WO2016061491A1 - Bi-metal flow control device - Google Patents

Abstract

A variety of flow control devices having a bi-metal component actuator for actuating the flow regulator valve and a method of use are described. The flow control regulator is activated by a pre-set design temperature bi-metal rings, plates, strips, rods and/or alternate designs The device's flow regulator utilizes this bi-metal component to actuate the flow regulation in response to temperature, and depending on the configuration, pressure.

Description

BI METAL FLOW CONTROL DEVICE

PRIOR RELATED APPLICATIONS

[0001] This application is a non-provisional application which claims benefit under 35

USC § 119(e) to U.S. Provisional Application Ser. No. 62/065,060 filed October 17, 2015, entitled "Bi-Metal Flow Control Device," which is incorporated herein in its entirety.

FEDERALLY SPONSORED RESEARCH STATEMENT [0002] Not applicable.

REFERENCE TO MICROFICHE APPENDIX [0003] Not applicable.

FIELD OF THE DISCLOSURE

[0004] The disclosure generally relates to flow control in a well and methods of use. Specifically, devices and methods for controlling produced fluid composition using the bi-metal effect to improve hydrocarbon recovery are described herein.

BACKGROUND OF THE DISCLOSURE

[0005] Canada and Venezuela have some of the largest deposits of a heavy oil called bitumen. Unfortunately, the bitumen is especially difficult to recover because it is wrapped around sand and clay, forming what is call 'oil sands.' Furthermore, the crude bitumen contained in the Canadian oil sands is described as existing in the semi-solid or solid phase in natural deposits. Bitumen is a thick, sticky form of crude oil, so heavy and viscous (thick) that it will not flow unless heated or diluted with lighter hydrocarbons. The viscosity of bitumen in a native reservoir is high. Often times, it can be in excess of 1,000,000 cP. Regardless of the actual viscosity, bitumen in a reservoir does not flow without being stimulated by methods such as the addition of solvent and/or heat. At room temperature, it is much like cold molasses. [0006] Conventional approaches to recovering heavy oils often focus on lowering the viscosity through the addition of heat. The two most basic processes used for recovering viscous oil from a formation include a "steam drive" process and a "huff and puff steam process. Steam drive involves injecting steam through an injection well into a formation. Upon entering the formation, the heat transferred to the formation by the steam lowers the viscosity of the formation oil, thereby improving its mobility. In addition, the continued injection of steam provides a drive to displace oil toward a production well from which it is produced. Huff and puff involves injecting steam into a formation through a well, stopping the injection of steam, permitting the formation to soak and then producing oil through the original well.

[0007] Another commonly used in-situ extraction thermal recovery techniques includes Steam Assisted Gravity Drainage (SAGD). SAGD is the most extensively used technique for in situ recovery of bitumen resources in the McMurray Formation in the Alberta Oil Sands (Butler, 1991) and other reservoirs containing viscous hydrocarbons. FIG. 1 displays the typical SAGD system. In a typical SAGD process, two horizontal wells are vertically spaced by 4 to 10 meters (m). The production well is located near the bottom of the pay and the steam injection well is located directly above and parallel to the production well. In SAGD, steam, generated by a e.g. Once-Through Steam Generator (OTSG), is injected continuously into the injection well, where it rises in the reservoir and forms a steam chamber. The steam heats the heavy oil, thus reducing its viscosity. The heated oil and condensed steam drain, through the use of gravity, to the production well. While FIG. 1 shows a single well pair, multiple pairs can be used throughout a reservoir.

[0008] It is often desirable to have a substantially even flow of steam along the injection path. An uneven flow increases steam breakthrough to the production well before the steam has an opportunity to heat the hydrocarbons in the reservoir. This, in turn, decreases the production of hydrocarbon because of the lack of heat transfer, the inefficient sweep of the steam, and the changes in reservoir porosity and pathways from repeated heat exposure.

[0009] Flow control devices (FCD) such as sliding sleeve valves, downhole safety valves, and downhole chokes are commonly used to control flow between the production tubing and the casing annulus. Such devices are used for zonal isolation, selective production, flow shut-off, commingling production, and transient testing. For instance, FCDs can be used to monitor production and shut down areas where water is being produced.

