Wellbore chemical injection with an adaptor flange

Abstract

Devices and methods for wellbore chemical injection with an adaptor flange is provided. In one aspect, an adaptor flange includes a body. The body defines a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter. The body further includes a neck portion connecting the first portion to the second portion. An inner diameter transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to wellbore chemical injection and specifically to injection from a surface of the wellbore through a wellhead.BACKGROUND

[0002] Wellbore operations utilize well tools installed within a wellbore formed in a subterranean zone (e.g., a formation, a portion of a formation, multiple formations). Fluids (e.g., drilling mud) used during wellbore formation or hydrocarbons (e.g., petroleum, natural gas, combinations of them) produced through the wellbore after formation and completion can corrode the well tools. Chemicals, such as corrosion inhibitors, scale inhibitors, emulsion preventive inhibitors, asphaltene inhibitor, to name a few, can be injected from a surface of the wellbore into the wellbore (e.g., into a wellbore-tubing annulus) to minimize such corrosive effect of fluids that flow through the wellbore. The chemicals can be injected using a chemical injection system that is installed at the surface of the wellbore. The chemical injection system can be fluidically coupled to the wellhead, specifically to the wellhead to inject the chemicals through a tubing spool, which is a component of the wellhead.SUMMARY

[0003] The present disclosure describes methods, devices, systems and techniques for wellbore chemical injection adaptor flange system through tubing spool side outlet port.

[0004] The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIGS. 1A, 1B and 1C are examples of different arrangements to inject chemicals into a wellbore using an adaptor flange described in this disclosure.

[0006] FIG. 2 illustrates a schematic diagram of a wellbore chemical injection system disposed at a surface of a wellbore.

[0007] FIG. 3A illustrates a schematic diagram of a wellhead including a tubing spool to which an example implementation of a wellbore chemical injection system is connected.

[0008] FIG. 3B illustrates a schematic diagram of flowing chemicals through the adaptor flange of FIG. 3A.

[0009] FIG. 4A illustrates a cross-section view of an example adaptor flange.

[0010] FIG. 4B illustrates side views of two ends of the example adaptor flange.

[0011] FIG. 4C illustrates a schematic view of an example wellbore chemical injection assembly.

[0012] FIG. 4D illustrates a schematic view of an example adaptor flange with a VR plug.

[0013] FIG. 5 illustrates a schematic diagram of a tubing spool and the example wellbore chemical injection assembly of FIG. 4C.

[0014] FIG. 6 illustrates a schematic view of an implementation of the example adaptor flange between two gate valves.

[0015] FIG. 7 illustrates an example process to inject chemicals through the example adaptor flange.

[0016] It is to be understood that the various exemplary implementations shown in the figures are merely illustrative representations and are not necessarily drawn to scale.DETAILED DESCRIPTION

[0017] Hydrocarbons entrapped in subsurface reservoirs flow from the reservoirs through the subterranean zone into the wellbore formed in the subterranean zone. Wellbore equipment are installed within the wellbore to produce the hydrocarbons to the surface. The fluids, e.g., high saline formation brines, various mixtures of oil and mixtures of gas (such as natural gas, hydrogen sulfide, carbon dioxide) that flow into the wellbore through the subterranean zone are extremely corrosive. The wellbore equipment, e.g., tubulars, packers, and the like, can be adversely impacted by the long-term contact with such fluids. For example, the equipment can corrode, or scales or sludges can build up on the equipment or both. The adverse impact on the wellbore equipment, in turn, can impact well production, well integrity, surface production facilities and the like. The adverse impact of the wellbore fluids can be reduced by flowing (i.e., injecting or pumping) chemical inhibitors into the wellbore. The chemicals can be pumped from a surface of the wellbore continuously to downhole locations, specifically to the area of the designed target depth.

[0018] This disclosure describes This disclosure describes a wellbore chemical injection assembly with an adaptor flange that can be coupled to a tubing spool inlet of a wellhead of a wellbore formed in a subterranean zone. In some aspects, an adaptor flange includes a body. The body defines a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening. The body further includes a neck portion connecting the first portion to the second portion. An inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion.

[0019] Implementations of the present disclosure can provide one or more of the following technical advantages. For example, the techniques described here can improve efficiency and safety of wellbore chemical injection operations by deploying internal fail-safe systems. Particularly, the techniques described are mechanical solutions that can be deployed with lesser resource consumption compared to smart solutions that implement pneumatic, hydraulic or electrical actuators. The adaptor flange has two ends with unequal outer diameters. The larger end can be coupled to a larger gate valve. A larger gate valve can allow the installation of a larger VR plug or check valve, as during installation a portion of the VR plug or check valve may extend into the gate valve. Therefore, with a larger gate valve and the adaptor flange, two VR plugs or check valves can be installed at side ports of a wellhead. These two VR plugs or check valves can establish two barrier during the replacement of the gate valve. In some implementations, a check valve is installed in the adaptor flange, which prevents backflow or the reverse flow of formation fluids through the tubing spool gate valve. This ensures that formation-related gases and corrosive fluids are unable to reach the gate valve, thereby enhancing operational lifespan of the gate valve. Installing check valve type VR plug in the tubing spool or in the flange setup is much more safer application that installing check valves out of the wellhead. Moreover, the arrangement of the VR plug profile allows easy installation, removal or replacement of a VR plug or a threaded check valve. When the adaptor flange is deployed with a VR plug, the adaptor flange can serve as a barrier that facilitates replacing gate valves on the side outlet of the tubing spool. Depending on the well type and wellhead pressures, one or two barriers may be required during gate valve replacement. If only one barrier is needed, the VR plug can be utilized and installed directly into the outlet or inlet port VR profile of the wellhead. If two barriers are required, another VR plug may be installed into the adapter flange VR profile.

[0020] FIGS. 1A, 1B and IC are examples of different arrangements to inject chemicals into a wellbore 100 using the adaptor flange 102 described in this disclosure. The arrangements can be implemented to inject chemicals into a tubing annulus to transfer the chemicals to downhole locations within the wellbore 100. FIG. 1A shows a schematic arrangement of using the adaptor flange 102 to inject chemicals into a downhole location in the wellbore 100 for flow in an uphole direction through a production tubing104 to the surface. The wellbore 100 is formed in a subterranean zone 106. The wellbore 100 can be cased and cemented 108 or can be non-cement cased or partially cased. Perforations 110 formed in the wellbore wall allow hydrocarbons to flow from the subterranean zone 106 into the wellbore 100. Packers 112 can be installed near a downhole end of the production tubing 104 to isolate a region of the wellbore 100 below the packers 112 from a region above the packers 112. The hydrocarbons flow from the subterranean zone 106 in an uphole direction (arrows 114) towards a downhole inlet of the production tubing 104 and towards the surface of the wellbore 100.

[0021] At the surface, a wellhead assembly can be installed to deploy wellbore equipment (including the production tubing 104, the packers 112, etc.) within the wellbore 100, and also to serve as a connection point for surface equipment. The wellhead assembly can include a wellhead 116, which is a network of fluidic inlets, outlets and flow control equipment (such as valves) to which the adaptor flange 102 is fluidically coupled. In particular, the adaptor flange 102 can be fluidically coupled to an inlet formed in a tubing spool 118 of the wellhead 116. A control line 120 (e.g., a tubing or a pipe) extends from the tubing spool 118 to a downhole location that is downhole of the inlet to the production tubing 104. For example, the control line 120 can pass through an annulus formed by the production tubing 104 and the casing installed in or inner wall of the wellbore 100, and through the packers 112. Chemicals can be injected from the surface of the wellbore 100 through the control line 120 to the downhole location. The injected chemicals are flowed in an uphole direction (arrows 122) by the hydrocarbons and swept into the production tubing 104. As the chemicals flow towards the surface, the chemicals contact the wellbore equipment (such as the inner walls of the production tubing 104) to prevent, reduce or reverse the adverse effects mentioned earlier.

[0022] FIG. 1B shows another schematic arrangement of using the adaptor flange 102 to inject chemicals into a downhole location in the wellbore 100 for flow in an uphole direction through a production tubing 104 to the surface. The arrangement of FIG. 1B is substantially identical to that of FIG. 1A, except that the arrangement of FIG. 1B does not implement the packers 112 (FIG. 1A). The arrangement of FIG. 1B allows monitoring annulus pressure behind the production tubing 104, which helps to monitor liquid loading condition of the wellbore 100. FIG. 1C shows another schematic arrangement of using the adaptor flange 102 to inject chemicals into a downhole location in the wellbore 100 for flow in an uphole direction through a production tubing 104 to the surface. The arrangement of FIG. 1C is substantially identical to that of FIG. 1A, except that the arrangement of FIG. 1C does not implement the control line 120 and does not implement packers. Instead, the chemicals are injected from the surface, through the tubing spool 118, directly into the annulus. The chemicals will travel downhole through the annulus and enter the production tubing 104 with the hydrocarbons. The wellbore chemical injection adaptor flange 102 can be used to inject chemicals in any of the arrangements shown in FIGS. 1A-C or other arrangements in which wellbore equipment installed within a wellbore needs to be treated with chemicals injected from the surface.

[0023] FIG. 2 shows a schematic diagram of a wellbore chemical injection system 200 disposed at a surface of the wellbore 100. The system 200 is shown as being implemented with the wellbore 100 described with reference to FIG. 1C. However, the system 200 is useable with any of the arrangements shown in FIGS. 1A, 1B and IC or other arrangements in which wellbore equipment need chemical treatment. The system 200 includes a chemical reservoir 202 (e.g., a tank) that stores the chemical or chemicals to be injected into the wellbore 100. A chemical line 204 (e.g., tubing or pipe) fluidically couples the reservoir 202 to the adaptor flange 102. Flow through the chemical line 204 is implemented using a pump 206 (e.g., a high pressure pump) and flow control equipment (e.g., control valves 208a, 208b) fluidically coupled along the length of the chemical line 204. One or more of the control valves (e.g., control valves 208b) can be installed near and fluidically coupled to the wellbore chemical injection adaptor flange 102. The adaptor flange 102 is fluidically coupled to an inlet of the tubing spool 118 of the wellhead 116.

