System and method for controlling actuation of tools in a wellbore

A technique is provided to control operation of well tools deployed in a wellbore. The technique utilizes a completion with at least one well tool actuated by fluid input. An electronic trigger system is associated with each well tool and is designed to respond to a unique series of pressure pulses. Upon receiving the unique series of pressure pulses, the electronic trigger system actuates to enable flow of actuating fluid to the well tool for operation of the well tool.

BACKGROUND

Various subterranean formations contain hydrocarbon based fluids that can be produced to a surface location for collection. Generally, a wellbore is drilled, and a completion is moved downhole to facilitate production of desired fluids from the surrounding formation. In many applications, the wellbore completion includes a hydraulic tool that is actuated by hydraulic pressure applied, for example, in the annulus surrounding the tool.

Actuation of the hydraulic tool often is controlled by using a rupture disk placed in the flow path of the hydraulic fluid that would otherwise actuate the hydraulic tool. In other words, the rupture disk is used to avoid premature actuation before a predetermined level of pressure is applied in the annulus. Once sufficient pressure is applied, the disk ruptures to create a flow path for hydraulic fluid to flow into and activate the hydraulic tool. In applications with multiple hydraulic tools, rupture disks which rupture at different pressure levels can be used to provide some individuality as to actuation of the hydraulic tools. Pressure levels within the annulus or completion tubing can be controlled by pumps disposed at a surface location.

When rupture disks are used, however, the hydraulic tool having the disk with the lowest pressure setting is always the tool that must be actuated first. Additionally, each rupture disk requires approximately a 500-1000 psi window for rupture. Thus, if multiple hydraulic tools are to be actuated at different times, multiple pressure ranges are required across a potentially large pressure spectrum. For example, if seven different rupture disks are used in a completion, a 7000 psi window above the normal hydrostatic pressure is required for dependable actuation of the corresponding hydraulic tools at the desired times.

SUMMARY

In general, the present invention provides a system and method for actuating tools used in a wellbore. One or more well tools are utilized in a completion and subject to actuation by application of a fluid through, for example, the annulus, a completion tubing or a dedicated supply line. Additionally, each well tool cooperates with an electronic trigger system designed to selectively enable flow of actuating fluid to a specific tool of the one or more well tools. The electronic trigger system is selectively actuated via a unique series of pressure pulses.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

The present invention relates to facilitating the use of a variety of wellbore completions having one or more well tools that may be actuated by a fluid. Generally, a completion is deployed within a wellbore drilled in a formation containing desirable production fluids. The completion may be used, for example, in the production of hydrocarbon based fluids, e.g. oil or gas, in well treatment applications or in other well related applications. In many applications, the wellbore completion incorporates a plurality of well tools that may be individually actuated at desired times. In the embodiments described below, individual electronic trigger systems are operatively coupled to corresponding well tools to enable this selective actuation of each tool.

Referring generally toFIG. 1, a well system20is illustrated as comprising a completion22deployed for use in a well24having a wellbore26that may be lined with a wellbore casing28. Completion22extends downwardly from a wellhead30disposed at a surface location32, such as the surface of the Earth or a seabed floor. Wellbore26is formed, e.g. drilled, in a formation34that may contain, for example, desirable fluids, such as oil or gas. Completion22is located within the interior of casing28and comprises a tubing36and at least one device38, e.g. well tool, that is actuated by a fluid. In the embodiment illustrated, completion22has four devices38. Depending on the design of wellbore completion22, the actuating fluid can be directed to the well devices38through an annulus40surrounding completion22, through tubing36, or through a dedicated fluid conduit. In many applications, the actuating fluid is a hydraulic fluid, and devices38are hydraulically actuated. However, devices38also can be of the type used in a gas well and actuated by gas pressure.

Each device38is cooperatively associated with a corresponding electronic trigger system42. In the embodiment illustrated, for example, four electronic trigger systems42are associated with the four devices38however other numbers of devices and the corresponding electronic trigger systems can be used depending on the completion design. Each electronic trigger system42is dedicated to a specific well device38, e.g. to a specific well tool. The electronic trigger systems42enable the selective actuation of each individual device38when desired by the well operator. The electronic trigger systems block the flow of actuating fluid, e.g. hydraulic fluid, to the corresponding devices until it is desired to actuate the device, and thus the systems can be used with a variety of well devices. Examples of well devices38include, but are not limited to, samplers (e.g. a DST annular sampler), packers (e.g. a hydrostatic set packer), valves (e.g. a formation isolation valve, a bypass valve in a gravel-pack wash pipe, a ball valve, a DST reversing valve, or a flapper valve), gravel pack service tools (packers, releasing subs, circulating and reversing tools), tools used in tubing conveyed perforated devices, gun anchors or run releasing tools.