[0010] Fundamentally, all flow-control devices operate by the same mechanism: They provide an additional pressure drop at select points in the completion string to complement the pressure drop of fluid moving through the reservoir as well as internal pressure drops within the completion itself. FIG. 2 displays three of the more common geometries. In the frictional geometry, surface fiction is used to generate a pressure drop over a relatively long area. Typically, fluids flow through the large flow area of the device at a low velocity due to the friction. As such, the flow is viscosity sensitive, wherein more viscous fluids are slowed to a greater extend. The restrictive geometry uses fluid constriction to generate a differential pressure across the entire device. Thus, it's a small flow area with a higher velocity. Due the restrictive nature, there tends to be a partial viscosity insensitivity. For both the frictional and restrictive geometries, problems arise when undesired fluids breakthrough. Should an undesired fluid break through to these devices, the pressure drop across the FCD would be lower for the undesired fluid. Thus, the undesired fluid may be produced preferentially over desired hydrocarbons across the length of the production well.

[0011] The autonomous design improves upon the failings of the frictional and restrictive geometries. In this design, the device is able to passively adapt to changing downhole conditions in a way that controls unwanted fluids while preferentially producing desired fluids because it incorporates elements from both the restriction and frictional geometries.

[0012] Fluid breakthroughs, especially for steam, can still be an issue because FCDs typically control based on pressure (viscosity or velocity) or temperature, but rarely both. Complicated and expensive designs incorporating coil-tubing or control line activation based on downhole temperature observations have been developed, but their robustness is still questionable.

[0013] CA2813503 describes a flow control device for regulating the flow of steam and other fluids in the well system in response to temperature and pressure. The device has a flow regulator in communication with an actuator. The actuator contains a fluid substance that responds to any changes to a predetermined relationship between the phase of the fluid flowing through the flow control device and the temperature and pressure of the fluid and actuates flow through the regulator. In reservoir applications, one or more of these devices can be used on both the injector and producer wells to control fluid flow along the length of the formation. Thus, steam can be prevented from entering the producer wells.

[0014] Further improvements in controlling steam during all phases of heavy hydrocarbon recovery are desired. Preferably, the improvements offer a cheaper and more robust method of controlling steam or sub-cool drawdown over a range of temperatures.

SUMMARY OF THE DISCLOSURE

[0015] This disclosure presents a novel flow control device and method of use. Specifically, the flow control regulator is activated by a pre-set design temperature bi-metal rings, plates, strips, rods and/or alternate designs The device's flow regulator utilizes this bi-metal component to actuate the flow regulation in response to temperature, and depending on the configuration, pressure.

[0016] This FCD can be implemented to allow for the in-flow of reservoir fluids but restrict flow of sub-cool drawdown (the difference between the temperature of the injector or producer) to improve reservoir heat conformance, prevent the erosion of the linker, reduce the temperature within the producer well and improve energy efficiency (reduce S.O.R.). Embodiments to increase the flexibility of the operation temperature window pre-set by the chosen bi-metals are also described.

[0017] Flow regulators are integrated devices that are hard to segregate into specific components. For ease of understanding, flow regulators can best be explained by describing a flow regulator as consisting of a valve and an actuator of some sort. The bi-metal component in the present invention would be part of the actuator and may also include the valve portion, too.

[0018] In addition to the bi-metal component, the flow control device can also have a pressure compensation system that uses springs to shift the operating temperature window of the bi-metal regulator as to the steam phase condition curve. Thus, the presently describe flow control device is responsive to both pressure and temperature.

[0019] In another configuration, a duplex bi-metal component can be used as a pressure compensation system. At least one member of the duplex can have internal space under vacuum or containing a fluid, wherein the contents of the member would change the internal pressure differential that the member experience. This in turn can lead to greater expansion in response to pressure.

[0020] A method of using such flow control device is also disclosed. In particular, one or more flow control devices are placed external or internal to the production well to control the flow of produced fluid and restrict or prevent the breakthrough of steam.

[0021] In another embodiment, a series of any of the flow control devices mentioned above with differing characteristics are used to create a differential flow path along a production or injection well.

[0022] In yet another embodiment, a series of flow control devices placed concentrically around an inner production tube modulate flow of hydrocarbons entering the tube.

[0023] Heavy oil layers are repeatedly heated by steam, which can lead to formation damage and sand production. The reservoir porosity and permeability changes in response and large pore paths are created. Injected steam can enter these paths and penetrate the producer wells, without sufficiently heating the heavy oil. Thus, the steam breakthrough results in lower heat efficiency and smaller sweep volumes.

[0024] By slowing flow in areas where steam breakthrough occurs, the steam trap is maintained and maximum production occurs where steam breakthrough has not occurred. Differential flow along the production well allows the steam trap to remain consistent. Thus, the presently described FCD will allow for the preferential restriction of flow of the steam or water, as needed to maintain the desired steam flow. As such, these FCDs will decrease cost associated with steam breakthrough and improve overall SAGD performance. Furthermore, the simple design will be cheaper and more robust than currently available FCDs.

