Isolation valves

A valve assembly that can be deployed in a subterranean well that includes a valve adapted to selectively isolate a region of the subterranean well, and a separating apparatus. The separating apparatus may further include at least one member being formed from a functional material and at least two sleeves connected by the at least one member.

BACKGROUND OF THE DISCLOSURE

The invention generally relates to systems and techniques to actuate isolation valves, such as formation isolation valves, for example.

A formation isolation valve may be used in a well for such purposes as preventing fluid loss and controlling an underbalanced condition. The valve forms a controllable sealed access to formations below the valve. When the valve is open, well equipment (a tubular string, a wireline system, a slickline system, etc.) may be deployed through the valve for purposes of performing one or more testing, perforating and/or completion functions below the valve. After these functions are complete, the well equipment may be retrieved, and the valve may be subsequently closed.

For purposes of opening and closing the valve, an intervention may be performed. In the intervention, a tool, such as a shifting tool, is run downhole into the well to engage and change the state of the valve. More specifically, the shifting tool interacts with a mechanical section of the valve. The mechanical section typically is tied to a barrier valve element (a ball valve element, for example) of the valve so that linear motion of the shifting tool (caused by controlled movement of a string connected to the shifting tool, for example) acts to either directly or indirectly open or close the valve element. In addition, the mechanical section holds the valve element in position (i.e., keeps the valve either open or closed) after the shifting tool is removed from the valve. After the formation isolation valve is closed, the well may be suspended for days or months.

A well intervention typically consumes a significant amount of time and money. Therefore, interventionless techniques have been developed to operate the formation isolation valve. For example, a conventional formation isolation valve may include a chamber that has precharged nitrogen, which acts as a gas spring for purposes of providing downhole power to operate the valve. More specifically, a control mechanism (a J-slot-based mechanism, for example) of the valve, which limits expansion of the nitrogen, may also be used that controls opening and closing of the valve by manipulating the well pressure. After a given sequence of well pressure fluctuations, the control mechanism allows the nitrogen to expand to push a piston for purposes of rotating a ball valve element of the valve open.

A potential challenge in using the above-described formation isolation valve with precharged nitrogen is that the gas chamber of the valve typically is charged on the rig floor next to rig personnel before the valve is run downhole and installed. In addition, under certain well conditions, the well pressure may exceed the rating of the tools in the well or the rating of the ball valve element during the sequence of pressure fluctuations.

Thus, there exists a continuing need for better ways to remotely actuate a downhole tool, such as a formation isolation valve, for example.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify indispensable features of the claimed subject matter, nor is it intended for use as an aid in limiting the scope of the claimed subject matter.

The present disclosure introduces a valve assembly usable in a subterranean well, comprising: a valve adapted to selectively isolate a region of the subterranean well; and a separating apparatus comprised of: at least one member being formed from a functional material and at least two sleeves connected by the at least one member.

The present disclosure further introduces a method including sending an electrical signal to a separator apparatus comprised of a heating device member and at least one member comprised of a functional material, the at least one heating device member connected to the at least one member comprised of the functional material. The method also includes converting the electrical signal into thermal energy using the heating device member such that the at least one member separates into a plurality of pieces, and separating a first sleeve from a second sleeve such that a mandrel connected to the second sleeve is released. The method also includes transitioning a valve from a first state to a second state within a subterranean formation.