Referring now toFIG. 2, an embodiment of one of the electronic trigger systems42is illustrated. In this embodiment, electronic trigger system42comprises a valve44that may be selectively moved from a closed position to an open position to enable the flow of actuating fluid to well tool38. As illustrated, valve44is cooperatively engaged with well tool38via a fluid control line46coupled to the electronic trigger system42by a control line adapter48. When valve44is in an open position, the actuating fluid can flow from a supply source external of the electronic trigger system42, e.g. fluid disposed in annulus40, through fluid control line46and into well tool38via an inlet port50for actuation of the tool. In some embodiments, well tool38may comprise a rupture disk52located in port50, the rupture disk being designed to rupture upon the opening of valve44and the flow of, for example, hydraulic actuating fluid to tool38. It also should be noted that in some system designs electronic trigger system42may be coupled directly to well tool38.

Each electronic trigger system42further comprises an actuator54for selectively moving valve44between the closed position and the open position. In this embodiment, actuator54is operated in response to a unique pressure pulse signal detected at the electronic trigger system42by a pressure sensor56. An electronics system58is used to decode the pressure pulse signal detected by pressure sensor56and also to initiate actuation of actuator54when the specific, predetermined pressure pulse signal is received. Power for the electronic system58and for the low power actuator54is supplied by an internal power source60formed by, for example, a battery or batteries62.

In one embodiment, electronic system58may be constructed as a microprocessor-based system for control logic, as known to those of ordinary skill in the art. This type of system effectively enables downhole computer recognition of the unique signature of the pressure pulse signal associated with actuation of a specific hydraulic tool38. The pulses are detected by pressure sensor56and decoded by electronics system58which then implements the command and control operation of actuator54to enable flow of actuating fluid to tool38.

The components of electronic trigger system42may be assembled in a space efficient manner, depending on the specific design of the overall system20. In the illustrated embodiment, pressure sensor56, power source60, electronic system58, actuator54and valve44are assembled in a generally elongate body64. For example, elongate body64may be generally cylindrical in shape with a relatively small diameter to facilitate deployment in a variety of locations, such as along completion22. For example, elongate body64may be positioned along an exterior or an interior of completion22, in the wall of completion22, along an exterior or interior of well tool38, or in the wall of well tool38. In the example illustrated, elongate body64is generally cylindrical and has a diameter of less than 1 inch, e.g. a diameter of approximately 0.875 inch or less.

An example of a pressure pulse signal66having a unique series of pressure pulses68is illustrated graphically inFIG. 3. The profile of pressure pulse signal66is selected such that the profile cannot occur during the life of the well other than when deliberately generated by, for example, surface pumps used to send the coded low-level pressure pulses through annulus40. The pulses do not all have to be of the same amplitude or duration. The amplitude of the pulse, the duration and the number of pulses can be varied to obtain a unique series of pressure pulses. Pressure pulses68are detected by pressure sensor56, and electronic system58is used to decode the overall pressure pulse signal66. After the pressure pulse signal66has been decoded and found to be of the correct predetermined shape, e.g. as illustrated inFIG. 3, electronic system58causes actuator54to open valve44, thereby enabling the flow of actuating fluid through inlet port50for actuation of well tool38. By way of example, the flow of fluid may be a flow of hydraulic fluid to actuate a hydraulic tool38, but it also can be a flow of high-pressure gas for actuation of a tool38deployed in a gas well. In the latter case, a gas system tubing and rat hole can be used to hold formation gas and/or nitrogen gas. Once the electronic trigger system is actuated, the corresponding well tool38is actuated by gas pressure in the well.

If a plurality of electronic trigger systems42are used in the completion22(seeFIG. 1in which completion22utilizes four hydraulic tools38and four electronic trigger systems42), then each well tool38is associated with its own specific pressure pulse signal that is unique with respect to the specific pressure pulse signals associated with the other tools of the completion. Accordingly, each electronic trigger system is individually addressable without the need for separate, sequentially increasing pressure ranges. By way of example, the pressure pulse signal66ofFIG. 3would be associated with one electronic trigger system42and corresponding well tool38, and other unique pressure pulse signals would be associated with each of the other electronic trigger systems and corresponding tools. One way of making the pressure pulse signals specific or unique with respect to each electronic trigger system is by changing the time period between pulses. For example, the time period between the last two pulses can be changed from one trigger system to the next, and electronic system58can be programmed to recognize these unique pressure pulse signals.