[0025] A flow control device is typically placed in the production string to create a pressure drop after the formation fluid enters the production string to maintain the fluid flow below the erosion velocity. However, flow control devices in the production string can also be used to control the type of fluid entering the production string. For instance, if a particular zone starts to produce mostly water, the flow control device may be completely closed in order prevent any fluid production from such a zone. Typically, such adjustments require human intervention and possibly retrieval of the flow control device from the reservoir. Production may also be shut down while the adjustments are made. Additionally, FCDs can be found between sand control media and production wells.

[0026] The bi-metal components in the flow regulators of the presently described flow control device have two metals with different temperature expansion properties. Thus, these devices can regulate flow in response to temperature of the fluid. No human intervention or production pause is needed because the adjustments are inherent to the chosen metals. Furthermore, springs can be used to shift the operating temperature window of the bi-metal regulators.

[0027] The bi-metal effect refers to the use of two metals, typically joined together as opposed to mixed together like alloys, have different rates of expansion when heated (or cooled). Thus, one metal will expand mush faster or to a larger degree than the second metal. A bi-metal component is capable of converting temperature changes into mechanical displacement. In the present FCD, this mechanical change is used to move a plunger up and down in an orifice in the outlet of the FCD. A spring in contact with the bi-metal component can also be used to shift the temperature window of the bi-metal component by requiring a great expansion, and thus higher temperature, to achieve the same mechanical displacement.

[0028] In addition to temperature response, pressure response is also possible. A spring with characteristics that parallel the steam envelop phase can be attached to the bi-metal component. For example, the bi-metal FCD can deflect "open" when it hits a certain temperature. There will be a pressure differential acting around the orifice that the device is plugging that will try to push a plunger into or out of the orifice. A spring can be used to bias this pressure one way or another. Alternatively, duplex bi-metal component can used, wherein one member of the component experiences internal pressure that will increase expansion.

[0029] In one embodiment, the bi-metal component is attached to a stopper valve. The stopper is lowered into an orifice in the outlet of the FCD to restrict or choke the flow of a higher temperature fluid. Lower temperature fluids will reduce the mechanical displacement of the bimetal regulator, thus raising the stopper and increasing flow through the orifice and outlet.

[0030] In another embodiment, the bi-metal flow regulator and plunger are oriented such that higher temperatures raise the plunger, allowing flow. Such an FCD would be beneficial for use on the inlet well during steam injection. Thus, in addition to controlling fluid being produced, the disclosed FCD can also be used to control injections of fluids and steam into the reservoir during the closed in startup period for e.g. SAGD.

[0031] Other regulator designs for covering the fluid inlet are possible including dimples and movable sealing rings.

[0032] In one embodiment of the present disclosure, one or more flow control devices using a bi-metal regulator are located on a production well, injection well or both. The bi-metal component expands when in contact with steam above a certain temperature limit to restrict flow of the steam into the production well. The bi-metal component contracts to increase flow when in contact with lower temperature fluid or steam. Thus, water and hydrocarbons are produced while steam breakthrough is limited.

[0033] In any of the above embodiments, a simple spring can be used to shift the temperature window of the bi-metal component. A simple spring with a spring constant and characteristics that follow the steam phase envelope may be used to apply force to the bi-metal component such that a greater expansion is needed to achieve the same flow response. Thus, the bi-metal component may start to move the plunger in the open direction at 100°C. But, if an additional spring is pushing the stopper in the closed direction with a force of xKg, then the bi-metal component has to reach a higher temperature than 100°C to start the stopper moving off the closed position. Such springs can be sized to apply a given bias (positive or negative) to what the bi-metal component delivers; this will shift the opening temperature for the regulator valve.

[0034] In yet another embodiment, a duplex bi-metal component can be used to actuate pressure and temperature.

[0035] Furthermore, methods of using any of the above flow control devices are also presented. In one aspect of the disclosure, flow is controlled by flowing a fluid through one or more flow control devices in a well system; allowing the bi-metal regulator to adjust to the differences in temperature and pressure interior and exterior to the device; and restricting or increasing flow in response to the temperature or pressure differential.

[0036] Typically, the FCD allows liquids or hydrocarbons to pass but closes, reduces flow, or restricts flow when hotter fluids or steam come in contact with the FCD. The flow control devices in the present disclosure can be along the production tubing, or injection tubing, or both, and/or limit steam vapor passage relative to liquids. The devices can he attached to the exterior or interior of the wells, casings, tubings, and the like.

[0037] In the present device, the flow regulator can have rings, plates, strips, rods, tubes and other designs composed of two metals bonded together in one or more layers as components of the actuator. Additionally, a tube with an internal space for holding a fluid can be used as one of the bi-layers, with the second layer being a concentric tube layer.