[0024] The adaptor flange 102 and the tubing spool inlet can be coupled using valve removal (VR) plug profiles. The VR plug profiles can be an American Petroleum Institute (API) Sharp Vee VR profile (called “Sharp Vee”) profile that is rated for pressures between 3,000 pounds per square inch (psi) (2.1e7 Pascal) and 10,000 psi (6.9e7 Pascal). Tubing spools have API standard VR plug profiles. VR plugs do not stay in installed positions in the side outlet ports at all times. In some situations, the VR plugs can be installed and kept in the wellhead. If the standard VR plug is installed, they fully isolate the side outlet port.

[0025] FIG. 3A is a schematic diagram of a wellhead 116 including a tubing spool 118 to which an example implementation of a wellbore chemical injection system is connected. The wellhead 116 can be attached to different types of tubings installed within the wellbore, e.g., a surface casing 302, an intermediate casing 304, the production tubing 104. The wellhead 116 can include multiple spools including a top tubing spool 118, a first casing spool 306 and a second casing spool 308. Each spool can be fluidically coupled to one of the tubings or casing installed within the wellbore 100. The top tubing spool 118 can be fluidically coupled to the production tubing 104. Each spool can be fluidically coupled to respective gate valves, e.g., gate valves 310a, 310b, 310c, 310d fluidically coupled to the top tubing spool 118, gate valves 312a, 312b fluidically coupled to the first casing spool 306, gate valves 312c, 312d fluidically coupled to the second casing spool 308. The gate valves coupled to the spools can include outlets that can couple to flow equipment (such as tubings) using which fluid flow into or out of the respective spools can be controlled. A production tree 314 is installed above the top tubing spool 118 and can be fluidically coupled to the top tubing spool 118 through a gate valve 316.

[0026] In some implementations, the adaptor flange 102 can be fluidically coupled to the top tubing spool 118 between the gate valve 310c and an inlet to the tubing spool 118. In alternative implementations, the adaptor flange 102 can be fluidically coupled between the gate valves 310c and 310d, as described with further details below in FIG. 6, or the gate valves 310c and 310d can be fluidically coupled between the adaptor flange 102 and the tubing spool inlet. FIG. 3B is a schematic diagram of flowing chemicals through the wellbore chemical injection assembly of FIG. 3A. Using the wellbore chemical injection system 200 (FIG. 2), chemicals from the chemical reservoir 202 (FIG. 2) are flowed through the chemical line 204 (FIG. 2) into the inlet of the tubing spool 118 and into the annulus between the production tubing 104 and the inner wall of the intermediate casing 304, as schematically shown by the arrow 318.

[0027] FIG. 4A illustrate a cross-section view of the example adaptor flange 102 implemented in FIGS. 1A-3B. FIG. 4B illustrates side views of two ends of the example adaptor flange 102. For ease of description, reference will be made to both FIGS. 4A and 1B when describing the structure of the adaptor flange 102. As shown in FIG. 4A, the adaptor flange 102 includes a body 420. The body 420 defines a through opening 406. The body 420 includes a first portion 402, a second portion 404 that is opposite the first portion 402, and a neck portion 414 connecting the first portion 402 to the second portion 404. The first portion 402 terminates at a first end 401 of the adaptor flange 102. The second portion 404 terminates at a second end 403 of the adaptor flange 102. The second end 403 is opposite the first end 401 along a longitudinal direction of the through opening 406, e.g., x-direction.

[0028] The through opening 406 has varying inner diameters. The first portion 402 defines a first inner diameter 410a of the through opening 406. The second portion 404 defines a second inner diameter 410b of the through opening 406. The second inner diameter 410b is smaller than the first inner diameter 410a of the through opening 406. In the neck portion 414, the inner diameter of the through opening 406 transitions from the first inner diameter 410a to the second Inner diameter 410b along a longitudinal length of the neck portion, e.g., x-direction.

[0029] The first portion 402 includes an interior valve removal (VR) plug profile 408 to receive a solid VR plug or a check valve type VR plug. The VR plug profile 408 can be defined by the American Petroleum Institute (API) SPEC 6A standard. The VR plug profile 408 can be configured to accommodate for the installation of a VR plug or a threaded check valve. VR plugs, e.g., VR plug 482 as illustrated in FIG. 4D below, can provide a mechanical barrier to isolate the annulus pressure in order to, for example, safely replace a damaged gate valve. Check valves, e.g., check valves 424 as illustrated in FIG. 4C below, can reduce contamination, damage or safety hazards from reverse flows, as described with further details below in FIG. 4C.

[0030] An outer dimension 412a of the first portion 402 is greater than an outer dimension 412b of the second portion 404. In some implementations, the outer dimension 412a of the first portion 402 is a maximum distance between two opposite outer edges of the first portion 402. Similarly, the outer dimension 412b of the second portion 404 is a maximum distance between two opposite outer edges of the second portion 404. For example, as illustrated in FIG. 4B, the first portion 402 and the second portion 404 can have a circular cross-section shape. The outer dimension 412a of the first portion 402 can be its outer diameter, which is greater than an outer diameter 412b of the second portion 404. In some implementations, the first portion 402 and the second portion 404 have a rectangular cross-section shape (not shown). The outer diameter can be the length or the width of the rectangle.

[0031] In some implementations, as illustrated in FIGS. 4A-4B, the first portion 402 defines first holes 416a which are evenly spaced in a first circle 442a around the perimeter to align with corresponding holes on the mating flange or component. Likewise, the second portion 404 defines second holes 416b evenly spaced in a second circle 442b. The holes 416a, 416b can be configured to receive bolts. The circle 442a, 442b can pass through the centers of the holes, as shown in FIG. 4B. In some implementations, the first circle 442a has a greater diameter than that of the second circle 442b.

[0032] In some implementations, the first holes 416a are configured to receive first bolts that couples the adaptor flange 102 to a gate valve configured to be fluidically coupled to a chemical reservoir 202 (FIG. 2). With greater outer diameter 412a and / or greater circle diameter, the first portion 402 can be fluidically coupled to a larger gate valve, e.g., the gate valve 426. A larger gate valve can accommodate the installation of a larger VR plug or check valve, as during installation a portion of the VR plug or check valve may extend into the gate valve. With the adaptor flange 102, two VR plugs or check valves can be installed: one is in the tubing spool inlet 508 of the wellhead 116, and the other one is in the adaptor flange 102. These two VR plugs or check valves can establish two barriers during the replacement of the gate valve. In certain scenarios, a gate valve is not required. Employing the wellhead 116 and adapter flange 102 may suffice to ensure continuous and secure chemical injection, leading to cost savings by reducing the need for gate valves. The inclusion of a second VR profile can be especially beneficial in situations where the wellhead VR profile 512 is damaged due to various factors such as thread damage, or corrosion.

[0033] In some implementations, the second holes 416b are configured to receive second bolts that couples the adaptor flange 102 to the tubing spool inlet of the wellhead 116 installed at a surface of the wellbore 100 formed through a subterranean zone. In some implementations, the first portion 402 and the second portion 404 also have grooves 418 to match with tongues in the mating components.

[0034] In some implementations, the adaptor flange 102 is a single, unitary structure. In some implementations, the adaptor flange 102 is an assembled structure by attaching the first portion 402, the second portion 404 and the neck portion 414 together via methods, including without limitation to, gluing, bolting, screwing, riveting or welding. The adaptor flange 102 can be made from materials such as carbon steel, stainless steel, alloy steel, or other materials suitable for the wellhead 116 operations.

[0035] FIG. 4C illustrates a schematic view of an example wellbore chemical injection assembly 400. The wellbore chemical injection assembly 400 includes the adaptor flange 102 of FIGS. 4A-4B. The wellbore chemical injection assembly 400 also includes a threaded check valve 424 with an exterior plug profile that engages with the VR plug profile 408 of the adaptor flange 102. The exterior plug profile of the check valve 424 can be metal threads that matches with the VR plug profile 408. Check valves (also called non-return valves or one-way valves) can be configured to channel fluid flow along a singular direction. For example, the check valve 424 can direct the chemicals from the chemical reservoir 202 (FIG. 2) to the wellhead 116 (FIG. 2), while preventing reverse formation fluid flow from downhole wellbore 100 to the first gate valve 426. Check valves may reduce contamination, damage or safety hazards from reverse flows. They may also help establish a fail-safe barrier, particularly in situations where injection demands high pressure. For example, in some situations, injection pressure and / or wellhead pressure can exceed 5,000 psi (3.4e7 Pascals). The check valve can automatically isolate wells if there is a rupture, breakout, or damage to the surface chemical injection line, enhancing safety and preventing potential hazards.

[0036] In some implementations, the threaded check valve 424 is removably installed within the adaptor flange 102 by coupling or decoupling its exterior plug profile with the VR plug profile 408 of the adaptor flange 102. Installation and retrieval of the VR plugs or check valves can be achieved using standard lubricators. With VR lubricators, the threaded check valve can be easily installed, removed or replaced without the need for disassembly or separation of the adaptor flange 102. The same adaptor flange can be used repeatedly for multiple installations of check valves, contributing to cost savings and resource efficiency.

