Patent Application
20200248523
A back-pressure valve (BPV) is a type of check valve, typically installed in the tubing hanger, to isolate the production tubing. The back-pressure valve is designed to hold pressure from below to isolate well pressure, yet enable fluids to be pumped from above as required for well-control purposes, such as to kill the well. Thus, a BPV reduces downtime and operating cost by allowing for repairs without killing the well. The BPV is commonly used during the nipple down and up (removal and installation) of the drilling blow out preventer (BOP) stack, nipple up or down (installation and removal) of a Christmas tree, testing of the Christmas tree or BOP (with a different 2-way check valve), and during the replacement of the master valve. A common type of BPV is the Cameron Type H BPV. It is sometimes necessary to remove the Christmas tree or repair the lower master valve of the well. Thus the BPV can be reinstalled in the hanger without killing the well.
When the BOP is set, it must be tested against something. A different two-way check valve is used and replaces the BPV to check that the BOP seals in both directions. Sometimes there is pressure in the well from below, and the two-way check valve cannot be removed without a special tool called a lubricator. A lubricator is not typically kept on site, and often requires an inordinate amount of time to obtain. In addition, a lubricator is a complicated tool that requires an experienced operator to utilize.
Features and advantages of the invention will be apparent from the detailed description which follows, taken in conjunction with the accompanying drawings, which together illustrate, by way of example, features of the invention; and, wherein:
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.
Although the following detailed description contains many specifics for the purpose of illustration, a person of ordinary skill in the art will appreciate that many variations and alterations to the following details can be made and are considered to be included herein.
Accordingly, the following embodiments are set forth without any loss of generality to, and without imposing limitations upon, any claims set forth. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
In this disclosure, “comprises,” “comprising,” “containing” and “having” and the like can have the meaning ascribed to them in U.S. Patent law and can mean “includes,” “including,” and the like, and are generally interpreted to be open ended terms. The terms “consisting of” or “consists of” are closed terms, and include only the components, structures, steps, or the like specifically listed in conjunction with such terms, as well as that which is in accordance with U.S. Patent law. “Consisting essentially of” or “consists essentially of” have the meaning generally ascribed to them by U.S. Patent law. In particular, such terms are generally closed terms, with the exception of allowing inclusion of additional items, materials, components, steps, or elements, that do not materially affect the basic and novel characteristics or function of the item(s) used in connection therewith. For example, trace elements present in a composition, but not affecting the compositions nature or characteristics would be permissible if present under the “consisting essentially of” language, even though not expressly recited in a list of items following such terminology. When using an open ended term in the specification, like “comprising” or “including,” it is understood that direct support should be afforded also to “consisting essentially of” language as well as “consisting of” language as if stated explicitly and vice versa.
“The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Similarly, if a method is described herein as comprising a series of steps, the order of such steps as presented herein is not necessarily the only order in which such steps may be performed, and certain of the stated steps may possibly be omitted and/or certain other steps not described herein may possibly be added to the method.
The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.
As used herein, “enhanced,” “improved,” “performance-enhanced,” “upgraded,” and the like, when used in connection with the description of a device or process, refers to a characteristic of the device or process that provides measurably better form or function as compared to previously known devices or processes. This applies both to the form and function of individual components in a device or process, as well as to such devices or processes as a whole.
As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result.
As used herein, “adjacent” refers to the relative placement of one object with respect to another object. In some examples, objects that are described as being “adjacent” to one another may be in a side-by-side or other similar positional relationship that can include objects that are in direct contact with one another and objects that are in close proximity to one another. The exact degree of proximity may in some cases depend on the specific context.
As used herein, “coupled” refers to a relationship of connection or attachment between one item and another item, and includes relationships of either direct or indirect connection or attachment. Any number of items can be coupled, such as materials, components, structures, layers, devices, objects, etc.
As used herein, “directly coupled” refers to a relationship of physical connection or attachment between one item and another item, where the items have at least one point of direct physical contact.
As used herein, “indirectly coupled” refers to a relationship of connection or attachment between one item and another item where the items do not have a point of direct physical contact with one another. Rather, such items can be connected, attached, or joined together by an intermediate item. For example, when a first layer of material is bound or joined to a second layer of material using an intermediate layer in between the first and second layer, the first and second layers can be said to be indirectly coupled.
Unless otherwise specified, the terms “plug tool” and “plug” are used interchangeably herein.
Reference throughout this specification to “an example” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment. Thus, appearances of the phrases “in an example” in various places throughout this specification are not necessarily all referring to the same embodiment.