These and additional aspects of the present disclosure are set forth in the description that follows, and/or may be learned by a person having ordinary skill in the art by reading the material herein and/or practicing the principles described herein. At least some aspects of the present disclosure may be achieved via means recited in the attached claims.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to provide an understanding of the present disclosure. However, it may be understood by those skilled in the art that the methods of the present disclosure may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. At the outset, it should be noted that in the development of any such actual embodiment, numerous implementation-specific decisions may be made to achieve the developer's specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. In the summary and this detailed description, each numerical value should be read once as modified by the term “about” (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the summary and this detailed description, it should be understood that a range listed or described as being useful, suitable, or the like, is intended to include support for any conceivable sub-range within the range at least because every point within the range, including the end points, is to be considered as having been stated. For example, “a range of from 1 to 10” is to be read as indicating each possible number along the continuum between about 1 and about 10. Furthermore, one or more of the data points in the present examples may be combined together, or may be combined with one of the data points in the specification to create a range, and thus include each possible value or number within this range. Thus, (1) even if numerous specific data points within the range are explicitly identified, (2) even if reference is made to a few specific data points within the range, or (3) even when no data points within the range are explicitly identified, it is to be understood (i) that the inventors appreciate and understand that any conceivable data point within the range is to be considered to have been specified, and (ii) that the inventors possessed knowledge of the entire range, each conceivable sub-range within the range, and each conceivable point within the range. Furthermore, the subject matter of this application illustratively disclosed herein suitably may be practiced in the absence of any element(s) that are not specifically disclosed herein.

Referring toFIG.1, an embodiment of a formation isolation valve assembly100in accordance with the present disclosure controls access to a region of a well below the valve assembly100. In this manner, the valve assembly100allows a string, such as a string101, to pass through the valve assembly100to the region beneath the valve assembly100when the valve assembly100is in an open state (as depicted inFIG.1), and when the valve assembly100is in a closed state, the valve assembly100seals off communication with the region beneath the valve assembly100. An annular region, or annulus102, that is located between an exterior surface of the valve assembly100and a production tubing103of the well may be sealed off by a packer (not shown).

More specifically, in some embodiments of the present disclosure, the valve assembly100includes a ball valve104that assumes an open state for the string101to pass through the valve assembly100and assumes a closed state to seal off the region below the valve assembly100when the string101no longer extends through the ball valve104.

In some embodiments, when the formation isolation valve assembly100is first set in place downhole, the ball valve104may be opened (or run into the well bore open) to permit the string101to pass through. Alternatively, the formation isolation valve assembly100may be run with the string101already included through the ball valve104. The string101may include a gravel packing tool to perform gravel packing operations downhole. After the gravel packing operations are complete, the string101may be withdrawn from the well bore.

After the gravel packing operation is complete, the ball valve104is closed. In this manner, the string101may include a shifting tool105(near a lower end of the string101) to physically close the ball valve104. More specifically, after lower end of the string101is retracted above the ball valve104, a profiled section106of the shifting tool105engages (as described below) the valve assembly100and is operated in a manner (described below) to cause the ball valve104to close.

The valve assembly100also includes an operator mandrel107that moves up in response to applied tubing pressure (in the central passageway of the assembly100) and moves down when trigger mechanism (described below) is released. The downward travel of the operator mandrel107causes the mandrel107to contact a collet actuator108that is engaged with a ball valve operator mandrel109that, in turn, operates the ball valve104. In this manner, the downward movement of the operator mandrel107causes the ball valve operator mandrel109to move in a downward direction to open the ball valve104.

In other embodiments, to close the ball valve104via the shifting tool105, the profiled section106of the shifting tool105engages (as described below) the collet actuator108to force the collet actuator108up and down. On each upward stroke, the collet actuator108disengages from the ball valve operator mandrel109, as described below.

When the ball valve operator mandrel109moves up by a predetermined distance, the mandrel109closes the ball valve104. After the cycles occur, the ball valve operator mandrel109engages with the collet actuator108on the downstoke and remains engaged with the collet actuator108on the upstroke of the collet actuator108, thereby permitting the shifting tool105to lift the ball valve operator mandrel109up for a sufficient distance to close the ball valve104. The shifting tool105has nothing to do with the cycling mechanism of the ball valve104. The shifting tool105is used when the cycling mechanism fails or in formation isolation valves with no cycling mechanism. The cycling mechanism on the other hand is used to open the ball valve104remotely without intervention (by using any tool). Both are independent of each other. The ball valve104can be opened or closed independently by the shifting tool105. The shifting tool105has the necessary profiles to shift the ball valve operator mandrel109downhole to open the ball valve104and shift the ball valve operator mandrel109uphole to close the ball valve104.