[0037] In some implementations, the first portion 402 of the adaptor flange 102 is coupled to a first gate valve 426. The first gate valve 416 can be implemented as the gate valve 310c in FIGS. 3A-3B. As described with further details below in FIG. 6, the first gate valve 426 can be configured to fluidically couple to a chemical reservoir 202 (FIG. 2) from which chemical is injected through the first gate valve 426 and the adaptor flange 102 into the tubing spool inlet. In some implementations, the pressure rating for the adaptor flange 102 is the same as the first gate valve 426. The pressure rating can indicate the maximum pressure at which valves can safely operate without risk of failure. In some implementations, the first gate valve 426 and the adaptor flange 102 have the same pressure ratings ranging from 1000 pounds per square inch (psi) (6.9e6 Pascal) to 10000 psi (6.9e7 Pascal).

[0038] FIG. 4D illustrates a schematic view of the adaptor flange 102 with a VR plug. The VR plug 482 can be installed by engaging with the VR plug profile 408. The VR plug 482 can establish a barrier for replacement of gate valves. For example, this barrier may help contain any potential fluid or pressure release during the valve replacement procedure. Once the VR plug 482 is in place, they may effectively isolate the section of the chemical injection system containing the target gate valves for replacement. This isolation can prevent the escape of fluids or gases. With the area isolated and secured by the VR plug, the removal of the existing gate valve can be accomplished.

[0039] FIG. 5 illustrates a schematic diagram of a tubing spool 118 and the example wellbore chemical injection assembly 400 of FIG. 4C. As illustrated, the tubing spool 118 has a main body 502 with a cylindrical or rectangular structure. The main body 502 can be made of forged steel or cast steel. The tubing spool 118 can also include a tubing hanger 504 which supports the tubing strings and provides a seal between the tubing strings 506 and the spool 118. The tubing strings 506 can be the surface casing 302, the intermediate casing 304, and / or the production tubing 104 in FIGS. 3A-3B. The tubing spool 118 have inlets 508 or outlets on side walls of the main body 502, where the adaptor flange 102 or the gate valves 310a, 310b can be attached to provide access points for auxiliary lines or equipment, such as chemical injection lines. The chemicals can be injected into the tubing spool 118 through the inlets, e.g., the tubing spool inlet 508.

[0040] In some implementations, the side inlets 508 of the tubing spool 118 can include a second VR plug profile 512. The second VR plug profile 512 can be configured to receive a second VR plug (not shown) or a second check valve 516 (also called inlet check valve 516 in this disclosure). In some implementations, all two VR plug profiles 408, 512 have an American Petroleum Institute (API) Sharp Vee VR profile (called “Sharp Vee”) profile that is rated for pressures between 3,000 pounds per square inch (psi) (2.1e7 Pascal) and 10,000 psi (6.9e7 Pascal). The check valves 424, 516 can have exterior plug profiles that engages with the respective VR plug profiles 408, 512 for removable installation and retrieval. The exterior plug profiles can be metal threads. In some situations, the check valves 424, 516 can be installed and kept in the wellhead 116 during operation to direct the chemical along only one direction.

[0041] The adapter flange 102 can be deployed when the wellhead VR profile is damaged due to, e.g., corrosion, or thread damages. Installing the adapter flange 102 with VR profile between wellhead and the first gate valve 426 can provide an internal isolation on the wellhead side outlet port within the system. The check valves 424, 516 can be deployed as two internal fail-stop barriers. As noted above, the check valves 424, 516 can be configured to automatically close under certain conditions. For example, a check valve operates based on the flow of fluid. When fluid flows in the desired direction, e.g., from the chemical reservoir 202 to the wellhead 116 (FIG. 2), the check valve 424 remains open, allowing the fluid to pass through. However, if there is backflow or flow in the opposite direction, e.g., from the wellhead 116 to the chemical reservoir 202 (FIG. 2), the check valve automatically closes to prevent the reverse flow of formation fluid. This function of the check valve can be deployed as a fail-safe barrier for reverse flow. In some situations, a minimum of two fail-safe barriers are required for certain operations. This requirement is intended to enhance safety by ensuring redundancy and reliability in the system. To satisfy this requirement, the fail-safe barriers may be implemented with external safety monitoring systems. However, the external safety monitoring systems may be less reliable in harsh environmental conditions due to exposure to dropped objects or other external hazards. In contrast, the internal check valves 424, 516 installed inside the adaptor flange 102 and the tubing spool 118 are less susceptible to external harsh environmental condition, enhancing the reliability, efficiency, and safety of the chemical injection operation. It is understood that in some implementations, only one internal fail-safe barrier is deployed, e.g., the first check valve 424.

[0042] FIG. 6 illustrates a schematic view of the example adaptor flange 102 implemented between two gate valves. As illustrated, the first portion 402 of the adaptor flange 102 can be fluidically coupled to the first gate valve 426. The second portion 404 of the adaptor flange 102 can be fluidically coupled to a second gate valve 604. The second gate valve 604 can be fluidically coupled to the tubing spool inlet 508 of a wellhead 116 installed at a surface of a wellbore 100 formed through a subterranean zone. The tubing spool inlet 508 can include the inlet check valve 516 (FIG. 5). The first gate valve 426 can be fluidically coupled to a chemical reservoir 202 (FIG. 2) from which chemical is injected through the first gate valve 426, the adaptor flange 102 and the second gate valve 604 into the tubing spool inlet 508.

[0043] As noted above, as the first portion 402 of the adaptor flange 102 has a greater outer diameter 412a (FIGS. 4A-4B) than that of the second portion 404, the first portion 402 of the adaptor flange 102 can be coupled to a larger gate valve. Therefore, the first gate valve 426 can have a larger size than the second gate valve 604, as illustrated in FIG. 6. Larger valves can allow high chemical flow rates or large volumes of chemical fluid, enhancing chemical injection efficiency.

[0044] FIG. 6 also illustrates a chemical flow direction (arrow 602) through the adaptor flange 102. Using the wellbore chemical injection assembly 400 (FIG. 4C), chemicals from the chemical reservoir 202 (FIG. 2) are flowed through the chemical line 204 (FIG. 2) into the first gate valve 426, the first check valve 425 of the adaptor flange 102, the second gate valve 604, and the inlet 508 of the tubing spool 118, and into the annulus between the production tubing 104 and the inner wall of the intermediate casing 304, as schematically shown by the arrow 602.

[0045] FIG. 7 illustrates an example process 700 to inject chemicals through a tubing spool side adaptor flange 102. At step 702, an adaptor flange is provided. The adaptor flange can be, e.g., any one of the adaptor flange 102 of FIGS. 4A-4D. As illustrated in FIG. 4A, the adaptor flange 102 includes a body 420 and the body 420 defines a through opening 406. The body 420 includes a first portion 402, a second portion 404 opposite the second portion 404, and a neck portion 414 connecting the first portion 402 to the second portion 404. The through opening 406 has a greater inner diameter 410a at the first portion 402 compared to the inner diameter 410b at the second portion 404. In the neck portion 414, the inner diameter of the through opening 406 transitions from the first inner diameter 410a to the second inner diameter 410b along a longitudinal length of the neck portion 414. The first portion 402 includes a valve removal (VR) plug profile 408 to receive a check valve, e.g., the first check valve 424, or a VR plug. An outer dimension 412 of the first portion 402 is greater than an outer dimension 412 of the second portion 404.

[0046] At step 704, the first portion 402 of the adaptor flange 102 is fluidically coupled to a first gate valve 426, as illustrated in FIGS. 1A-3B and 5-6. The first gate valve 426 is configured to be fluidically coupled to a chemical reservoir 202 (FIG. 2).

[0047] At step 706, the second portion 404 of the adaptor flange 102 is fluidically coupled to a tubing spool inlet 508 of a wellhead 116 installed at a surface of a wellbore 100 formed through a subterranean zone, as illustrated in FIGS. 1A-3B and 5-6.

[0048] At step 708, chemicals are injected through the first gate valve 426 and the adaptor flange 102 into the tubing spool inlet 508.

[0049] At step 710, in some implementations, a first VR plug is installed in the tubing spool inlet 508 of the wellhead 116, and a first inflow test is performed to assess effectiveness of isolation provided by the first VR plug. For example, when a tubing spool side gate valve, e.g., the gate valve 426, needs be replaced, the first VR plug may be installed in the tubing spool inlet 508 of the wellhead 116 for isolation purpose. To assess the effectiveness of isolation provided by the first VR plug, an inflow test can be performed. During the inflow test, the pressure downstream of the first VR plug can be reduced, e.g., from 4,000 psi (2.7e7 Pascals) to 50-100 psi (3.4e5-6.9e5 Pascals). The pressure can be then monitored for 15 mins. If there is no pressure buildup or visual leak observed during this period, it may indicate that the first VR plug is effectively holding.

[0050] At step 712, in some implementations, a second VR plug is installed in the adaptor flange 102, and a second inflow test is performed to assess effectiveness of isolation provided by the second VR plug. Before installing the second VR plug, pressure needs to be maintained (e.g., 500 psi or 3.4e6 Pascals) between the first VR plug and the second VR plug (e.g., upstream side of the second VR plug). After setting the second VR plug, the pressure downstream of the second VR plug can be released during the second inflow test, and the pressure buildup or any visual leak can be monitored, as described above. The second VR plug can be, e.g., the VR plug 482 of FIG. 4D.

[0051] In some implementations, coupling the second portion 404 of the adaptor flange 102 to the tubing spool inlet 508 of the wellhead 116 includes coupling the second portion 404 of the adaptor flange 102 to a second gate valve 604 (FIG. 6) and coupling the second gate valve 604 to the tubing spool inlet 508 of the wellhead 116. The first gate valve 426 can be bigger than the second gate valve 604, as illustrated in FIG. 6.

[0052] In some implementations, a first check valve is installed in the tubing spool inlet of the wellhead. The first check valve can be, e.g., the second check valve 516 of FIG. 5. The tubing spool inlet can be, e.g., the tubing spool inlet 508 of FIG. 5. The wellhead can be, e.g., the wellhead 116 of FIGS. 1A-3B and 6.