[0038] Any metal combination can be used; however, due to the environmental conditions in the well, softer metals such as alkali and alkaline metals are not preferred, unless utilized in an alloy. Preferably, transition metals, post-transition metals, and lanthanides are preferred. Certain alloys such as steel, bronze, brass and the like, can be used as one of the two metals in the FCD. Typical metal combinations include steel and copper; steel and brass; and, copper and iron. Other metals can be nickel, zinc, lead, silver, cadmium, aluminum, chromium, tungsten, iridium, platinum, and gold.

[0039] The actuator has at least one bi-metal member of the bonded metals. However, one to 10 bi-metal members can be used, preferable 2-8, and most preferable, 2-4 bi-metal members of the same bonded metal are used for each bi-metal component. The bi-metal members can be alternating layers or can have concentric designs. Alternatively, different geometries can be utilized by each member.

[0040] In addition to a temperature response, a pressure response is also possible. The bimetal component can be attached to a plunger or stopper that plugs an orifice. There is a pressure differential across the orifice that is either trying to push the plunger or stopper into or out of the orifice. By placing a simple spring on the bi-metal component, a bias can be added to the pressure differential across the orifice. Thus, a greater expansion or contraction of the bi-metal component with a spring would be needed to achieve the same plunger movement than a bimetal component without a spring.

[0041J Ideally, the spring would have characteristics that result in paralleling of the steam phase envelop. Though less sophisticated, this would be a cheap and robust method of shifting the operating temperature of the bi-metal component. [0042] A duplex bi-metal component is also envisioned, wherein the two members have different metals or geometries that allow for a temperature and pressure based response. At least one member must have an open internal space that can either be under vacuum or contain a fluid. The contents of the internal space change the internal pressure differential that the member experiences thus increase expansion.

[0043] The presently disclosed device is described with reference to a hydrocarbon recovery application, specifically heavy oil or bitumen recovery. However, the FCD can be used in any application requiring flow control, wherein the fluid has temperature or pressure differentials and there exists a desire to control fluid composition.

[0044] As used herein, the term "FCD" includes any device that restricts significant flow of steam vapor into the production well by causing an increased pressure drop with localized high flow rate, or by discriminating between live steam vapor and liquid water or oil such that live steam vapor is met with much higher pressure drop or other throttling measures.

[0045] As used herein, the terms "production well" or "producer" are used interchangeable to mean a well used to retrieve hydrocarbons from an underground reservoir.

[0046] As used herein, the term "bi-metal" refers to two metals layers or a metal and alloy layers or two alloy layers that are joined, bonded, or sandwiched together as opposed to mixed. In components with multiple bi-metal layers, each layer is referred to as a "member." A "bimetal component" can have one or more members.

[0047] As used herein, the term "open" is used to mean that flow is not restricted or is partially restricted through the outlet of the FCD, thus allowing flow. "Closed" refers to no flow exiting the outlet of the FCD.

[0048] The use of the word "a" or "an" when used in conjunction with the term "comprising" in the claims or the specification means one or more than one, unless the context dictates otherwise.

[0049] The term "about" means the stated value plus or minus the margin of error of measurement or plus or minus 10% if no method of measurement is indicated.

[0050] The use of the term "or" in the claims is used to mean "and/or" unless explicitly indicated to refer to alternatives only or if the alternatives are mutually exclusive. [0051] The terms "comprise", "have", "include" and "contain" (and their variants) are open- ended linking verbs and allow the addition of other elements when used in a claim.

[0052] The phrase "consisting of is closed, and excludes all additional elements.

[0053] The phrase "consisting essentially of excludes additional material elements, but allows the inclusions of non-material elements that do not substantially change the nature of the invention.

[0054] The following abbreviations are used herein:

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] FIG. 1. is a schematic of a SAGD well pad. [0056] FIG. 2. Types of flow control devices.

[0057] FIG. 3. displays a bi-metal component of the regulator according to one embodiment, wherein a plunger is raised and lowered in response to temperature and/or pressure dependent changes in the bi-metal.

[0058] FIG. 4. displays a bi-metal flow control device according to one embodiment, wherein a spring is utilized to shift the pre-set temperature window of the bi-metal component.

[0059] FIG. A-C display exemplary bi-metal flow control devices that attached external to the production tubing wherein 5 A is a moveable sealing ring, 5B is a dimple and 5C is a spring/plunger assembly.

