or higher. The controller 120 and the actuator of the flow deflector can be coupled by wire (electrical, optical and/or other) or wireless connection.

[0021] In certain instances, the well choke system 24 includes or accesses one or more sensors 122 to sense a characteristic of fluid that flows through the well choke and/or other characteristics apart from the fluid that flows through the well choke. The one or more sensors 122 measure pressure, velocity, mass flow rate, volumetric flow rate, viscosity, and/or other characteristics. For example, in certain instances, a sensor 122 is in the flow path upstream or downstream of the flow deflector, in the choke, in the wellbore (as shown) or elsewhere. The one or more sensors 122 are communicably coupled to the controller 120, allowing the controller 120 to operate the choke based on the output of the one or more sensors 122. The sensor 122 and the controller 120 can be coupled by wire or wireless connection. In certain instances, the controller 120 can operate in a closed loop feedback loop based on the output of the one or more sensors 122.

[0022] Certain aspects encompass, a surface well choke system includes a flow chamber and a fluid switch. The flow chamber includes a first flow chamber inlet that has more resistance to flow to an outlet than a second flow chamber inlet has to flow to the outlet. The fluid switch includes a first flow path from a fluid switch inlet to the first flow chamber inlet, a second flow path from the fluid switch inlet to the second flow chamber inlet, and a movable flow deflector upstream of the first and second flow paths that is actuable to deflect flow from the fluid switch inlet to the first flow path or the second flow path.

[0023] Certain aspects encompass, a fluid flow is directed from a wellhead through a first flow path of a surface well choke to an outlet of the surface well choke with a first flow resistance. A fluid deflector moves into the fluid flow and directs the fluid flow through a second, different flow path of the surface well choke to the outlet with a second, different flow resistance.

[0024] Certain aspects encompass, a surface well choke system includes a flow chamber and a fluid switch. The flow chamber includes a first flow chamber inlet that has more resistance to flow to an outlet than a second flow chamber inlet has to flow to the outlet. The fluid switch includes a first flow path from a fluid switch inlet to the first flow chamber inlet, a second flow path from the fluid switch inlet to the second flow chamber inlet, and a movable flow deflector upstream of the first and second flow paths that is actuable to deflect flow from the fluid switch inlet to the first flow path or the second flow path. A controller communicably coupled to an actuator of the movable flow deflector operates the actuator upon user input.

[0025] Implementations can include some, none, or all of the following features. The surface well choke system includes a controller communicably coupled to an actuator of the moveable flow deflector. The controller operates the actuator in encoding information as pressure pulses into fluid flowing through the surface well choke system. The controller operates the actuator at a specified duty cycle. The duty cycle includes rates of 0.001 to 1 Hertz. The movable flow deflector resides in an inlet flow path of the fluid switch, and the actuator stroke is 30% or less of the diameter of the inlet flow path. The surface well choke system includes a sensor to sense a characteristic of fluid that flows through the surface well choke system. The fluid switch includes a wellhead attachment flange. The first flow chamber inlet is an indirect flow inlet and the second flow chamber inlet is a direct flow inlet that is oriented to direct incoming flow more directly to the outlet than the indirect flow inlet. The flow chamber includes a curved sidewall apart from the outlet, where the indirect flow inlet is oriented to direct incoming flow substantially parallel to a tangent of the curved sidewall and the direct inlet is oriented to direct incoming flow at the outlet. The surface well choke system includes a bypass flow path to bypass flow around the flow chamber and the fluid switch, including an inlet about the inlet to the fluid switch and an outlet about the outlet of the flow chamber. The surface well choke system includes a second flow chamber and a second fluid switch in fluidic parallel to the first mentioned flow chamber and first mentioned fluid switch. Directing a fluid flow includes moving the fluid deflector in the fluid flow to an initial position and directing the fluid flow through the first flow path. The fluid deflector is cycled between an initial position and another position at a rate of 0.001 to 1 Hertz.

Directing the fluid flow through the second flow path includes directing the fluid flow through an indirect path to the outlet and directing the fluid flow through the first flow path includes directing the fluid flow through a more direct path to the outlet. A portion of the fluid flow is directed through a bypass while another portion of the fluid flow is concurrently directed through the first flow path or the second flow path. The surface well choke system includes at least one sensor communicably coupled to the controller to sense a characteristic of fluid that flows through the well choke system. The surface well choke system includes a first sensor upstream of the flow chamber to sense a first characteristic of fluid, and a second sensor downstream of the flow chamber to sense a second characteristic of fluid.

[0026] A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be. Accordingly, other embodiments are within the scope of the following claims.