[0053] In some implementations, a second check valve is installed in the first portion of the adaptor flange. The second check valve can be, e.g., the first check valve 424 of FIGS. 4C and 5.Implementations

[0054] Certain aspects of the subject matter described here can be implemented as an adaptor flange. The adaptor flange includes a body defining a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening. The body includes a neck portion connecting the first portion to the second portion. An inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion.

[0055] An aspect combinable with any other aspect includes the following features. The adaptor flange includes a single, unitary structure.

[0056] An aspect combinable with any other aspect includes the following features. The outer dimension of the first portion is a maximum distance between two opposite outer edges of the first portion, and the outer dimension of the second portion is a maximum distance between two opposite outer edges of the second portion.

[0057] An aspect combinable with any other aspect includes the following features. Each of the first portion and the second portion has a circular shape. The outer dimension of the first portion is an outer diameter of the first portion, and the outer dimension of the second portion is an outer diameter of the second portion.

[0058] An aspect combinable with any other aspect includes the following features. The first portion of the adaptor flange defines a plurality of first holes evenly spaced in a first circle. The second portion of the adaptor flange defines a plurality of second holes evenly spaced in a second circle. A diameter of the first circle is greater than a diameter of the second circle.

[0059] An aspect combinable with any other aspect includes the following features. The first holes are configured to receive first bolts that couple the adaptor flange to a gate valve configured to be fluidically coupled to a chemical reservoir.

[0060] An aspect combinable with any other aspect includes the following features. The second holes are configured to receive second bolts that couple the adaptor flange to a tubing spool inlet of a wellhead installed at a surface of a wellbore formed through a subterranean zone.

[0061] An aspect combinable with any other aspect includes the following features. The VR plug profile is configured to receive a VR plug or a check valve.

[0062] Certain aspects of the subject matter described here can be implemented as a wellbore chemical injection assembly. The wellbore chemical injection assembly includes a body defining a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening. The body includes a neck portion connecting the first portion to the second portion. An inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion. The wellbore chemical injection assembly includes a check valve that includes an exterior plug profile that engages with the VR plug profile of the adaptor flange.

[0063] An aspect combinable with any other aspect includes the following features. The outer dimension of the first portion is a maximum distance between two opposite outer edges of the first portion, and the outer dimension of the second portion is a maximum distance between two opposite outer edges of the second portion.

[0064] An aspect combinable with any other aspect includes the following features. Each of the first portion and the second portion has a circular shape. The outer dimension of the first portion is an outer diameter of the first portion, and the outer dimension of the second portion is an outer diameter of the second portion.

[0065] An aspect combinable with any other aspect includes the following features. The check valve is configured to be removably installed within the adaptor flange.

[0066] An aspect combinable with any other aspect includes the following features. The first portion of the adaptor flange defines a plurality of first holes evenly spaced in a first circle. The second portion of the adaptor flange defines a plurality of second holes evenly spaced in a second circle. A diameter of the first circle is greater than a diameter of the second circle.

[0067] Certain aspects of the subject matter described here can be implemented as a method. The method includes providing an adaptor flange including a body defining a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening. The body includes a neck portion connecting the first portion to the second portion. An inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion. The method includes coupling the first portion of the adaptor flange to a first gate valve configured to be fluidically coupled to a chemical reservoir; coupling the second portion of the adaptor flange to a tubing spool inlet of a wellhead installed at a surface of a wellbore formed through a subterranean zone; and injecting chemicals through the first gate valve and the adaptor flange into the tubing spool inlet.

[0068] An aspect combinable with any other aspect includes the following features. Coupling the second portion of the adaptor flange to the tubing spool inlet of the wellhead includes: coupling the second portion of the adaptor flange to a second gate valve; and coupling the second gate valve to the tubing spool inlet of the wellhead.

[0069] An aspect combinable with any other aspect includes the following features. A first check valve is installed in the tubing spool inlet of the wellhead.

[0070] An aspect combinable with any other aspect includes the following features. A second check valve is installed in the adaptor flange.

[0071] An aspect combinable with any other aspect includes the following features. A first VR plug is installed in the tubing spool inlet of the wellhead.

[0072] An aspect combinable with any other aspect includes the following features. An inflow test is performed to assess effectiveness of isolation provided by the first VR plug.

[0073] An aspect combinable with any other aspect includes the following features. A second VR plug is installed in the adaptor flange.

[0074] Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. Moreover, aspects described with reference to any figure or any implementation can be combined with aspects described with any other figure or any other implementation.

[0075] It is understood that the articles “a,”“an,” and “the” in this disclosure are intended to mean that there are one or more of the elements in the preceding descriptions. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one example” or “an example” of the present disclosure are not intended to be interpreted as excluding the existence of additional examples that also incorporate the recited features. For example, any element described in relation to an example herein may be combinable with any element of any other example described herein. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about” or “approximately” the stated value, as would be appreciated by one of ordinary skill in the art encompassed by examples of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable manufacturing or production process, and may include values that are within 5%, within 1%, within 0.1%, or within 0.01% of a stated value.

[0076] A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made to examples disclosed herein without departing from the spirit and scope of the present disclosure. Equivalent constructions, including functional “means-plus-function” clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words ‘means for’ appear together with an associated function. Each addition, deletion, and modification to the examples that falls within the meaning and scope of the claims is to be embraced by the claims.

[0077] The terms “approximately,”“about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,”“about,” and “substantially” may refer to an amount that is within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount. Further, it should be understood that any directions or reference frames in the preceding description are merely relative directions or movements. For example, any references to “up” and “down” or “above” or “below” are merely descriptive of the relative position or movement of the related elements.

Examples

Embodiment Construction

[0017]Hydrocarbons entrapped in subsurface reservoirs flow from the reservoirs through the subterranean zone into the wellbore formed in the subterranean zone. Wellbore equipment are installed within the wellbore to produce the hydrocarbons to the surface. The fluids, e.g., high saline formation brines, various mixtures of oil and mixtures of gas (such as natural gas, hydrogen sulfide, carbon dioxide) that flow into the wellbore through the subterranean zone are extremely corrosive. The wellbore equipment, e.g., tubulars, packers, and the like, can be adversely impacted by the long-term contact with such fluids. For example, the equipment can corrode, or scales or sludges can build up on the equipment or both. The adverse impact on the wellbore equipment, in turn, can impact well production, well integrity, surface production facilities and the like. The adverse impact of the wellbore fluids can be reduced by flowing (i.e., injecting or pumping) chemical inhibitors into the wellbore...

TECHNICAL FIELD

[0001] The present disclosure relates to wellbore chemical injection and specifically to injection from a surface of the wellbore through a wellhead.BACKGROUND

[0002] Wellbore operations utilize well tools installed within a wellbore formed in a subterranean zone (e.g., a formation, a portion of a formation, multiple formations). Fluids (e.g., drilling mud) used during wellbore formation or hydrocarbons (e.g., petroleum, natural gas, combinations of them) produced through the wellbore after formation and completion can corrode the well tools. Chemicals, such as corrosion inhibitors, scale inhibitors, emulsion preventive inhibitors, asphaltene inhibitor, to name a few, can be injected from a surface of the wellbore into the wellbore (e.g., into a wellbore-tubing annulus) to minimize such corrosive effect of fluids that flow through the wellbore. The chemicals can be injected using a chemical injection system that is installed at the surface of the wellbore. The chemical injection system can be fluidically coupled to the wellhead, specifically to the wellhead to inject the chemicals through a tubing spool, which is a component of the wellhead.SUMMARY

[0003] The present disclosure describes methods, devices, systems and techniques for wellbore chemical injection adaptor flange system through tubing spool side outlet port.

[0004] The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIGS. 1A, 1B and 1C are examples of different arrangements to inject chemicals into a wellbore using an adaptor flange described in this disclosure.

[0006] FIG. 2 illustrates a schematic diagram of a wellbore chemical injection system disposed at a surface of a wellbore.

[0007] FIG. 3A illustrates a schematic diagram of a wellhead including a tubing spool to which an example implementation of a wellbore chemical injection system is connected.

[0008] FIG. 3B illustrates a schematic diagram of flowing chemicals through the adaptor flange of FIG. 3A.

[0009] FIG. 4A illustrates a cross-section view of an example adaptor flange.

[0010] FIG. 4B illustrates side views of two ends of the example adaptor flange.

[0011] FIG. 4C illustrates a schematic view of an example wellbore chemical injection assembly.

[0012] FIG. 4D illustrates a schematic view of an example adaptor flange with a VR plug.

[0013] FIG. 5 illustrates a schematic diagram of a tubing spool and the example wellbore chemical injection assembly of FIG. 4C.

[0014] FIG. 6 illustrates a schematic view of an implementation of the example adaptor flange between two gate valves.

[0015] FIG. 7 illustrates an example process to inject chemicals through the example adaptor flange.

[0016] It is to be understood that the various exemplary implementations shown in the figures are merely illustrative representations and are not necessarily drawn to scale.DETAILED DESCRIPTION

[0017] Hydrocarbons entrapped in subsurface reservoirs flow from the reservoirs through the subterranean zone into the wellbore formed in the subterranean zone. Wellbore equipment are installed within the wellbore to produce the hydrocarbons to the surface. The fluids, e.g., high saline formation brines, various mixtures of oil and mixtures of gas (such as natural gas, hydrogen sulfide, carbon dioxide) that flow into the wellbore through the subterranean zone are extremely corrosive. The wellbore equipment, e.g., tubulars, packers, and the like, can be adversely impacted by the long-term contact with such fluids. For example, the equipment can corrode, or scales or sludges can build up on the equipment or both. The adverse impact on the wellbore equipment, in turn, can impact well production, well integrity, surface production facilities and the like. The adverse impact of the wellbore fluids can be reduced by flowing (i.e., injecting or pumping) chemical inhibitors into the wellbore. The chemicals can be pumped from a surface of the wellbore continuously to downhole locations, specifically to the area of the designed target depth.