[0060] FIG. 6A-C displays a concentric design using multiple FCDs to control flow entering an inner base pipe. FIG. 6A shows a side view of the schematic of the assembly and an end view showing the orifices; FIG. 6B displays the FCD washer having fasteners/studs and choke plungers; FIG. 6C shows the plungers when opened and closed. DETAILED DESCRIPTION

[0061] The disclosure provides a novel flow control device utilizing bi-metal components to allow flow for fluids while restricting or inhibiting the flow of steam. Additionally, methods of use such flow control devices are disclosed.

[0062] Heavy oil recovery is often hindered by the soft oil sands in the formation. Because the sands can plug the production well, sand control tools, such as slotted liners or tubing, and screens are used to prevent the sands from entering the production tubing. Flow control devices are often placed in the annulus between the sand control tools and the production tubing to control flow for e.g. zonal isolation, selective production, flow shut-off, commingling production, and transient testing. Thus, the fluids in the reservoir move from the reservoir to the annular space to the FCD before entering the production tubing and being produced. This allows for a more even flow of production fluids and helps to create a pressure drop such that the fluid does not exceed the erosion velocity.

[0063] In addition to controlling the fluid velocity, the FCDs can also be used to control the type of fluids entering the production tubing. For instance, if a particular zone starts to produce mostly water, the flow control device may be completely closed in order prevent any fluid production from such a zone.

[0064] In the presently disclosed FCD, a bi-metal flow regulator is used to control the velocity of the fluid and the type of fluid that can enter the production tubing. Specifically, the FCD has an inlet for introduction of fluids in the annular space and an outlet for fluids flowing into the inner production tubing. The outlet has a narrowed orifice containing a plunger. The plunger is attached to a bi-metal flow regulator, wherein the metal layers are alternating. The metal layers have different rates of expansion. Thus, when the flowing fluids exceed a certain temperature, the regulator will increase in size and force the plunger into the orifice, thus closing off flow in the outlet. Below a certain temperature, the metals contract such that the plunger is no longer restricting flow through the orifice and out of the FCD. The FCD also has a means of attaching to the production tubing and/or the casing or liners.

[0065] The FCD may also have an optional spring system that can shift the operating temperature window of the bi-metal flow regulator, such that the regulator is in line with the steam phase condition curve. The optional spring system will then allow the bi-metal flow regulator to adjust in response to pressure changes of the flowing fluid.

[0066] The FCD can also have a duplex bi-metal component wherein at least one member has an internal space that can be under vacuum or filled with a fluid and is capable of experienced variations in internal pressure that can enhance expansion.

[0067J The FCD's described herein are advantageous in oil recovery methods utilizing steam. Water and hydrocarbons at lower temperatures will be capable of flowing through the FCD to the production tubing, whereas the higher temperature and pressure steam will be restricted. This will prevent steam breakthrough in the production wells.

[0068] A method of using the disclosed bi-metal FCD is also described. In one embodiment, one or more FCDs are attached externally to the inner production tube. The fluid in the annular space is allowed to flow through the FCDs, wherein the bi-metal regulator adjust in response to temperature and/or pressure of the fluid. The plunger attached to the regulator moves into the orifice, thus reducing flow if the bi-metal regulator expands or the plunger recedes from the orifice, thus increasing flow if the bi-metal regulator contracts. The fluid, if allowed to flow, exits the FCD through the outlet and enters the production tubing to be produced.

[0069] In yet another embodiment, one or more FCDs are attached to the production well, the injection well, or both. For the injection well, the FCD can be configured such that only hot fluids, such as steam are allowed to flow.

[0070] FIG. 3 displays a bi-metal regulator component of the regulator in the FCD according to one embodiment. Such a component would have geometries designed to fit within a small upset area that is preferable concentric to a base pipe. The entire FCD can be mounted on the pipe, much like the autonomous flow geometry in Fig. 2. Alternatively, it can be in the tubing. If sand control media is utilized, the FCDs can be integrated with the sand control or completely separate with the sand control media in the liner and the FCD in the tubing. The appropriate placement of the device will depend on the reservoir character and production design.

[0071] Fluid flows from the reservoir into the FCD via the inlet. The bi-metal flow regulator responds to the temperature by either expanding or contracting, which each metallic layer responding at a different rate or to a much greater degree. Table 1 displays the thermal expansion rate for exemplary metals that can be used in the present FCD. Different regulating conditions can be obtained by selecting appropriate materials or combinations of materials to fit the expected reservoir temperature profile.

[0072] The bi-metal flow component in FIG. 3 converts the temperature changes into a mechanical change during expansion. A plunger connected to the flow regulator is then capable of being moved up and down in an orifice on the outlet. For hot fluids, such as steam, the regulator expands, pulls the plunger into the orifice to close the outlet. Thus, FCD is closed against steam. When cooler fluids, such as hydrocarbons or water, enters the FCD, the flow regulator will contract, thus lowering the plunger and opening the orifice to resume flow.