Referring toFIG. 4, an embodiment of an actuator54and a valve44is illustrated. In this example, valve44comprises a piston70having a head portion72and a valve portion74. Valve portion74is positioned to block flow of actuating fluid, e.g. hydraulic fluid, between a hydrostatic flow port76and control line adapter48when valve44is in a closed position, as illustrated inFIG. 4. Hydrostatic flow port76serves as an inlet port for actuating fluid flowing to the corresponding well tool38when valve44is in an open position. Piston head portion72is slidably mounted within a cavity78of the surrounding valve housing80, and a seal is created between head portion72and the wall forming cavity78by, for example, a seal member81. A biasing mechanism82is used to bias piston head portion72towards the end of cavity78closest to inlet port76. In the embodiment illustrated, biasing mechanism82comprises a fluid84, such as an oil, that prevents piston70from moving and opening valve44, until desired. A vent passage86extends through a valve body portion88and into fluid communication with cavity78. When valve44is held in a closed position, the escape of fluid84through vent passage86is prevented by a plug90, such as a viton plug.

The illustrated biasing mechanism is one example of a mechanism to hold piston70and thus valve44in a closed position. However, other biasing mechanisms, such as compressed gas, springs or other mechanisms able to releasably store energy, can be used to enable movement of piston70. Also, mechanisms other than plug90can be used to prevent the escape of fluid84through vent passage86, such mechanisms including a plug which is spring loaded or an o-ring arrangement combined with a pin that is pulled from the inside diameter of the passage.

In the embodiment ofFIG. 4, plug90is held in place by actuator54until actuated. As illustrated, a lead screw92is positioned to hold plug90such that it blocks the escape of fluid from cavity78. Lead screw92is coupled to a motor and gearbox unit94by an appropriate coupling96. Motor and gearbox unit94comprises a motor98drivingly coupled to a gearbox100.

When the specific pressure pulse signal is received by pressure sensor56and decoded by electronics system58, the electronics system58then starts motor98which turns gearbox100. Gearbox100is coupled to lead screw92which retracts upon rotation. Piston70maintains fluid84under pressure and, as lead screw92retracts, plug90moves under the pressure of fluid84acting against plug90in vent passage86, as illustrated inFIG. 5. When the lead screw92is fully retracted, plug90is forced free of vent passage86, as illustrated best inFIG. 6. Once plug90is free of vent passage86, fluid84is continually forced through vent passage86by the pressure of the actuating fluid entering inlet port76and acting against the opposite side of piston head portion72. As the piston70is forced along cavity78, as further illustrated inFIG. 7, fluid84is continually metered through vent passage86and into, for example, an atmospheric chamber disposed on a side of valve body portion88opposite from cavity78. The atmospheric chamber may be contained, for example, within the cylindrical body or other housing containing electronic system58. Or, the housing containing the electronic system58can itself be used as the atmospheric chamber for venting of the fluid.

Referring generally toFIG. 8, when piston head portion72is forced all the way through cavity78, valve portion74no longer blocks hydrostatic flow port76, and valve44is in the open position. Once this occurs, actuating fluid, e.g. hydraulic actuating fluid, flows through hydrostatic flow port76, as illustrated by arrows102, and into inlet port50of well tool38. In this example, hydrostatic pressure is applied through inlet port50to well tool38to actuate the tool. However, in an alternate embodiment, gas pressure can be used to actuate well tool38. In completions with multiple tools38, each of the tools can be activated at separate, specific, desired times by applying the specific pressure pulse signal associated with the corresponding electronic trigger system.

Depending on the configuration of electronic trigger systems42, the systems can be mounted in a variety of locations and to a variety of components of completion22. In the embodiments illustrated, each electronic trigger system42is formed as elongate body64, e.g. a long cylindrical body. With this design, each trigger system42can be deployed at least partially within a recess104formed, for example, along an outer surface106of the completion component108, as illustrated inFIG. 9. In the one embodiment, the completion component108is a carrier tubing designed for coupling in axial alignment with other components of completion22. The electronic trigger system42may be attached to the completion component108, e.g. within recess104, by an appropriate bracket110, such as a strap. In other embodiments, the electronic trigger system may be strapped onto the outside of the tubing joint or a hydraulic tool. Also, the trigger system may be incorporated into the wall of the tubing joint or well tool, or the trigger system may be deployed on the inside of the tubing joint or well tool.

In these embodiments, valve44and actuator54require only low-power for operation, which means the battery or batteries62can be made relatively small. This enables creation of an electronic trigger system with a form factor, e.g. the elongate form factor described above, that is relatively easy to incorporate in a variety of completion systems for use with many types of hydraulic completion tools. Each electronic trigger system42can be incorporated directly into the hydraulic tool to be actuated, or it can be deployed at a separate location along the completion and coupled via control line46to the tool with which it is associated.

Accordingly, although only a few embodiments of the present invention 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 invention. Accordingly, such modifications are intended to be included within the scope of this invention as defined in the claims.