[0018] This disclosure describes This disclosure describes a wellbore chemical injection assembly with an adaptor flange that can be coupled to a tubing spool inlet of a wellhead of a wellbore formed in a subterranean zone. In some aspects, an adaptor flange includes a body. The body defines a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening. The body further includes a neck portion connecting the first portion to the second portion. An inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion.

[0019] Implementations of the present disclosure can provide one or more of the following technical advantages. For example, the techniques described here can improve efficiency and safety of wellbore chemical injection operations by deploying internal fail-safe systems. Particularly, the techniques described are mechanical solutions that can be deployed with lesser resource consumption compared to smart solutions that implement pneumatic, hydraulic or electrical actuators. The adaptor flange has two ends with unequal outer diameters. The larger end can be coupled to a larger gate valve. A larger gate valve can allow the installation of a larger VR plug or check valve, as during installation a portion of the VR plug or check valve may extend into the gate valve. Therefore, with a larger gate valve and the adaptor flange, two VR plugs or check valves can be installed at side ports of a wellhead. These two VR plugs or check valves can establish two barrier during the replacement of the gate valve. In some implementations, a check valve is installed in the adaptor flange, which prevents backflow or the reverse flow of formation fluids through the tubing spool gate valve. This ensures that formation-related gases and corrosive fluids are unable to reach the gate valve, thereby enhancing operational lifespan of the gate valve. Installing check valve type VR plug in the tubing spool or in the flange setup is much more safer application that installing check valves out of the wellhead. Moreover, the arrangement of the VR plug profile allows easy installation, removal or replacement of a VR plug or a threaded check valve. When the adaptor flange is deployed with a VR plug, the adaptor flange can serve as a barrier that facilitates replacing gate valves on the side outlet of the tubing spool. Depending on the well type and wellhead pressures, one or two barriers may be required during gate valve replacement. If only one barrier is needed, the VR plug can be utilized and installed directly into the outlet or inlet port VR profile of the wellhead. If two barriers are required, another VR plug may be installed into the adapter flange VR profile.

[0020] FIGS. 1A, 1B and IC are examples of different arrangements to inject chemicals into a wellbore 100 using the adaptor flange 102 described in this disclosure. The arrangements can be implemented to inject chemicals into a tubing annulus to transfer the chemicals to downhole locations within the wellbore 100. FIG. 1A shows a schematic arrangement of using the adaptor flange 102 to inject chemicals into a downhole location in the wellbore 100 for flow in an uphole direction through a production tubing104 to the surface. The wellbore 100 is formed in a subterranean zone 106. The wellbore 100 can be cased and cemented 108 or can be non-cement cased or partially cased. Perforations 110 formed in the wellbore wall allow hydrocarbons to flow from the subterranean zone 106 into the wellbore 100. Packers 112 can be installed near a downhole end of the production tubing 104 to isolate a region of the wellbore 100 below the packers 112 from a region above the packers 112. The hydrocarbons flow from the subterranean zone 106 in an uphole direction (arrows 114) towards a downhole inlet of the production tubing 104 and towards the surface of the wellbore 100.

[0021] At the surface, a wellhead assembly can be installed to deploy wellbore equipment (including the production tubing 104, the packers 112, etc.) within the wellbore 100, and also to serve as a connection point for surface equipment. The wellhead assembly can include a wellhead 116, which is a network of fluidic inlets, outlets and flow control equipment (such as valves) to which the adaptor flange 102 is fluidically coupled. In particular, the adaptor flange 102 can be fluidically coupled to an inlet formed in a tubing spool 118 of the wellhead 116. A control line 120 (e.g., a tubing or a pipe) extends from the tubing spool 118 to a downhole location that is downhole of the inlet to the production tubing 104. For example, the control line 120 can pass through an annulus formed by the production tubing 104 and the casing installed in or inner wall of the wellbore 100, and through the packers 112. Chemicals can be injected from the surface of the wellbore 100 through the control line 120 to the downhole location. The injected chemicals are flowed in an uphole direction (arrows 122) by the hydrocarbons and swept into the production tubing 104. As the chemicals flow towards the surface, the chemicals contact the wellbore equipment (such as the inner walls of the production tubing 104) to prevent, reduce or reverse the adverse effects mentioned earlier.

[0022] FIG. 1B shows another schematic arrangement of using the adaptor flange 102 to inject chemicals into a downhole location in the wellbore 100 for flow in an uphole direction through a production tubing 104 to the surface. The arrangement of FIG. 1B is substantially identical to that of FIG. 1A, except that the arrangement of FIG. 1B does not implement the packers 112 (FIG. 1A). The arrangement of FIG. 1B allows monitoring annulus pressure behind the production tubing 104, which helps to monitor liquid loading condition of the wellbore 100. FIG. 1C shows another schematic arrangement of using the adaptor flange 102 to inject chemicals into a downhole location in the wellbore 100 for flow in an uphole direction through a production tubing 104 to the surface. The arrangement of FIG. 1C is substantially identical to that of FIG. 1A, except that the arrangement of FIG. 1C does not implement the control line 120 and does not implement packers. Instead, the chemicals are injected from the surface, through the tubing spool 118, directly into the annulus. The chemicals will travel downhole through the annulus and enter the production tubing 104 with the hydrocarbons. The wellbore chemical injection adaptor flange 102 can be used to inject chemicals in any of the arrangements shown in FIGS. 1A-C or other arrangements in which wellbore equipment installed within a wellbore needs to be treated with chemicals injected from the surface.

[0023] FIG. 2 shows a schematic diagram of a wellbore chemical injection system 200 disposed at a surface of the wellbore 100. The system 200 is shown as being implemented with the wellbore 100 described with reference to FIG. 1C. However, the system 200 is useable with any of the arrangements shown in FIGS. 1A, 1B and IC or other arrangements in which wellbore equipment need chemical treatment. The system 200 includes a chemical reservoir 202 (e.g., a tank) that stores the chemical or chemicals to be injected into the wellbore 100. A chemical line 204 (e.g., tubing or pipe) fluidically couples the reservoir 202 to the adaptor flange 102. Flow through the chemical line 204 is implemented using a pump 206 (e.g., a high pressure pump) and flow control equipment (e.g., control valves 208a, 208b) fluidically coupled along the length of the chemical line 204. One or more of the control valves (e.g., control valves 208b) can be installed near and fluidically coupled to the wellbore chemical injection adaptor flange 102. The adaptor flange 102 is fluidically coupled to an inlet of the tubing spool 118 of the wellhead 116.

[0024] The adaptor flange 102 and the tubing spool inlet can be coupled using valve removal (VR) plug profiles. The VR plug profiles can be an American Petroleum Institute (API) Sharp Vee VR profile (called “Sharp Vee”) profile that is rated for pressures between 3,000 pounds per square inch (psi) (2.1e7 Pascal) and 10,000 psi (6.9e7 Pascal). Tubing spools have API standard VR plug profiles. VR plugs do not stay in installed positions in the side outlet ports at all times. In some situations, the VR plugs can be installed and kept in the wellhead. If the standard VR plug is installed, they fully isolate the side outlet port.

[0025] FIG. 3A is a schematic diagram of a wellhead 116 including a tubing spool 118 to which an example implementation of a wellbore chemical injection system is connected. The wellhead 116 can be attached to different types of tubings installed within the wellbore, e.g., a surface casing 302, an intermediate casing 304, the production tubing 104. The wellhead 116 can include multiple spools including a top tubing spool 118, a first casing spool 306 and a second casing spool 308. Each spool can be fluidically coupled to one of the tubings or casing installed within the wellbore 100. The top tubing spool 118 can be fluidically coupled to the production tubing 104. Each spool can be fluidically coupled to respective gate valves, e.g., gate valves 310a, 310b, 310c, 310d fluidically coupled to the top tubing spool 118, gate valves 312a, 312b fluidically coupled to the first casing spool 306, gate valves 312c, 312d fluidically coupled to the second casing spool 308. The gate valves coupled to the spools can include outlets that can couple to flow equipment (such as tubings) using which fluid flow into or out of the respective spools can be controlled. A production tree 314 is installed above the top tubing spool 118 and can be fluidically coupled to the top tubing spool 118 through a gate valve 316.

[0026] In some implementations, the adaptor flange 102 can be fluidically coupled to the top tubing spool 118 between the gate valve 310c and an inlet to the tubing spool 118. In alternative implementations, the adaptor flange 102 can be fluidically coupled between the gate valves 310c and 310d, as described with further details below in FIG. 6, or the gate valves 310c and 310d can be fluidically coupled between the adaptor flange 102 and the tubing spool inlet. FIG. 3B is a schematic diagram of flowing chemicals through the wellbore chemical injection assembly of FIG. 3A. Using the wellbore chemical injection system 200 (FIG. 2), chemicals from the chemical reservoir 202 (FIG. 2) are flowed through the chemical line 204 (FIG. 2) into the inlet of the tubing spool 118 and into the annulus between the production tubing 104 and the inner wall of the intermediate casing 304, as schematically shown by the arrow 318.

[0027] FIG. 4A illustrate a cross-section view of the example adaptor flange 102 implemented in FIGS. 1A-3B. FIG. 4B illustrates side views of two ends of the example adaptor flange 102. For ease of description, reference will be made to both FIGS. 4A and 1B when describing the structure of the adaptor flange 102. As shown in FIG. 4A, the adaptor flange 102 includes a body 420. The body 420 defines a through opening 406. The body 420 includes a first portion 402, a second portion 404 that is opposite the first portion 402, and a neck portion 414 connecting the first portion 402 to the second portion 404. The first portion 402 terminates at a first end 401 of the adaptor flange 102. The second portion 404 terminates at a second end 403 of the adaptor flange 102. The second end 403 is opposite the first end 401 along a longitudinal direction of the through opening 406, e.g., x-direction.

