Embodiments of the subject matter disclosed herein generally relate to downhole operations associated with an oil and gas well, and more specifically, to devices and methods for connecting and releasing a downhole tool or portions of a tool string within the wellbore.
Wells for the extraction of hydrocarbons, typically oil and gas, require the use of various tools to perform the downhole operations within the wellbore which may include drilling, completion and production related activities. Tools, typically as a string of tools, need to be lowered into the well in a controlled manner by a conveyance method which may include wireline, slickline, and tubing based methods. Such tool strings may include drills, measurement and sampling devices, perforating guns, packers, plugs, valves, setting tools, various types of tubing and other tools run-in individually or in serial connection with one or more other tools.
Modern wellbores may be drilled vertically as well as horizontally and often have sections that undulate or deviate from planned trajectory. Since these deviations may occur within a relatively short distance; tight bends can occur within the casing. As a result, a tool or portions of a string of tools may become lodged within the casing and need to be released from the wireline in order to be later retrieved or drilled out through a separate operation.
Traditionally, as illustrated in
The other end of wireline 110 is lowered into the well 112 and is attached to a tool or a string of tools 118. Tool(s) 118 may, for example, be one or a string of perforating guns, a sub, a toe-valve or other type of valve, a plug, a setting tool, or any combination of these or other downhole tools. Between wireline 110 and tool or tool string 118, a release tool 114 and stinger assembly 116 may be located to affect the release of tool 118 in the event the tool or string becomes lodged within the wellbore 112.
Release tools currently in use to provide disengagement of a tool from the conveyance vary principally in their source of power to affect the release and include electronic and motor driven devices, as well as explosively activated and complex pressure driven approaches. Such devices suffer from a high degree of complexity, lack of reliability and do not provide confirmation that disengagement downhole has occurred. Thus, there is a need for a new release tool that provides for disengagement utilizing simplified mechanisms, without use of explosives, and has higher reliability and the ability to measure and convey information as to the state of the tool string, as well as wellbore conditions.
According to an embodiment, there is a release tool for connecting and releasing one or more downhole tools of a tool string located within a wellbore. The release tool includes a housing having an axial bore and an upper section and a lower section connected by a main sub, an electronics assembly within the housing and configured to communicate with the surface of the wellbore, an activation mechanism within the main sub and configured to receive an electrical current from the electronics assembly, a valve assembly within the main sub and in operative communication with the activation mechanism and has a first piston to open a passageway to wellbore fluid, a second piston within the lower section of the housing held in an initial downward state by a spring, plural retainer dogs within the axial bore of lower section of the housing having an engagement recess disposed on an inner radial surface for clamping a portion of a tool string. The second piston includes a cavity that retains the plural retainer dogs in a clamped state until the second piston is acted upon by the wellbore fluid.
According to another embodiment, there is a release tool for connecting and releasing one or more downhole tools of a tool string located within a wellbore. The release tool includes a housing with an axial bore, a burst disk configured to open a passageway to wellbore fluid upon breakage at a predetermined pressure, a piston within the housing held in an initial downward state by a spring, and plural retainer dogs with an engagement recess for clamping a portion of a tool string. The piston includes a cavity to retain the plural retainer dogs in a clamped state until the piston is acted upon by wellbore fluid.
According to still another embodiment, there is a wireline release tool and measurement system. The system includes a wireline for lowering a tool string into a wellbore, a housing attached to the wireline with an axial bore and an upper section and a lower section connected by a main sub, an electronics assembly within the upper section of the housing to communicate with the surface of the wellbore via the wireline, a release assembly with plural retainer dogs within the axial bore of the lower section of the housing with an engagement recess on an inner radial surface for clamping and releasing a portion of a tool string. The release tool and measurement system also includes a measurement sensor within the main sub and to measure a parameter and communicate a measured value to the electronics assembly.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings:
The following description of the embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to a wireline tool disposed inside of a well. However, the embodiments discussed herein are not limited to a wireline in a well, but they may be applied to other conveyances and tools that are introduced into an enclosure which may call for a disengagement.
Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
According to an embodiment, a pressure actuated release tool is attached to a wireline and lowered downhole with a tool string. The release tool's electronics module receives a command from a surface communications panel to initiate disengagement and a fusible or degradable link causes a valve piston to shift which opens a passageway for the inflow of pressurized wellbore fluid into a chamber. The pressurized wellbore fluid acts upon a second spring-loaded piston which shifts position within a housing to cause a set of retainer dogs clamped to a downhole tool to open. The opening of the retainer dogs then allows for disengagement of a tool or a portion of tool string that is to be released.
