Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore is drilled, various forms of well completions may be deployed downhole and positioned along one or more well zones. Flow control devices, such as flow control valves, may be utilized to control flow along the well completions. Many types of flow control devices are controlled by hydraulic actuating fluid delivered via control lines. However, pressure transients, e.g. pressure fluctuations, in the control line can detrimentally impact other hydraulically actuated devices located along the well completion.
In general, a system and methodology are provided for controlling fluid flow, e.g. fluid flow in a well. The control of fluid flow may be accomplished by utilizing a flow control valve which is selectively actuated via the controlled application of an actuating fluid. An isolation valve is positioned along the flow of actuating fluid at a location upstream of the flow control valve. The isolation valve establishes a preset pressure level, and the pressure of the supplied actuating fluid is raised above the preset pressure level to establish flow of actuating fluid to the flow control valve. The isolation valve also isolates detrimental pressure transients. For example, the isolation valve may be used to reduce or block the propagation of detrimental pressure transients along the actuating fluid to other controlled devices.
However, many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.
Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:
In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
The disclosure herein generally involves a system and methodology which facilitate various well operations or other operations by controlling fluid flow, e.g. controlling a primary fluid flow in a well. The control of fluid flow may be accomplished by utilizing a flow control valve which is selectively actuated via the controlled application of an actuating fluid. The actuating fluid may be the form of a hydraulic liquid delivered to the flow control valve via a control line. In a variety of well applications, a plurality of flow control valves may be located along a wellbore in different well zones. The individual flow control valves are actuated to control the flow of well fluid at the different well zones.
An isolation valve, e.g. a sequence valve, is used in cooperation with each flow control valve. For example, each isolation valve may be positioned along the flow of actuating fluid at a location upstream of a corresponding indexing device with respect to the supplied actuating fluid. The indexing device works in cooperation with a corresponding flow control valve. The isolation valve may be used to establish a preset pressure level. Pressure in the control line is raised above the preset pressure level to actuate the isolation valve and to thus enable flow of actuating fluid to the flow control valve. The isolation valve also may be used to isolate the actuating fluid within the control line from detrimental pressure transients. For example, the isolation valve may be used to reduce or block the propagation of detrimental pressure transients along the actuating fluid to other controlled devices, e.g. other flow control valves.
In an embodiment, a flow control assembly comprises a flow control valve and a sequence valve, the sequence valve having a reverse check valve. Flow control assemblies may be positioned along a well string for multi-zone flow control applications in which hydraulic fluid supplied by a hydraulic pump is used to actuate individual flow control valves in corresponding well zones. In this example, each flow control assembly comprises a flow control valve, an indexing device, e.g. a mini-indexer, and an isolation valve, e.g. a sequence valve, with a reverse check valve. Each sequence valve is installed upstream of the indexing device to isolate pressure transients introduced during actuation of a flow control valve, e.g. shifting of a flow control valve piston. Upstream refers to upstream along the supplied actuating fluid controlled by the isolation valve and used to selectively actuate the flow control valve.
Without the isolation/sequence valve, the onset of movement in a flow control valve during actuation of the flow control valve can effectively drawdown fluid and pressure in the control line. This drawdown can lead to undesired pressure fluctuations in other zones connected to the same control line. In some embodiments, the isolation valve may comprise a sequence valve having an inlet port, a reference pressure port, and an outlet port. The outlet port is placed in fluid communication with the inlet port when the inlet pressure exceeds a preset pressure level value relative to the reference pressure level.
In some applications, the mini-indexer or other suitable indexing device in each flow control assembly is used as a hydraulic switch which switches, for example, upon experiencing a pressure level or upon counting a predetermined number of pressure signals/pulses provided from the surface via the control line. In a multi-zone application, the indexing devices often do not make the switches at the same time due to differences between the indexing devices and differences in the well conditions at the various well zones. When one of the indexing devices switches, the hydraulic actuating fluid is suddenly exposed to a low-pressure region due to the shifting piston in the corresponding flow control valve. Without the isolation valve, this low-pressure region causes a corresponding pressure drop in the hydraulic system, including a pressure drop in the control line.