[0028] The through opening 406 has varying inner diameters. The first portion 402 defines a first inner diameter 410a of the through opening 406. The second portion 404 defines a second inner diameter 410b of the through opening 406. The second inner diameter 410b is smaller than the first inner diameter 410a of the through opening 406. In the neck portion 414, the inner diameter of the through opening 406 transitions from the first inner diameter 410a to the second Inner diameter 410b along a longitudinal length of the neck portion, e.g., x-direction.

[0029] The first portion 402 includes an interior valve removal (VR) plug profile 408 to receive a solid VR plug or a check valve type VR plug. The VR plug profile 408 can be defined by the American Petroleum Institute (API) SPEC 6A standard. The VR plug profile 408 can be configured to accommodate for the installation of a VR plug or a threaded check valve. VR plugs, e.g., VR plug 482 as illustrated in FIG. 4D below, can provide a mechanical barrier to isolate the annulus pressure in order to, for example, safely replace a damaged gate valve. Check valves, e.g., check valves 424 as illustrated in FIG. 4C below, can reduce contamination, damage or safety hazards from reverse flows, as described with further details below in FIG. 4C.

[0030] An outer dimension 412a of the first portion 402 is greater than an outer dimension 412b of the second portion 404. In some implementations, the outer dimension 412a of the first portion 402 is a maximum distance between two opposite outer edges of the first portion 402. Similarly, the outer dimension 412b of the second portion 404 is a maximum distance between two opposite outer edges of the second portion 404. For example, as illustrated in FIG. 4B, the first portion 402 and the second portion 404 can have a circular cross-section shape. The outer dimension 412a of the first portion 402 can be its outer diameter, which is greater than an outer diameter 412b of the second portion 404. In some implementations, the first portion 402 and the second portion 404 have a rectangular cross-section shape (not shown). The outer diameter can be the length or the width of the rectangle.

[0031] In some implementations, as illustrated in FIGS. 4A-4B, the first portion 402 defines first holes 416a which are evenly spaced in a first circle 442a around the perimeter to align with corresponding holes on the mating flange or component. Likewise, the second portion 404 defines second holes 416b evenly spaced in a second circle 442b. The holes 416a, 416b can be configured to receive bolts. The circle 442a, 442b can pass through the centers of the holes, as shown in FIG. 4B. In some implementations, the first circle 442a has a greater diameter than that of the second circle 442b.

[0032] In some implementations, the first holes 416a are configured to receive first bolts that couples the adaptor flange 102 to a gate valve configured to be fluidically coupled to a chemical reservoir 202 (FIG. 2). With greater outer diameter 412a and / or greater circle diameter, the first portion 402 can be fluidically coupled to a larger gate valve, e.g., the gate valve 426. A larger gate valve can accommodate the installation of a larger VR plug or check valve, as during installation a portion of the VR plug or check valve may extend into the gate valve. With the adaptor flange 102, two VR plugs or check valves can be installed: one is in the tubing spool inlet 508 of the wellhead 116, and the other one is in the adaptor flange 102. These two VR plugs or check valves can establish two barriers during the replacement of the gate valve. In certain scenarios, a gate valve is not required. Employing the wellhead 116 and adapter flange 102 may suffice to ensure continuous and secure chemical injection, leading to cost savings by reducing the need for gate valves. The inclusion of a second VR profile can be especially beneficial in situations where the wellhead VR profile 512 is damaged due to various factors such as thread damage, or corrosion.

[0033] In some implementations, the second holes 416b are configured to receive second bolts that couples the adaptor flange 102 to the tubing spool inlet of the wellhead 116 installed at a surface of the wellbore 100 formed through a subterranean zone. In some implementations, the first portion 402 and the second portion 404 also have grooves 418 to match with tongues in the mating components.

[0034] In some implementations, the adaptor flange 102 is a single, unitary structure. In some implementations, the adaptor flange 102 is an assembled structure by attaching the first portion 402, the second portion 404 and the neck portion 414 together via methods, including without limitation to, gluing, bolting, screwing, riveting or welding. The adaptor flange 102 can be made from materials such as carbon steel, stainless steel, alloy steel, or other materials suitable for the wellhead 116 operations.

[0035] FIG. 4C illustrates a schematic view of an example wellbore chemical injection assembly 400. The wellbore chemical injection assembly 400 includes the adaptor flange 102 of FIGS. 4A-4B. The wellbore chemical injection assembly 400 also includes a threaded check valve 424 with an exterior plug profile that engages with the VR plug profile 408 of the adaptor flange 102. The exterior plug profile of the check valve 424 can be metal threads that matches with the VR plug profile 408. Check valves (also called non-return valves or one-way valves) can be configured to channel fluid flow along a singular direction. For example, the check valve 424 can direct the chemicals from the chemical reservoir 202 (FIG. 2) to the wellhead 116 (FIG. 2), while preventing reverse formation fluid flow from downhole wellbore 100 to the first gate valve 426. Check valves may reduce contamination, damage or safety hazards from reverse flows. They may also help establish a fail-safe barrier, particularly in situations where injection demands high pressure. For example, in some situations, injection pressure and / or wellhead pressure can exceed 5,000 psi (3.4e7 Pascals). The check valve can automatically isolate wells if there is a rupture, breakout, or damage to the surface chemical injection line, enhancing safety and preventing potential hazards.

[0036] In some implementations, the threaded check valve 424 is removably installed within the adaptor flange 102 by coupling or decoupling its exterior plug profile with the VR plug profile 408 of the adaptor flange 102. Installation and retrieval of the VR plugs or check valves can be achieved using standard lubricators. With VR lubricators, the threaded check valve can be easily installed, removed or replaced without the need for disassembly or separation of the adaptor flange 102. The same adaptor flange can be used repeatedly for multiple installations of check valves, contributing to cost savings and resource efficiency.

[0037] In some implementations, the first portion 402 of the adaptor flange 102 is coupled to a first gate valve 426. The first gate valve 416 can be implemented as the gate valve 310c in FIGS. 3A-3B. As described with further details below in FIG. 6, the first gate valve 426 can be configured to fluidically couple to a chemical reservoir 202 (FIG. 2) from which chemical is injected through the first gate valve 426 and the adaptor flange 102 into the tubing spool inlet. In some implementations, the pressure rating for the adaptor flange 102 is the same as the first gate valve 426. The pressure rating can indicate the maximum pressure at which valves can safely operate without risk of failure. In some implementations, the first gate valve 426 and the adaptor flange 102 have the same pressure ratings ranging from 1000 pounds per square inch (psi) (6.9e6 Pascal) to 10000 psi (6.9e7 Pascal).

[0038] FIG. 4D illustrates a schematic view of the adaptor flange 102 with a VR plug. The VR plug 482 can be installed by engaging with the VR plug profile 408. The VR plug 482 can establish a barrier for replacement of gate valves. For example, this barrier may help contain any potential fluid or pressure release during the valve replacement procedure. Once the VR plug 482 is in place, they may effectively isolate the section of the chemical injection system containing the target gate valves for replacement. This isolation can prevent the escape of fluids or gases. With the area isolated and secured by the VR plug, the removal of the existing gate valve can be accomplished.

[0039] FIG. 5 illustrates a schematic diagram of a tubing spool 118 and the example wellbore chemical injection assembly 400 of FIG. 4C. As illustrated, the tubing spool 118 has a main body 502 with a cylindrical or rectangular structure. The main body 502 can be made of forged steel or cast steel. The tubing spool 118 can also include a tubing hanger 504 which supports the tubing strings and provides a seal between the tubing strings 506 and the spool 118. The tubing strings 506 can be the surface casing 302, the intermediate casing 304, and / or the production tubing 104 in FIGS. 3A-3B. The tubing spool 118 have inlets 508 or outlets on side walls of the main body 502, where the adaptor flange 102 or the gate valves 310a, 310b can be attached to provide access points for auxiliary lines or equipment, such as chemical injection lines. The chemicals can be injected into the tubing spool 118 through the inlets, e.g., the tubing spool inlet 508.

[0040] In some implementations, the side inlets 508 of the tubing spool 118 can include a second VR plug profile 512. The second VR plug profile 512 can be configured to receive a second VR plug (not shown) or a second check valve 516 (also called inlet check valve 516 in this disclosure). In some implementations, all two VR plug profiles 408, 512 have an American Petroleum Institute (API) Sharp Vee VR profile (called “Sharp Vee”) profile that is rated for pressures between 3,000 pounds per square inch (psi) (2.1e7 Pascal) and 10,000 psi (6.9e7 Pascal). The check valves 424, 516 can have exterior plug profiles that engages with the respective VR plug profiles 408, 512 for removable installation and retrieval. The exterior plug profiles can be metal threads. In some situations, the check valves 424, 516 can be installed and kept in the wellhead 116 during operation to direct the chemical along only one direction.