For purposes of this disclosure, terms such as “upper”, “upward” or “uphole” and conversely “lower”, “downward” or “downhole” are used herein to refer to the position of a particular tool, or the position of a particular feature within a tool, in relation to its position within the wellbore. Thus terms “upper, “upward” or “uphole” refer to a position above another tool or feature in a vertical section of a well or a position generally closer to the surface of a well having vertical and horizontal sections. Similarly, “lower”, “downward” or “downhole” is a position closer the end or the toe of the well. In the accompanying figures, “upper”, “upward” or “uphole” will generally be depicted as to the left in a figure unless indicated otherwise.
According to an embodiment as shown in
Upper housing section 203 is mechanically connected to main sub 208. Main sub 208 houses activation mechanism 206 and valve assembly 209 including a first piston 237 (these aspects will be discussed and shown in greater detail below). Main sub 208 also includes an internal channel that provides for a fluid passageway 205 upon activation and opening of the valve assembly 209. Main sub 208 mechanically connects to lower housing section 218. Between upper 203 and lower 218 housing sections, port 210 provides fluid communication between the release tool 200 exterior and valve assembly 209.
The lower end of main sub 208 may further include an integrally machined section or a separately attached body that forms an extension 216 on the downward end of main sub 208 that is of smaller diameter than the I.D. of lower housing 218. Extension 216 acts as a fixed base for spring 212 and as a body upon which a locking collar piston 213 may slidably translate up and down. For simplicity, locking collar piston 213 hereafter will be referred to as “second piston”. Second piston 213 may be shaped on the downward end to include a cavity 217 sized to accept at least an upper portion of one or more retainer dogs 219. While the term “retainer dog” or “retainer dogs” may be used herein; these sections may be alternatively referred to as segments, locking segments, clamping segments, collet fingers, sections or segments, or multiple dogs may be referred to collectively as a singular collet.
In certain embodiments, three to eight retainer dogs 219 may be employed with each located fully within the axial bore 239 of the lower section 218 of the housing. In a preferred embodiment, each retainer dog 219 is typically comprised of a finger-like body 233 the base (upper) end of which is held in cavity 217 of second piston 213 thus holding the retainer dog in a fixed position corresponding to a closed or clamped state without the use of shear screws, lock rings or other frangible connection. The distal (lower) end of retainer dog 219 may include an engagement recess 223 disposed on an inner radial surface of finger 233 suitable to radially engage and lock onto the uphole neck 238 of a stinger assembly 221. Note that a stinger assembly may also be referred to as a “fishing neck” and serves as a releasable point and provides for mechanical connection to one or more tools lower in the string. Downhole from stinger assembly 221 may include an adaptor 224 or locking sub 222 and other tools necessary to make connection to a subsequent tool or tools lower in the string.
Turning to
Activation mechanism 206 may comprise a fuse or fusible link 304, and a resistive element 314 surrounding separable elements 303 enclosed within retainer head 301. For example, the fusible link 304 may be adjacent to or around or looped through the resistive element which maintains the resistive element in a wound state. Resistive element 314 may be provided as a torsional spring which in a compressed state holds center pin 308 in a restrained position. Once resistive element 314 breaks as a result of the heat applied; it frees separable elements 303 holding center pin 308 thus allowing it to move upward (uphole).
Valve assembly 209 comprises an internal piston 237 (hereinafter “first piston”) mechanically coupled with center pin 308 with first piston 237 housed within valve assembly body 306. Center pin 308 thus provides a mechanical linkage between the activation mechanism 206 principally housed within the retainer head 301 and first piston 237 of valve assembly 209. Retainer head 301 and valve assembly body 306 may be joined at a mating plate 302. First piston 237 is sealed via one or more O-rings 311 or other type seal within orifice 310 of valve assembly body 306 and thus may slidably translate therein. In preferred embodiments, once center pin 308 is freed by disengagement of separable elements 303, the center pin 308 and first piston 237 become movable under the force of wellbore pressure acting through port 210. In other embodiments, a secondary spring in a compressed state could be located at the base of first piston 237.