If the control line is exposed to the pressure drop and the pressure drop exceeds a certain value, other indexing devices could interpret the pressure drop as part of a surface control signal and count the actuation cycle incorrectly. Then, when the pressure in the control line recovers upon completing actuation of the corresponding flow control valve, the increase in pressure could be counted as the next actuation signal by other indexing devices. As a result, the actuation of a given flow control valve could initiate false indexing cycles counted by the other indexing devices coupled along the control line. In embodiments described herein, the isolation valve is constructed and located to block these false pressure cycles and other detrimental pressure transients from propagating along the control line to other pressure actuated devices, e.g. other indexing devices and flow control valves. Consequently, the specific flow control assemblies are actuated in a more consistent and dependable manner based on proper counting of pressure signals imposed by a surface pump and/or other pressure signal control system.
Referring generally to
In the embodiment illustrated, the isolation valve 42 comprises a reverse check valve 44 positioned to eliminate or reduce the false pressure pulses described above. Although isolation valve 42 may comprise a variety of valve configurations, the illustrated example utilizes isolation valve 42 in the form of a sequence valve 46. The isolation valve 42 comprises an inlet port 48, a reference pressure port 50, and an outlet port 52.
When the flow control valve 28 is to be shifted to a different operational position, the indexing device 40 is switched to a flow position via a pressure signal, e.g. a predetermined pressure level or number of pressure pulses, supplied via control line 38. For example, a surface pump may be used to provide the appropriate pressure signal. According to an example, when the pressure level supplied by control line 38 reaches a “switch pressure” of the indexing device 40, the indexing device 40 actuates and switches to a flow direction which allows actuating fluid to flow to flow control valve 28 and to actuate the flow control valve 28 via actuator 30. However, the isolation valve 42 is installed in hydraulic circuit 38 to establish a preset actuation pressure level, e.g. a preset actuation pressure which may be referred to as a preset sequence pressure. To enable the flow of pressurized actuating fluid to reach the indexing device 40, the preset sequence pressure of isolation valve 42 is first exceeded by increasing the pressure of actuating fluid supplied via control line 38. Exceeding the preset sequence pressure actuates the isolation valve 42 to an open flow position and thus allows the actuating fluid/pressure to reach the indexing device 40 and to flow through the indexing device 40.
In the example illustrated, the preset sequence pressure is established by a pressure differential between inlet port 48 and reference pressure port 50 of isolation valve 42. When the pressure at inlet port 48 relative to the reference pressure at reference pressure port 50 exceeds the preset sequence pressure, the isolation valve 42 is actuated. Once actuated, hydraulic fluid can pass through the isolation valve 42, through outlet port 52, through indexing device 30, and to flow control valve 28 so as to actuate the flow control valve 28.
During the process of actuating flow control valve 28, if the pressure upstream of the isolation valve 42 falls below the preset sequence pressure, the isolation valve 42 shifts to a closed position. Once the isolation valve 42 is closed, the pressure does not drop further in the control line 38, thus avoiding false pressure pulses. If the surface pump or other device providing pressurized actuating fluid along control line 38 continues to operate, the pressure upstream of the isolation valve 42 again rises to actuate the isolation valve 42, thus allowing pressurized actuation fluid to flow through indexing device 40 for actuation of the corresponding flow control valve 28 to a new actuation position. The reference pressure at reference pressure port 50 can be well pressure, a pressure related to well pressure, or another pressure established by a designated source.
Once the supply pressure of the actuating fluid supplied along control line 38 is removed, the higher pressure fluid downstream of the isolation valve 42 is released back to inlet port 48 through the reverse check valve 44. Consequently, the actuation of isolation valve 42 working in cooperation with reverse check valve 44 ensures that the unwanted pressure drops and other pressure transients do not propagate along the actuating fluid within control line 38. The reverse check valve 44, however, also enables controlled release of the downstream pressure so that the flow control assembly 26 may again be prepared for a subsequent actuation.
Referring generally to
When sequence valves 46 are employed in flow control assemblies 26, the cracking pressures of each sequence valve 46 in a given installation may be adjusted according to specific parameters. For example, the sequence valves 46 may be set collectively to actuate at roughly the same pressure. In other embodiments, however, the preset actuation pressure may be selected individually for each sequence valve 46 so as to enable a specific order of actuation with respect to the flow control assemblies 26 positioned along corresponding well zones 54. This latter embodiment can be helpful when bringing production or injection formations online in a prescribed fashion. Use of the specific order of actuation avoids undesirable pressure spikes in the well that could otherwise adversely affect the reservoir or equipment in the well string 22.