[0041] The adapter flange 102 can be deployed when the wellhead VR profile is damaged due to, e.g., corrosion, or thread damages. Installing the adapter flange 102 with VR profile between wellhead and the first gate valve 426 can provide an internal isolation on the wellhead side outlet port within the system. The check valves 424, 516 can be deployed as two internal fail-stop barriers. As noted above, the check valves 424, 516 can be configured to automatically close under certain conditions. For example, a check valve operates based on the flow of fluid. When fluid flows in the desired direction, e.g., from the chemical reservoir 202 to the wellhead 116 (FIG. 2), the check valve 424 remains open, allowing the fluid to pass through. However, if there is backflow or flow in the opposite direction, e.g., from the wellhead 116 to the chemical reservoir 202 (FIG. 2), the check valve automatically closes to prevent the reverse flow of formation fluid. This function of the check valve can be deployed as a fail-safe barrier for reverse flow. In some situations, a minimum of two fail-safe barriers are required for certain operations. This requirement is intended to enhance safety by ensuring redundancy and reliability in the system. To satisfy this requirement, the fail-safe barriers may be implemented with external safety monitoring systems. However, the external safety monitoring systems may be less reliable in harsh environmental conditions due to exposure to dropped objects or other external hazards. In contrast, the internal check valves 424, 516 installed inside the adaptor flange 102 and the tubing spool 118 are less susceptible to external harsh environmental condition, enhancing the reliability, efficiency, and safety of the chemical injection operation. It is understood that in some implementations, only one internal fail-safe barrier is deployed, e.g., the first check valve 424.

[0042] FIG. 6 illustrates a schematic view of the example adaptor flange 102 implemented between two gate valves. As illustrated, the first portion 402 of the adaptor flange 102 can be fluidically coupled to the first gate valve 426. The second portion 404 of the adaptor flange 102 can be fluidically coupled to a second gate valve 604. The second gate valve 604 can be fluidically coupled to the tubing spool inlet 508 of a wellhead 116 installed at a surface of a wellbore 100 formed through a subterranean zone. The tubing spool inlet 508 can include the inlet check valve 516 (FIG. 5). The first gate valve 426 can be fluidically coupled to a chemical reservoir 202 (FIG. 2) from which chemical is injected through the first gate valve 426, the adaptor flange 102 and the second gate valve 604 into the tubing spool inlet 508.

[0043] As noted above, as the first portion 402 of the adaptor flange 102 has a greater outer diameter 412a (FIGS. 4A-4B) than that of the second portion 404, the first portion 402 of the adaptor flange 102 can be coupled to a larger gate valve. Therefore, the first gate valve 426 can have a larger size than the second gate valve 604, as illustrated in FIG. 6. Larger valves can allow high chemical flow rates or large volumes of chemical fluid, enhancing chemical injection efficiency.

[0044] FIG. 6 also illustrates a chemical flow direction (arrow 602) through the adaptor flange 102. Using the wellbore chemical injection assembly 400 (FIG. 4C), chemicals from the chemical reservoir 202 (FIG. 2) are flowed through the chemical line 204 (FIG. 2) into the first gate valve 426, the first check valve 425 of the adaptor flange 102, the second gate valve 604, and the inlet 508 of the tubing spool 118, and into the annulus between the production tubing 104 and the inner wall of the intermediate casing 304, as schematically shown by the arrow 602.

[0045] FIG. 7 illustrates an example process 700 to inject chemicals through a tubing spool side adaptor flange 102. At step 702, an adaptor flange is provided. The adaptor flange can be, e.g., any one of the adaptor flange 102 of FIGS. 4A-4D. As illustrated in FIG. 4A, the adaptor flange 102 includes a body 420 and the body 420 defines a through opening 406. The body 420 includes a first portion 402, a second portion 404 opposite the second portion 404, and a neck portion 414 connecting the first portion 402 to the second portion 404. The through opening 406 has a greater inner diameter 410a at the first portion 402 compared to the inner diameter 410b at the second portion 404. In the neck portion 414, the inner diameter of the through opening 406 transitions from the first inner diameter 410a to the second inner diameter 410b along a longitudinal length of the neck portion 414. The first portion 402 includes a valve removal (VR) plug profile 408 to receive a check valve, e.g., the first check valve 424, or a VR plug. An outer dimension 412 of the first portion 402 is greater than an outer dimension 412 of the second portion 404.

[0046] At step 704, the first portion 402 of the adaptor flange 102 is fluidically coupled to a first gate valve 426, as illustrated in FIGS. 1A-3B and 5-6. The first gate valve 426 is configured to be fluidically coupled to a chemical reservoir 202 (FIG. 2).

[0047] At step 706, the second portion 404 of the adaptor flange 102 is fluidically coupled to a tubing spool inlet 508 of a wellhead 116 installed at a surface of a wellbore 100 formed through a subterranean zone, as illustrated in FIGS. 1A-3B and 5-6.

[0048] At step 708, chemicals are injected through the first gate valve 426 and the adaptor flange 102 into the tubing spool inlet 508.

[0049] At step 710, in some implementations, a first VR plug is installed in the tubing spool inlet 508 of the wellhead 116, and a first inflow test is performed to assess effectiveness of isolation provided by the first VR plug. For example, when a tubing spool side gate valve, e.g., the gate valve 426, needs be replaced, the first VR plug may be installed in the tubing spool inlet 508 of the wellhead 116 for isolation purpose. To assess the effectiveness of isolation provided by the first VR plug, an inflow test can be performed. During the inflow test, the pressure downstream of the first VR plug can be reduced, e.g., from 4,000 psi (2.7e7 Pascals) to 50-100 psi (3.4e5-6.9e5 Pascals). The pressure can be then monitored for 15 mins. If there is no pressure buildup or visual leak observed during this period, it may indicate that the first VR plug is effectively holding.

[0050] At step 712, in some implementations, a second VR plug is installed in the adaptor flange 102, and a second inflow test is performed to assess effectiveness of isolation provided by the second VR plug. Before installing the second VR plug, pressure needs to be maintained (e.g., 500 psi or 3.4e6 Pascals) between the first VR plug and the second VR plug (e.g., upstream side of the second VR plug). After setting the second VR plug, the pressure downstream of the second VR plug can be released during the second inflow test, and the pressure buildup or any visual leak can be monitored, as described above. The second VR plug can be, e.g., the VR plug 482 of FIG. 4D.

[0051] In some implementations, coupling the second portion 404 of the adaptor flange 102 to the tubing spool inlet 508 of the wellhead 116 includes coupling the second portion 404 of the adaptor flange 102 to a second gate valve 604 (FIG. 6) and coupling the second gate valve 604 to the tubing spool inlet 508 of the wellhead 116. The first gate valve 426 can be bigger than the second gate valve 604, as illustrated in FIG. 6.

[0052] In some implementations, a first check valve is installed in the tubing spool inlet of the wellhead. The first check valve can be, e.g., the second check valve 516 of FIG. 5. The tubing spool inlet can be, e.g., the tubing spool inlet 508 of FIG. 5. The wellhead can be, e.g., the wellhead 116 of FIGS. 1A-3B and 6.

[0053] In some implementations, a second check valve is installed in the first portion of the adaptor flange. The second check valve can be, e.g., the first check valve 424 of FIGS. 4C and 5.Implementations

[0054] Certain aspects of the subject matter described here can be implemented as an adaptor flange. The adaptor flange includes a body defining a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening. The body includes a neck portion connecting the first portion to the second portion. An inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion.

[0055] An aspect combinable with any other aspect includes the following features. The adaptor flange includes a single, unitary structure.

[0056] An aspect combinable with any other aspect includes the following features. The outer dimension of the first portion is a maximum distance between two opposite outer edges of the first portion, and the outer dimension of the second portion is a maximum distance between two opposite outer edges of the second portion.

[0057] An aspect combinable with any other aspect includes the following features. Each of the first portion and the second portion has a circular shape. The outer dimension of the first portion is an outer diameter of the first portion, and the outer dimension of the second portion is an outer diameter of the second portion.

[0058] An aspect combinable with any other aspect includes the following features. The first portion of the adaptor flange defines a plurality of first holes evenly spaced in a first circle. The second portion of the adaptor flange defines a plurality of second holes evenly spaced in a second circle. A diameter of the first circle is greater than a diameter of the second circle.

[0059] An aspect combinable with any other aspect includes the following features. The first holes are configured to receive first bolts that couple the adaptor flange to a gate valve configured to be fluidically coupled to a chemical reservoir.

[0060] An aspect combinable with any other aspect includes the following features. The second holes are configured to receive second bolts that couple the adaptor flange to a tubing spool inlet of a wellhead installed at a surface of a wellbore formed through a subterranean zone.

[0061] An aspect combinable with any other aspect includes the following features. The VR plug profile is configured to receive a VR plug or a check valve.

[0062] Certain aspects of the subject matter described here can be implemented as a wellbore chemical injection assembly. The wellbore chemical injection assembly includes a body defining a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening. The body includes a neck portion connecting the first portion to the second portion. An inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion. The wellbore chemical injection assembly includes a check valve that includes an exterior plug profile that engages with the VR plug profile of the adaptor flange.

[0063] An aspect combinable with any other aspect includes the following features. The outer dimension of the first portion is a maximum distance between two opposite outer edges of the first portion, and the outer dimension of the second portion is a maximum distance between two opposite outer edges of the second portion.

[0064] An aspect combinable with any other aspect includes the following features. Each of the first portion and the second portion has a circular shape. The outer dimension of the first portion is an outer diameter of the first portion, and the outer dimension of the second portion is an outer diameter of the second portion.

[0065] An aspect combinable with any other aspect includes the following features. The check valve is configured to be removably installed within the adaptor flange.

[0066] An aspect combinable with any other aspect includes the following features. The first portion of the adaptor flange defines a plurality of first holes evenly spaced in a first circle. The second portion of the adaptor flange defines a plurality of second holes evenly spaced in a second circle. A diameter of the first circle is greater than a diameter of the second circle.

[0067] Certain aspects of the subject matter described here can be implemented as a method. The method includes providing an adaptor flange including a body defining a through opening. The body includes a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening. The first portion includes a valve removal (VR) plug profile. The body includes a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening. The body includes a neck portion connecting the first portion to the second portion. An inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion. An outer dimension of the first portion is greater than an outer dimension of the second portion. The method includes coupling the first portion of the adaptor flange to a first gate valve configured to be fluidically coupled to a chemical reservoir; coupling the second portion of the adaptor flange to a tubing spool inlet of a wellhead installed at a surface of a wellbore formed through a subterranean zone; and injecting chemicals through the first gate valve and the adaptor flange into the tubing spool inlet.