Recall from above, that main sub 208 mechanically connects upper 203 and lower 218 housing sections, and that port 210 located between the two sections provides fluid communication between the release tool 200 exterior and valve assembly 209. As illustrated in
In certain embodiments as shown in
Valve assembly 209 may also include a switch mechanism capable of providing feedback to the surface as to the state of the valve. This provides valuable confirmation to the surface as to the current state of release tool 200. In certain embodiments, referring back to
Returning to
Pressurization of atmospheric chamber 430 pushes second piston 213 uphole thus compressing spring 212. Therefore in this embodiment, since passageway 205 extends through main sub 208 to below second piston 213; piston 213 moves towards the port 210 rather than away from the port. In this regard, piston 213's movement is opposite the direction of the inflow of fluid. This approach advantageously provides for piston 213 to act as both a retention and a release device for the retainer dogs 219 whereby piston 213 is shifted and retainer dogs 219 are released as a result of pressurization of a single atmospheric chamber 430 located below the second piston 213. Further, the presently disclosed release assembly comprising the second piston 213 with cavity 217 that both retains and releases retainer dogs 219 from an uphole neck 238 of downward tool does not require the use of shear screws, breakable lock ring or other frangible connection.
With second piston 213 shifted uphole, retainer dogs 219 are freed from cavity 217 and engagement recess 223 disengages from the uphole neck 238 of the stinger assembly 221, i.e. the “fishing neck” is released and release tool 200 is now separated from the stuck downward tool or tools and can be withdrawn from the wellbore.
In other embodiments, electronics assembly 204 may also include an electronic circuit 240 comprising a timer 241 (
An exemplary method for operation of an exemplary release tool comprises the following stages: a signal from the surface controller is provided downhole via a wireline 110 to electronics assembly 204; electronics assembly 204 sends an electrical current to fuse link 304 of activation mechanism 206; fusible link 304 heats restriction element 314 which breaks and frees separable elements 303; separable elements 303 disengage center pin 308 which moves uphole; first piston 237 of valve assembly 209 shifts uphole opening a pathway through opening 210; pressurized wellbore fluid flows into passageway 205 of main sub 208, second piston 213 compresses spring 212 and frees retainer dogs 219 from cavity 217; and consequently retainer dogs 219 disengage from fishing neck 238 of stinger assembly 221.
In yet other embodiments, as shown for example in
Embodiments of the release tool 200 may also include a current feed-through current path designed around a pass-through switch as described in pending co-assigned U.S. patent application Ser. No. 16/194,580, which is incorporated herein by reference for all purposes. The current feed-through comprises a pass-through switch located inside the electrical assembly housing 204 and electrically connected between an electrical input and an electrical output; and a circuit limiter device located inside the same housing and electrically connected between the electrical input and the electrical output. The pass-through switch is connected in parallel to the circuit limiter device, between the electrical input and the electrical output for testing a downhole tool without closing a pass-through switch in the release tool.
In yet other embodiments, main sub 208 of release tool 200 may house additional components in the form of a variety of sensors. Such a system thus provides for downhole tool release as well as the capability to measure various wellbore parameters and parameters related to the tool string.
Also shown in
Also shown in
To compensate for this pressure-driven compression, another pressure compensating chamber 701 may be disposed within a section of wall of secondary sub 680. Chamber 701 provides two different diameter sealing surfaces 702 and 703 that are exposed to wellbore pressure versus atmospheric pressure on the other sides of the surfaces 704 and 705 inside the secondary sub 680. The difference between the areas is equivalent to the area of the 1⅝″ ACME connection in this example. The larger diameter of sealing surface 703 is on the downhole end, past tension transducer 630, thus providing a pulling force on the transducer. This results in the reduction of the net force on the tension transducer 630 due to well pressure acting on the piston areas and ideally fully compensates for the compressive effects such that the net force approaches zero. This enables an improved accuracy in the tool tension measurement.
The disclosed embodiments provide a downhole release tool for disengagement of a tool or portions of a tool string within a wellbore. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details. For example, where the phrase “mechanically connected” may be used therein, those skilled in the art of downhole tool design will readily contemplate that such connections may be provided by threads, including box by pin connections, lock rings, quick connects, collared connections, welding or other methods of joining mechanical components.
Although the features and elements of the present embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein.
This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims.
This application claims benefit and priority from U.S. Provisional Patent Application No. 62/870,421 filed on Jul. 3, 2019 and U.S. Provisional Patent Application No. 62/902,534 filed on Sep. 19, 2019, the content of both of which is incorporated in their entirety herein by reference.
Number | Date | Country | |
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62902534 | Sep 2019 | US | |
62870421 | Jul 2019 | US |
Number | Date | Country | |
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Parent | 16918309 | Jul 2020 | US |
Child | 18504504 | US |