[0073] While FIG. 3 shows restrictive orifice geometry, this is not necessary. The design could be such that all throttling is due to the position of the plunger much like a common water faucet. In this case, the orifice can be larger and, when the plunger is fully open, the orifice does not by itself restrict flow. However, it may be quite appropriate to have a fully open plunger still result in some pressure drop that limits maximum flow rate through the device. In general, the design of the inlet and outlets is not required to have material pressure restriction; but, depending on the reservoir, there may he merit in using inlet and outlet pressure drops to act in concert with the variable pressure drop by the device to obtain the overall pressure response from the system.

[0074] One or more of the devices in FIG. 3 can be located on the production well. Though not shown, the device in FIG. 3 can have means of attaching to both the external wall of the production well or the internal wall of the sand control media.

[0075] The configuration of the bi-metal flow regulator can be varied depending on the temperature of preferred fluids. FIG. 3 displays a configuration for restricting the flow of steam into a producer well. However, the device can be configured to pass steam condensate as opposed to steam vapor. The sizing of the orifices when fully open could be used to discriminate against very high flow velocity (vapor phase) as oppose to the same mass flow in liquid phase.

[0076] A potential variation is to replace the sub-orifice plunger with a stopper that rests above the orifice. Thus, upon expansion, the bi-metal flow regulator could raise the stopper, thus opening the orifice for flow. Upon contraction of the bi-metal regulator, the stopper can be lowered to cover the orifice. Alternatively, simply flipping the bi-metal flow regulator of FIG. 3, 180 degrees may allow for the plunger to be lowered upon expansion, thus opening the orifice to flow.

[0077] Another embodiment of the present FCD is shown in FIG. 4, wherein one or more springs are used to shift the temperature window of the bi-metal component. In such a design, the spring prevents the expansion of the bi-metal component from mechanically displacing the plunger or stopper. Thus, a higher temperature and greater expansion is needed to achieve the same displacement. For example, the bi-metal component may start to move the plunger or stopper in the open direction at e.g. 100°C as the spring is pushing the stopper or plunger in the closed direction with a force of xKg. Thus, the bi-metal component has to reach a higher temperature than 100°C to start the stopper or plunger moving off the closed position. Such springs can be sized to apply a given bias (positive or negative) to what the bi-metal component delivers; this will shift the opening temperature for the regulator valve.

[0078] In addition to temperature response, the bi-metal component can be adapted to respond to pressure, too using a duplex bi-metal component. In a duplex bi-metal component can be used wherein one bi-metal member actuates pressure and the second bi-metal member actuates temperature. For instance, copper expands more than iron with increasing temperature. A copper tube (or capsule) also expands more with internal pressure increases than a steel tube of the same diameter, wall thickness, etc. Thus, by choosing the right thermal expansion coefficients for two metals and the right tube geometries, we should be able to create a deflection that is depend on both temperature and pressure to achieve the throttling "on/off" actuation of the plunger or stopper.

[0079] The same dual actuation effect can be achieved with disks, spheres and other geometries besides tubes, particularly geometries with an empty internal space. The contents of the internal space can be under vacuum and/or contain fluids such as water to change the internal pressure differential that the tubes, disks, spheres, etc experience. Any fluid can be used in this internal space.

[0080] Additionally, one member of the duplex design can be solid while the second member has the internal space to create the desired internal pressure differential.

[0081] Alternatively, the spring design in FIG. 4 can also be used to bias the pressure of the plugger being pushed into or out of the orifice. Thus, a greater bi-metal expansion would be needed to overcome the springs' pressure.

[0082] FIG. 5 illustrates different bi-metal regulator shapes that can be used to regulate flow through the fluid portal on a production tubing and shows both the open and closed (sealed) positions. In FIG. 5A, a bi-metal spring attached to a sealing ring circles the production tubing. Upon expansion of the bi-metal spring, the sealing ring moves to partially or fully cover the fluid portal. [0083] FIG. 5B and 5C show regulators anchored to the outer production pipe or screen. Thermal or pressure expansion of the bi-metal dimple in FIG. 5B partially or fully covers the fluid portal. The thickness of the two layers can be the same or different depending on the characteristics of the chosen metals. Alternatively, the bi-metal dimple can also have an outer layer coating akin to the sealing ring in FIG. 5 A. Such a coating would improve seal quality over the metal layer.