An initial overview of technology embodiments is provided below and then specific technology embodiments are described in further detail later. This initial summary is intended to aid readers in understanding the technology more quickly but is not intended to identify key features or essential features of the technology nor is it intended to limit the scope of the claimed subject matter.
A plug tool is presented to selectively plug a back pressure valve (BPV) in a tubing hanger associated with a wellhead of a well. In one aspect, the plug can be used with an existing BPV modified to better accommodate the plug tool, and provide a matching seal. In another aspect, the plug tool and the BPV can be provided together as a valve and plug tool. The plug tool, and the valve and plug tool, can seal bottom hole pressure from the well during removal of the Christmas tree, and can retain control of the well while the Christmas tree is removed. Thus, the plug tool, and the valve and plug tool, allow a blowout preventer (BOP) to nipple-up and be tested without removing the BPV and without replacing the BPV with a two-way check valve. Thus, the plug tool, and the valve and plug tool, allows the BOP to be tested from above. In addition, the plug tool can selectively plug the BPV without contacting a poppet in the BPV, and thus without modifying well control. In addition, the plug tool can be removed while the BPV is still installed. Thus, if there is well pressure from below, the BPV allows pumping of kill fluid through the BPV to normalize pressure, such as vacuum.
A wellhead consists of the pieces of equipment mounted at the opening of the well to regulate and monitor the extraction of hydrocarbons from the underground formation. The equipment also prevents leaking of oil or natural gas out of the well, and prevents blowouts due to high pressure formations. Formations that are under high pressure typically require wellheads that can withstand a great deal of upward pressure from the escaping gases and liquids. The wellhead can comprise three components, namely: the casing head, the tubing head, and the Christmas tree.
The Christmas tree provides well control and can be used in an emergency shut down system. The Christmas tree is positioned on the top of the wellhead casing system and provides an interface between the well and the production and process facility. The Christmas tree has an assembly of gate valves which control the flow of hydrocarbons. The Christmas tree can have individual valves bolted together, or it can have a cast or forged steel solid block in which valve chests are machined, or a combination of both. The valve seats and gates can be removable for replacements or repair. A typical Christmas tree can have a master gate valve, a pressure gauge, a wing valve, a swab valve, a choke, and a number of check valves.
The casing head is mounted to a casing hanger. Several valves and plugs will normally be fitted to give access to the casing to allow the casing to be opened, closed, and bled down, and sometimes to allow the flowing well to be produced through the casing as well as the tubing. The tubing hanger is used to position tubing in the well.
Referring to
The BPV 14 is removably disposable in the tubing hanger 18, as shown in
The BPV 14 and the valve body 26 also have a slot 54 in a top of the valve body 26 extending across the valve body 25 and the bore 34. The slot 54 can receive a cross pin of a tool, such as a running tool, for setting and removing the BPV 14 with respect to the tubing hanger 18. The BPV 14 and the valve body 26 also have internal screw threads 58 in the bore 34 and located between the poppet 38, and the stem 50 thereof, and the slot 54. Thus, the internal screw threads 58 are located above the poppet 38, and below the slot 54. The internal screw threads 58 can be right had screw threads. An annular, circumferential inner wall 62 is formed in the bore 34 that is parallel with a longitudinal axis 66. The inner wall 62 is positioned between the slot 54 and the internal screw threads 58. The inner wall 62 is flat with an axially flat surface without screw threads. Thus, the inner wall 62 can define a seal surface located above the internal screw threads 58 and below the slot 54, and also above the poppet 38. Thus, the seal surface can be utilized without interfering with the poppet 38, as described below. In addition, an annular step 70 is formed in the bore 34 perpendicularly to the longitudinal axis 66. The step 70 can be located between the inner wall 62 and the internal screw threads 58. The step 70 can define a stop for the plug tool 10 as described below.
For setting the BPV 14, a running tool is inserted into the right-hand thread 58 at the top of the BPV, and then attached to a rod. When the BPV has been lowered into the tubing hanger 18, the rod is lowered so that a cross pin in the running tool engages in the slot 54 on the top of the BPV. Left hand (anti-clockwise) rotation is applied to insert the BPV 14 into the tubing hanger 18. Once the BPV 14 is fully seated, the rod is moved up to lift the pin from the slot 54 and left-hand rotation backs out the running tool from the BPV. For removal of the BPV 14, a pulling tool is attached to the rod and lowered to the BPV. Right-hand (clockwise) rotation makes up the pulling tool. The rod is lowered into the slot 54 on the top of the PBV 14 and right-hand (clockwise) rotation removes the BPV from the tubing hanger 18.