Referring to the formation isolation valve assembly100in more detail,FIGS.2, and3depict sections100A and100B that form a section (of the valve assembly100) that houses the release module200and the mandrel107. The upper part of this section is formed from an upper housing section201that mates with a lower housing section202. In this manner, the lower end of the upper housing section201is received into a bore in the upper end of the housing section202. Both housing sections201and202are generally cylindrical and circumscribe a longitudinal axis of the valve assembly100.

In other embodiments and illustrated inFIG.2., the upper housing201contains the release module200. The release module200is an example of a type of separating apparatus, which may contain of one or more fracturing bolts205arranged longitudinally to circumscribe a vertical axis of the valve assembly100. The fracturing bolt205is a type of coupling mechanism (e.g., pins, screw or rods) that is (1) configured to couple at least two objects together and (2) at a predetermined point in time, can be configured to separate or fracture. As used herein the terms “separate” or “fracture” are defined to be the loss of a connecting mechanism such that after release, the object is in at least two separate pieces. In this case, the fracturing bolt205couples at least two cages (actuator cage208and release cage209) together, which provide additional support, stability and security for the fracturing bolts205. The fracturing bolt205is contained/secured in at least a portion of the actuator cage208and release cage209such that at least a portion of the fracturing bolt205is located on the surface of the actuator cage208and the release cage209. The actuator cage208contacts the upper support sleeve206and the release cage209contacts the lower support sleeve207, the upper support sleeve206and the lower support sleeve207both being arranged about a longitudinal axis of the valve assembly100. The fracturing bolt205may be comprised of a threaded or unthreaded cylindrical shaft having an optional head member attached to the cylindrical shaft. Regardless of the head/shaft arrangement, the shaft is comprised of a shaped memory alloy.

The fracturing bolt205is considered to be pre-strained or pre-loaded to a predetermined strain value. In other words, the fracturing bolt205is pre-strained when its structure has been deformed using an applied force. For example, the fracturing bolt205may be pre-strained by applying a sufficient force to both ends of the bolt causing the deformation (i.e., shrinking) of the fracturing bolt205. The fracturing bolt205may be comprised of a functional material such as a shape memory material in the martensitic phase at ambient and operating temperatures. Other examples of functional materials include piezoelectric materials, magnetostriction materials, electrorheological fluids and shaped memory plastics.

Upon receiving an electrical signal from the one or more wires203, the heating connector204converts the received electrical signal to a heat source (joule heating) causing a phase change to a high temperature austenitic phase such that fracturing bolt205fractures (i.e., separates into at least two pieces and/or experiences a reduction in length). This results in a crystal structure change in the grains of the bolt material, causing the fracturing bolt205to shorten in length. Since the fracturing bolt205is secured at both the ends to the actuator cage208and the release cage209respectively, it results in its fracture, thereby releasing the operator mandrel107and opening the ball valve104. According to one or more embodiments of the present disclosure, the electrical signal can be sent to the release module200through a control line or wire203running from surface to the isolation valve downhole that is directly connected to the release module200, to enable fracturing of the fracturing bolt205at the desired time. In alternative embodiments, a battery pack (not shown) can also be built into the smart release module200that can be activated remotely through a radiofrequency signal from the surface to provide the necessary electrical voltage required for fracturing the bolt.

As discussed above, the operator mandrel107moves up in response to applied tubing pressure in a central passageway210of the valve assembly100. However, the fracturing of the fracturing bolt205separates the connection between the upper support sleeve206and the lower support sleeve207causing the operator mandrel107to move down in response to the pressure exerted by a gas chamber301(FIG.3). The gas chamber301, in some embodiments, is formed from an annularly recessed cavity located between the upper housing section201and the operator mandrel107. The gas chamber301, in other embodiments of the invention, may include either atmospheric pressure or compressed nitrogen gas. However, in other embodiments, the gas chamber301may be replaced by a compression spring or another type of spring, which would enable mechanical engagement with the downhole sections discussed above to open the ball valve104of the valve assembly100.