[0084] In FIG. 5C, a bi-metal spring attached to a plug expands from the outer production pipe or screen to cover the fluid portal. This plug design provides a more seal-tight fit than the sealing ring by filling the portal.

[0085] While the above methods describe use of one regulator, it is possible to have multiple regulators on a production well.

[0086] FIG. 6 contemplates a series of regulators concentric to the production tubing as controlling the flow. The inner base pipe and outer sleeve are separated by webbing and have a washer or annular ring connecting to the inner and outer sleeve. Two or more orifices are drilled into the washer between the inner and outer sleeve to allow flow through the washer, as illustrated in the end view of the washer in FIG. 6A. A second bi-metal washer or ring, FIG. 6B, has choke plungers that align with the orifices on the washer and a series of fasteners or stubs to connect the bi-metal sleeve to the washer and/or inner or outer sleeves and webbing. As shown in the side view in FIG. 6A, fluid flows through the outer sleeve into the webbing and through the orifices before entering the inner base pipe via fluid portals. The choker is open during flow of cool fluids, but seals the orifices quickly upon expansion of the bi-metal washer when contacted with heated fluids, FIG. 6C.

[0087] A series of devices with varying characteristics can also be used to create a differential flow along the production well. Or, alternatively, the same bi-metal composition combined with springs of varying stiffness can be used. While it is expected that a single bi-metal FCD can provide suitable steam trap control, it may be beneficial and more cost-effective under certain reservoirs conditions to enhance flow control using multiple devices. For instance, the stopper or plunger of the presently described FCDs can be wide-open until temperature gets close to the steam saturatio conditions and then it closes completely while a second FCD, or restrictor within the same FCD, that is more suitable for throttling over the narrower range of the steam phase change envelope takes over the flow control function.

MODELING

[0088] Modeling will be performed to determine how effective the disclosed FCD is in enhancing SAGD. Steam drive development models are common in the oil and gas industry. Such models are built using real reservoir characteristics obtained from geological surveys and the like. Modeling programs such as Computer Modeling Group Ltd STARS™ allow for building of a model of the reservoir and a simulation of a e.g. steam injection. Formation of the steam chamber and potential steam breakthough in the production well will be modeled with and without the FCD disclosed. Such results are expected to show that the presently disclosed FCD decreases the amount of steam allowed to enter the production well.

[0089] Although the systems and processes described herein have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the spirit and scope of the invention as defined by the following claims. Those skilled in the art may be able to study the preferred embodiments and identify other ways to practice the invention that are not exactly as described herein. It is the intent of the inventors that variations and equivalents of the invention are within the scope of the claims while the description, abstract and drawings are not to be used to limit the scope of the invention. The invention is specifically intended to be as broad as the claims below and their equivalents.

[0090] The following references are incorporated by reference in their entirety.

[0091] US7866400, US8096362, CA2813503, Steele, et al. "Phase-Controlled Well Flow Control and Associated Methods"

Claims

1. A flow control device for use in a subterranean well system, comprising: a) an enclosed space having an inlet and an outlet having an orifice, wherein said orifice opens into a production tube and said inlet opens into a subterranean reservoir; b) a flow regulator inside said enclosed space, wherein said flow regulator controls flow through said orifice; and, c) an actuator connected to said flow regulator and inside said enclosed space, said actuator having a bi-metal component, wherein said bi-metal component has at least one member of the two metals, wherein said actuator actuates the flow regulator in response to temperature changes.

2. An improved production well, said production well having a inner production tubing having at least one fluid portal and an outer sleeve separated from inner production tubing by webbed material, said improvements comprising: a) at least one flow regulator inside said webbed material, wherein said flow regulator controls flow through said fluid portal; and, b) at least one actuator connected to said flow regulator and inside said enclosed space, said actuator having a bi-metal component, wherein said bi-metal component has at least one layer of the two metals, wherein said actuator actuates the flow regulator in response to temperature and/or pressure changes.

3. A well system comprising a flow control device to regulate the flow of a fluid between an exterior and interior of a production well via a fluid portal, said flow control device having a bimetal component that responds to temperature on the exterior of the production well and a flow regulator in contact with said bi-metal component, wherein said bi-metal component actuates said flow regulator to prevents flow of the fluid above a certain temperature through said fluid portal between the exterior and the interior of the production well.

4. A flow control device for use in a subterranean well system, comprising: a) an enclosed space having an inlet and an outlet having an orifice, wherein said orifice opens into a production tube; b) a flow regulator inside said enclosed space, wherein said flow regulator controls flow through said orifice; and, c) an actuator connected to said flow regulator and inside said enclosed space, said actuator having two bi-metal components, i) wherein at least one bi-metal component has an internal space filled with a fluid, ii) wherein the internal pressure experienced by said internal space of at least one bi-metal component is dependent on said fluid's expansion in response to temperature such that the bi-metal component expands or contracts in response to external temperature and internal pressure; iii) wherein said bi-metal components actuate the flow regulator.