Referring generally to
When the inlet pressure at inlet port 48 is increased enough to overcome the force exerted by bias spring 62 and the pressure acting on reference pressure port 50, the sequence piston 60 is shifted (upwardly in the illustrated example). In other words, the pressure at inlet port 48 relative to reference pressure port 50 is increased above the preset actuation pressure for actuating sequence valve 46 and thus actuating flow control valve 28. Specifically, the shifting of piston 60 to an open flow position fluidly couples the inlet port 48 with the outlet port 52. This open flow position allows the pressurized actuating fluid to pass to flow control valve actuator 30 and to shift the flow control valve 28 to another operational position, provided the indexing device 40 has been indexed to an appropriate flow-through position.
If the pressure at the inlet port 48 drops a sufficient amount, the bias spring 62 moves piston 60 back to the position illustrated in
In some applications, the pressure drop at inlet port 48 may be caused by removing the supply pressure of the actuating fluid supplied along control line 38. At this stage, the higher pressure fluid located downstream of the sequence valve 46 is released back to inlet port 48 through the reverse check valve 44. Consequently, the reverse check valve 44 ensures controlled release of the higher pressure fluid downstream of the sequence valve 46 while protecting the upstream actuating fluid and control line 38 from unwanted pressure drops and other pressure transients.
According to some embodiments, the sequence valve 46 (or other type of isolation valve 42) comprises an adjustment mechanism 64 which may be used to adjust the force of spring 62 acting on piston 60. By adjusting the force of spring 62 acting on piston 60, the preset actuation pressure can be changed, e.g. lowered or raised, according to the parameters of a given application. The adjustment mechanism 64 also enables setting of different preset actuation pressures at different flow control assemblies 26 to facilitate the ordered actuation of flow control valves 28 at different well zones 54. In the illustrated example, the adjustment mechanism 64 comprises an adjustment screw 66 which may be threaded inwardly or outwardly to adjust the compression of spring 62 and thus the force exerted by spring 62 on piston 60.
In various well applications, the reference pressure port 50 may be in fluid communication with a well fluid. A protection mechanism 68 may be coupled with the reference pressure port 50 to protect the reference pressure port 50 from the well fluid, e.g. from pressure transients in the well fluid. As illustrated in
Depending on the application, the protection mechanism 68 also may comprise a compensated relief valve 74 coupled with the reference pressure port 50, as illustrated in
The flow control assembly or assemblies 26 may be used in a variety of well and non-well related applications. In various well applications, the flow control assemblies 26 may be used in cooperation with a pressure-pulse counting controller for selectively actuating flow control valves 28 at multiple well zones before. In many applications, the flow control assemblies 26 described herein provide a more predictable and reliable system which utilizes the dynamic pressure control provided by the sequence valves 46. The embodiments described herein also reduce flow control valve operation/shifting time especially for operations which use flow control valves 28 having relatively large stroke volumes.
Controlling the pressure transients also lowers risk of damage to choke seals during shifting of the flow control valves 28. Use of the reverse check valve 44 also prevents trapped pressures within the flow control valve assemblies. Reducing trapped pressures and undesirable pressure transients is beneficial in improving the reliability of many types of well systems, including intelligent, multi-zone flow control systems.
The overall well system 20 may have a variety of components and configurations. For example, the well system 20 may comprise numerous types of completions for use in a variety of well environments. Additionally, various numbers of flow control assemblies 26 may be used to control the flow of fluid with respect to a plurality of corresponding well zones 54. In production applications, the flow control assemblies may be used in combination with many other production completion components to control the flow of production fluid from the corresponding well zones 54.
Similarly, the individual flow control assemblies 26 may comprise various other and/or additional components. For example, various types of actuator pistons or other actuators may be used in the flow control valves 28, indexing devices 40, and/or isolation valves 42. Many applications utilize the indexing devices 40, but some applications may omit the indexing devices or use other types of controllable devices in cooperation with the corresponding flow control valve 28 and isolation valve 42 in each flow control assembly 26. Additionally, the materials used in constructing the flow control assemblies 26 as well as the size and configuration of the individual flow control assemblies 26 may vary according to the parameters of a given application.
Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.
The present document is based on and claims priority to U.S. Provisional Application Ser. No. 61/912,351, filed Dec. 5, 2013, which is incorporated herein by reference in its entirety.
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PCT/US2014/068747 | 12/5/2014 | WO | 00 |
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WO2015/085148 | 6/11/2015 | WO | A |
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Number | Date | Country | |
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20160319635 A1 | Nov 2016 | US |
Number | Date | Country | |
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61912351 | Dec 2013 | US |