The responsiveness of the operator mandrel107to the tubing pressure and the pressure that is exerted by the gas in the chamber301is attributable to an upper annular surface302of the mandrel107that is in contact with the gas in the gas chamber301and a lower annular surface303of the ball valve operator mandrel109that is in contact with the fluid in the central passageway210. Therefore, when the fluid in the central passageway210exerts a force (on the lower annular surface303) that is sufficient to overcome the force that the gas in the chamber301exerts on the upper annular surface302, a net upward force is established on the mandrel107. Otherwise, a net downward force is exerted on the mandrel107(i.e., piston effect) to force the ball valve operator mandrel109down. In other words, the potential energy stored in the chamber301in the form of compressed nitrogen gas or spring pushes the ball valve operator mandrel109downhole like a piston. This causes the ball valve operator mandrel109to engage and push a latch nut and other connected mandrels (not shown) in the mechanical section of the valve assembly.

Referring toFIG.3, the mandrel107includes an exterior annular notch to hold O-rings304to seal off the bottom of the gas chamber301. O-rings305are also located in an interior annular notch of the upper housing section201(seeFIG.3) to form a seal between the upper housing201and the operator mandrel107to seal off the gas chamber301. O-rings306form a seal between the upper housing sections201and the lower housing section202.

In view of the entirety of the present disclosure, including the figures and the claims, a person having ordinary skill in the art will readily recognize that the present disclosure introduces a valve assembly usable in a subterranean well, comprising: a valve adapted to selectively isolate a region of the subterranean well; and a separating apparatus comprised of: at least one member being formed from a functional material and at least two sleeves connected by the at least one member.

For example, the separating apparatus may further comprise a heating device member connected to the at least one member. The separating apparatus may further comprise an electrical wire connected to the heating device member such that when an electrical current is applied to the heating device member, the at least two sleeves are no longer connected by the at least one member. The separating apparatus may further comprise an actuator cage and a release cage, the actuator cage and the release cage being arranged longitudinally about a vertical axis of the valve assembly.

For example, the valve assembly may further comprise a mandrel to be operated by pressure to transition the valve from a first state to a second state. The first state is a closed state and the second state is an open state.

The valve assembly may also comprise a charge chamber located between a mandrel and a housing of the valve assembly, wherein the charge chamber contains atmospheric pressure, compressed nitrogen or a compression spring.

The functional material may be a material selected from the group consisting of shaped memory alloys, piezoelectric materials, magnetostriction materials, electrorheological fluids, shaped memory plastics and combinations thereof.

The present disclosure also introduces a method comprising: sending an electrical signal to a separator apparatus comprised of a heating device member and at least one member comprised of a functional material, the at least one heating device member connected to the at least one member comprised of the functional material; converting the electrical signal into thermal energy using the heating device member such that the at least one member separates into a plurality of pieces; separating a first sleeve from a second sleeve such that a mandrel connected to the second sleeve is released; and transitioning a valve from a first state to a second state within a subterranean formation.

For example, the mandrel may be operated by pressure to transition the valve from a first state to a second state such that the first state is a closed state and the second state is an open state.

The sending may further comprise sending an electrical signal via one or more wires connected to the separator apparatus, or sending a wireless electrical signal to the separator apparatus.

The valve may be a formation isolation valve. The separating apparatus may further comprise an actuator cage and a release cage, the actuator cage and the release cage being arranged longitudinally about a vertical axis of the valve assembly.

The foregoing outlines features of several embodiments so that a person having ordinary skill in the art may better understand the aspects of the present disclosure. A person having ordinary skill in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same functions and/or achieving the same benefits of the embodiments introduced herein. A person having ordinary skill in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.