5. A flow control device for use in a subterranean well system, comprising: a) an enclosed space having an inlet and an outlet having an orifice, wherein said orifice opens into a production tube; b) a flow regulator inside said enclosed space, wherein said flow regulator controls flow through said orifice; c) an actuator connected to said flow regulator and inside said enclosed space, said actuator having a bi-metal component, wherein said bi-metal component has at least one layer of the two metals, wherein said actuator actuates the flow regulator in response to temperature changes; and d) a spring attached to said bi-metal component and a side of said enclosed space, wherein said spring hinders the actuation of said flow regulator by said actuator.

6. A flow control device for use in a production well, wherein said production well has an outer sleeve screen surrounding an inner base pipe, said flow control device comprising: a) an annular ring with at least two orifices, said annular ring connecting said outer sleeve screen and inner base pipe; b) a ring-shaped bi-metal actuator with at least two choke plungers aligned with said orifices of said annular ring; and c) one or more fasteners on said ring shaped bi-metal actuator to attach said ring shaped bimetal actuator to said annular ring.

7. A method of controlling fluid content in a production well during hydrocarbon production, wherein said production well has a flow control device attached to a fluid portal on said production well, said method comprising: a) introducing a fluid from a hydrocarbon-containing reservoir into said flow control device, wherein said fluid control device has a bi-metal component attached to a flow regulator having a plunger, wherein said plunger is capable of closing said fluid portal; b) adjusting bi-metal component to temperature of said fluid, wherein said bi-metal component expands at high temperatures and contracts at low temperatures; c) actuating said plunger in response to the mechanical movement of said bi-metal component, wherein when said bi-metal component is expanded, the plunger restricts or closes the outlet of said flow control device, wherein when said bi-metal flow regulator is contracted, the plunger opens the outlet of said flow control device; and d) restricting or increasing flow of said fluid from flow control device to said production well.

8. A method of controlling fluid content in a production well during hydrocarbon

production, wherein said production well has a sand control media external and concentric to said production well, an annular space between said production well and said sand control media, and a flow control device in said annular space, said method comprising: a) flowing fluid from a hydrocarbon-containing reservoir through said sand control media and into said annular space; b) introducing said fluid into said flow control device, wherein said fluid control device has a bi-metal component attached to a flow regulator, wherein said flow regulator is capable of closing an outlet of said flow control device; c) adjusting bi-metal component to temperature of said fluid, wherein said bi-metal component expands at high temperatures and contracts at low temperatures; d) actuating said flow regulator in response to the mechanic movement of said bi-metal component, wherein when said bi-metal component is expanded, the flow regulator restricts or closes the outlet of said flow control device, wherein when said bi-metal flow metal is contracted, the flow regulator opens the outlet of said flow control device; and e) restricting or increasing flow of said fluid from flow control device to said production well.

9. The improvement of one of claims 1 - 8, wherein said flow regulator is a plunger, a choke, a sealing ring or a stopper.

10. The improvement of one of claims 1 - 9, wherein said bi-metal component is a rod, a rectangle, a ring, a tube, a curved strip or a plate.

11. The improvement of one of claims 1 - 10, wherein said bi-metal component has 2 to 8 members.

12. The improvement of one of claims 1 - 11, further comprising a plurality of flow control devices evenly spaced around said production well.

13. The improvement of one of claims 1 - 12, wherein said bi-metal component is composed of two metals with different thermal expansion rates.

14. The improvement of one of claims 1 - 13, wherein said bi-metal component is comprised of transition metals, post-transition metals, and lanthanides.

15. The improvement of one of claims 1 - 14, wherein said bi-metal component is composed of two metals, wherein at least one metal is a steel, bronze or brass alloy.

16. The improvement of one of claims 1 - 15, further comprising a spring attached to said bimetal component and a side of the enclosed space, wherein said spring affects the actuation of said flow regulator.

17. The improvement of one of claims 1 - 16, wherein said flow control device is attached to either the interior of a screen or the exterior of a production well in said subterranean well system or both.

18. The improvement of one of claims 1 - 17, further comprising a spring attaching said bimetal component to the wall of said flow control device, wherein said spring affects the actuation of said flow regulator.

19. The improvement of one of claims 1 - 18, said flow control device further comprising at least one spring attach to said bi-metal component and a side of said flow control device such that said mechanical movement of said bi-metal component is impeded by said spring.