The plug tool 10 can be removably coupled to the BPV 14 to selectively and completely plug the bore 34 of the BPV 14 and the valve body 26. The plug tool 10 has a plug body 74 with opposite upper and lower ends. In one aspect, the plug tool 10 and the plug body 74 can be formed of steel, and can be machined from rod stock. The plug tool 10 and the plug body 74 have lower screw threads 78 on the lower end of the plug body that match the internal screw threads 58 of the valve body 26 of the BPV 14. In one aspect, the lower screw threads 78 of the plug 10 are right-hand screw threads. Together, the lower screw threads 78 of the plug tool 10, and the inner screw threads 58 of the BPV 14, form a threaded connection 82 between the plug tool 10 and the BPV 14 that removably couples the plug tool 10 to the BPV 14, and the plug body 74 to the valve body 26.
The plug tool 10 also carries a seal 86 to seal between the plug body 74 and the seal surface 62 of the bore 34 of the BPV 14. Thus, the seal 86 is located above the threaded connection 82 when the plug tool 10 and the plug body 74 are coupled to the BPV 14 and the valve body 26, as shown in
In addition, the plug tool 10 has an annular flange 94 or shoulder circumscribing the plug body 74 and located above the lower screw threads 78 and below the seal 86. The annular flange 94 abuts to the annular step 70 in the bore 34 of the valve body 26 when the plug tool 10 and the plug body 74 are coupled to the BPV 14 and the valve body 26, as shown in
In addition, the plug tool 10 has upper screw threads 102 near the upper end of the plug body 74. The upper screw threads 102 can be different than the lower screw threads 78 of the plug tool 10, and different than the internal screw threads 58 of the BPV 14. Thus, the different screw threads 78 and 102 resist inadvertent installation of the plug tool 10 upside down. The upper screw threads 102 can also define retrieving threads to match internal screw threads of a retrieval tool 120, as discussed below. In one aspect, the upper screw threads 102 of the plug 10 can be left-hand screw threads, while the lower screw threads 78 are right hand screw threads. In another aspect, the upper and lower screw threads 102 and 78 of the plug tool 10 can have different profile shapes, as shown. For example, the lower screw threads 78 can have a saw tooth or triangular profile, while the upper screw threads 102 can have a more square profile. In another aspect, the upper and lower screw threads 102 and 78 of the plug tool 10 can have different diameters. For example, the upper screw threads 102 can have a greater diameter than the lower screw threads 78. Again, the different screw threads 78 and 102 resist mis-installment.
Furthermore, the plug tool 10 and the plug body 74 can have opposite flats 106 located intermediate the upper and lower screw threads 102 and 78. The flats 106 are also located to be exposed beyond the BPV 14 when the plug tool 10 is coupled to the BPV 14. The flats 106 can receive a tool, such as a wrench, to help tighten and loosen the plug tool 10 from the BPV 14, such as for testing, demonstration, or emergency purposes. The flats 106 can also be used in manufacture of the plug tool 10 and the plug body 74. The plug tool 10 and the plug body 74 can also have a bolt head 110 at a top of the plug body 74. The bolt head 110 can receive a tool, such as a wrench or socket, to help tighten and loosen the plug tool 10 from the BPV 14, such as for testing, demonstration, or emergency purposes.
Referring to
Referring to
Referring to
A method for servicing a wellhead with a tubing hanger 18, a Christmas tree and a blow out preventer (BOP) with the valve and plug tool 22 described above comprises:
In addition, the method can further comprise pumping kill fluid through the BPV 14 to kill the well and establish a vacuum when there is pressure from below; and pulling the BPV 14 without using a two-way valve or a lubricator or a plug that screws into a lift thread of the tubing hanger 18.
Some aspects of a BPV are shown in U.S. Pat. No. 4,825,945, which is hereby incorporated herein by reference.
It is to be understood that the examples set forth herein are not limited to the particular structures, process steps, or materials disclosed, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular examples only and is not intended to be limiting.
Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more examples. In the description, numerous specific details are provided, such as examples of lengths, widths, shapes, etc., to provide a thorough understanding of the technology being described. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
While the foregoing examples are illustrative of the principles of the invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts described herein. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.
Priority is claimed to U.S. Provisional Patent Application Ser. No. 62/918,494, filed Feb. 2, 2019, which is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62918494 | Feb 2019 | US |