[0068] An aspect combinable with any other aspect includes the following features. Coupling the second portion of the adaptor flange to the tubing spool inlet of the wellhead includes: coupling the second portion of the adaptor flange to a second gate valve; and coupling the second gate valve to the tubing spool inlet of the wellhead.

[0069] An aspect combinable with any other aspect includes the following features. A first check valve is installed in the tubing spool inlet of the wellhead.

[0070] An aspect combinable with any other aspect includes the following features. A second check valve is installed in the adaptor flange.

[0071] An aspect combinable with any other aspect includes the following features. A first VR plug is installed in the tubing spool inlet of the wellhead.

[0072] An aspect combinable with any other aspect includes the following features. An inflow test is performed to assess effectiveness of isolation provided by the first VR plug.

[0073] An aspect combinable with any other aspect includes the following features. A second VR plug is installed in the adaptor flange.

[0074] Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. Moreover, aspects described with reference to any figure or any implementation can be combined with aspects described with any other figure or any other implementation.

[0075] It is understood that the articles “a,”“an,” and “the” in this disclosure are intended to mean that there are one or more of the elements in the preceding descriptions. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one example” or “an example” of the present disclosure are not intended to be interpreted as excluding the existence of additional examples that also incorporate the recited features. For example, any element described in relation to an example herein may be combinable with any element of any other example described herein. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about” or “approximately” the stated value, as would be appreciated by one of ordinary skill in the art encompassed by examples of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable manufacturing or production process, and may include values that are within 5%, within 1%, within 0.1%, or within 0.01% of a stated value.

[0076] A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made to examples disclosed herein without departing from the spirit and scope of the present disclosure. Equivalent constructions, including functional “means-plus-function” clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words ‘means for’ appear together with an associated function. Each addition, deletion, and modification to the examples that falls within the meaning and scope of the claims is to be embraced by the claims.

[0077] The terms “approximately,”“about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,”“about,” and “substantially” may refer to an amount that is within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount. Further, it should be understood that any directions or reference frames in the preceding description are merely relative directions or movements. For example, any references to “up” and “down” or “above” or “below” are merely descriptive of the relative position or movement of the related elements.

Examples

Embodiment Construction

[0017]Hydrocarbons entrapped in subsurface reservoirs flow from the reservoirs through the subterranean zone into the wellbore formed in the subterranean zone. Wellbore equipment are installed within the wellbore to produce the hydrocarbons to the surface. The fluids, e.g., high saline formation brines, various mixtures of oil and mixtures of gas (such as natural gas, hydrogen sulfide, carbon dioxide) that flow into the wellbore through the subterranean zone are extremely corrosive. The wellbore equipment, e.g., tubulars, packers, and the like, can be adversely impacted by the long-term contact with such fluids. For example, the equipment can corrode, or scales or sludges can build up on the equipment or both. The adverse impact on the wellbore equipment, in turn, can impact well production, well integrity, surface production facilities and the like. The adverse impact of the wellbore fluids can be reduced by flowing (i.e., injecting or pumping) chemical inhibitors into the wellbore...

Claims

1. A wellbore chemical injection assembly, comprising:an adaptor flange comprising a body defining a through opening, the body comprising:a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening, the first portion comprising a valve removal (VR) plug profile;a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening; anda neck portion connecting the first portion to the second portion, wherein an inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion,wherein an outer dimension of the first portion is greater than an outer dimension of the second portion; anda VR plug configured to be installed in the adaptor flange such that, together with the adaptor flange, the VR plug serves, with the VR plug engaged with the VR plug profile, as a fluid barrier that allows removing a valve from the first portion of the adaptor flange,wherein the first portion of the adaptor flange defines a plurality of first holes evenly spaced in a first circle, the second portion of the adaptor flange defines a plurality of second holes evenly spaced in a second circle, and wherein a diameter of the first circle is greater than a diameter of the second circle.

2. The adaptor flange of claim 1, wherein the adaptor flange comprises a single, unitary structure.

3. The adaptor flange of claim 1, wherein the outer dimension of the first portion is a maximum distance between two opposite outer edges of the first portion, and the outer dimension of the second portion is a maximum distance between two opposite outer edges of the second portion.

4. The adaptor flange of claim 3, wherein each of the first portion and the second portion has a circular shape, and wherein the outer dimension of the first portion is an outer diameter of the first portion, and the outer dimension of the second portion is an outer diameter of the second portion.

5. (canceled)6. The adaptor flange of claim 5, wherein the first holes are configured to receive first bolts that couple the adaptor flange to a gate valve configured to be fluidically coupled to a chemical reservoir.

7. The adaptor flange of claim 5, wherein the second holes are configured to receive second bolts that couple the adaptor flange to a tubing spool inlet of a wellhead installed at a surface of a wellbore formed through a subterranean zone.

8. The adaptor flange of claim 1, wherein the VR plug profile is configured to receive the VR plug.

9. A wellbore chemical injection assembly, comprising:an adaptor flange comprising a body defining a through opening, the body comprising:a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening, the first portion comprising a valve removal (VR) plug profile;a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening; anda neck portion that connects the first portion to the second portion, wherein an inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion,wherein an outer dimension of the first portion is greater than an outer dimension of the second portion; anda check valve configured to be installed in the adaptor flange and comprising an exterior plug profile that engages with the VR plug profile of the adaptor flange, wherein the VR plug profile is based on an American Petroleum Institute (API) standard.

10. The wellbore chemical injection assembly of claim 9, wherein the outer dimension of the first portion is a maximum distance between two opposite outer edges of the first portion, and the outer dimension of the second portion is a maximum distance between two opposite outer edges of the second portion.

11. The wellbore chemical injection assembly of claim 10, wherein each of the first portion and the second portion has a circular shape, and wherein the outer dimension of the first portion is an outer diameter of the first portion, and the outer dimension of the second portion is an outer diameter of the second portion.

12. The wellbore chemical injection assembly of claim 9, wherein the check valve is configured to be removably installed within the adaptor flange.

13. The wellbore chemical injection assembly of claim 9, wherein the first portion of the adaptor flange defines a plurality of first holes evenly spaced in a first circle, the second portion of the adaptor flange defines a plurality of second holes evenly spaced in a second circle, and wherein a diameter of the first circle is greater than a diameter of the second circle.

14. A method, comprising:providing an adaptor flange comprising a body defining a through opening, the body comprising:a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening, the first portion comprising a valve removal (VR) plug profile;a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening; anda neck portion that connects the first portion to the second portion, wherein an inner diameter transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion,wherein an outer dimension of the first portion is greater than an outer dimension of the second portion;coupling the first portion of the adaptor flange to a first gate valve configured to be fluidically coupled to a chemical reservoir;coupling the second portion of the adaptor flange to a tubing spool inlet of a wellhead installed at a surface of a wellbore formed through a subterranean zone;injecting chemicals through the first gate valve and the adaptor flange into the tubing spool inlet;installing a first check valve in the tubing spool inlet of the wellhead; andinstalling a second check valve in the adaptor flange.

15. The method of claim 14, wherein coupling the second portion of the adaptor flange to the tubing spool inlet of the wellhead comprises:coupling the second portion of the adaptor flange to a second gate valve; andcoupling the second gate valve to the tubing spool inlet of the wellhead.

16. (canceled)17. (canceled)18. (canceled)19. The method of claim 14, comprising:removing the first check valve from the tubing spool inlet of the wellhead;installing a first VR plug in the tubing spool inlet of the wellhead; andperforming an inflow test to assess effectiveness of isolation provided by the first VR plug.

20. (canceled)21. The wellbore chemical injection assembly of claim 1, further comprising a gate valve coupled with the first portion of the adaptor flange such that, with the VR plug detached from the adaptor flange, the adaptor flange allows a fluid to be injected through the gate valve and the adaptor flange, into a wellhead coupled with the adaptor flange.

22. The wellbore chemical injection assembly of claim 9, wherein the check valve is configured to be installed in the adaptor flange such that, together with the adaptor flange, the check valve serves, with the check valve coupled with the adaptor flange profile, as a fluid barrier that allows removing a valve from the first portion of the adaptor flange.

23. The wellbore chemical injection assembly of claim 22, further comprising a gate valve coupled with the first portion of the adaptor flange such that, with the check valve detached from the adaptor flange, the adaptor flange allows a fluid to be injected through the gate valve and the adaptor flange, into a wellhead coupled with the adaptor flange.

24. An adaptor flange, comprising:a body defining a through opening, the body comprising:a first portion terminating at a first end of the adaptor flange and defining a first inner diameter of the through opening, the first portion comprising a valve removal (VR) plug profile adapted to receive a VR plug such that, together with VR plug, the adaptor flange serves, with the VR plug engaged with the VR plug profile, as a fluid barrier that allows at least one of (i) attaching a valve to the first portion of the adaptor flange, or (ii) removing a valve from the first portion of the adaptor flange;a second portion terminating at a second end of the adaptor flange and defining a second inner diameter of the through opening smaller than the first inner diameter of the through opening; anda neck portion connecting the first portion to the second portion, wherein an inner diameter of the through opening transitions from the first inner diameter to the second inner diameter along a longitudinal length of the neck portion,wherein an outer dimension of the first portion is greater than an outer dimension of the second portion.

25. The adaptor flange of claim 24, wherein the first portion is coupled with a gate valve such that, with the VR plug detached from the adaptor flange, the body allows a fluid to be injected through the gate valve and the body, into a wellhead coupled with the body.

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