Wellbore Chemical Injection with an Adaptor Flange

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

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.

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

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.

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.

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.

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.

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.

and IC are examples of different arrangements to inject chemicals into a wellboreusing the adaptor flangedescribed 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.shows a schematic arrangement of using the adaptor flangeto inject chemicals into a downhole location in the wellborefor flow in an uphole direction through a production tubingto the surface. The wellboreis formed in a subterranean zone. The wellborecan be cased and cementedor can be non-cement cased or partially cased. Perforationsformed in the wellbore wall allow hydrocarbons to flow from the subterranean zoneinto the wellbore. Packerscan be installed near a downhole end of the production tubingto isolate a region of the wellborebelow the packersfrom a region above the packers. The hydrocarbons flow from the subterranean zonein an uphole direction (arrows) towards a downhole inlet of the production tubingand towards the surface of the wellbore.

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

shows another schematic arrangement of using the adaptor flangeto inject chemicals into a downhole location in the wellborefor flow in an uphole direction through a production tubingto the surface. The arrangement ofis substantially identical to that of, except that the arrangement ofdoes not implement the packers(). The arrangement ofallows monitoring annulus pressure behind the production tubing, which helps to monitor liquid loading condition of the wellbore.shows another schematic arrangement of using the adaptor flangeto inject chemicals into a downhole location in the wellborefor flow in an uphole direction through a production tubingto the surface. The arrangement ofis substantially identical to that of, except that the arrangement ofdoes not implement the control lineand does not implement packers. Instead, the chemicals are injected from the surface, through the tubing spool, directly into the annulus. The chemicals will travel downhole through the annulus and enter the production tubingwith the hydrocarbons. The wellbore chemical injection adaptor flangecan be used to inject chemicals in any of the arrangements shown inor other arrangements in which wellbore equipment installed within a wellbore needs to be treated with chemicals injected from the surface.

shows a schematic diagram of a wellbore chemical injection systemdisposed at a surface of the wellbore. The systemis shown as being implemented with the wellboredescribed with reference to. However, the systemis useable with any of the arrangements shown inand IC or other arrangements in which wellbore equipment need chemical treatment. The systemincludes a chemical reservoir(e.g., a tank) that stores the chemical or chemicals to be injected into the wellbore. A chemical line(e.g., tubing or pipe) fluidically couples the reservoirto the adaptor flange. Flow through the chemical lineis implemented using a pump(e.g., a high pressure pump) and flow control equipment (e.g., control valves) fluidically coupled along the length of the chemical line. One or more of the control valves (e.g., control valves) can be installed near and fluidically coupled to the wellbore chemical injection adaptor flange. The adaptor flangeis fluidically coupled to an inlet of the tubing spoolof the wellhead.

The adaptor flangeand 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.

is a schematic diagram of a wellheadincluding a tubing spoolto which an example implementation of a wellbore chemical injection system is connected. The wellheadcan be attached to different types of tubings installed within the wellbore, e.g., a surface casing, an intermediate casing, the production tubing. The wellheadcan include multiple spools including a top tubing spool, a first casing spooland a second casing spool. Each spool can be fluidically coupled to one of the tubings or casing installed within the wellbore. The top tubing spoolcan be fluidically coupled to the production tubing. Each spool can be fluidically coupled to respective gate valves, e.g., gate valvesfluidically coupled to the top tubing spool, gate valvesfluidically coupled to the first casing spool, gate valvesfluidically coupled to the second casing spool. 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 treeis installed above the top tubing spooland can be fluidically coupled to the top tubing spoolthrough a gate valve.

In some implementations, the adaptor flangecan be fluidically coupled to the top tubing spoolbetween the gate valveand an inlet to the tubing spool. In alternative implementations, the adaptor flangecan be fluidically coupled between the gate valvesandas described with further details below in, or the gate valvesandcan be fluidically coupled between the adaptor flangeand the tubing spool inlet.is a schematic diagram of flowing chemicals through the wellbore chemical injection assembly of. Using the wellbore chemical injection system(), chemicals from the chemical reservoir() are flowed through the chemical line() into the inlet of the tubing spooland into the annulus between the production tubingand the inner wall of the intermediate casing, as schematically shown by the arrow.

illustrate a cross-section view of the example adaptor flangeimplemented in.illustrates side views of two ends of the example adaptor flange. For ease of description, reference will be made to bothwhen describing the structure of the adaptor flange. As shown in, the adaptor flangeincludes a body. The bodydefines a through opening. The bodyincludes a first portion, a second portionthat is opposite the first portion, and a neck portionconnecting the first portionto the second portion. The first portionterminates at a first endof the adaptor flange. The second portionterminates at a second endof the adaptor flange. The second endis opposite the first endalong a longitudinal direction of the through opening, e.g., x-direction.

The through openinghas varying inner diameters. The first portiondefines a first inner diameterof the through opening. The second portiondefines a second inner diameterof the through opening. The second inner diameteris smaller than the first inner diameterof the through opening. In the neck portion, the inner diameter of the through openingtransitions from the first inner diameterto the second Inner diameteralong a longitudinal length of the neck portion, e.g., x-direction.

The first portionincludes an interior valve removal (VR) plug profileto receive a solid VR plug or a check valve type VR plug. The VR plug profilecan be defined by the American Petroleum Institute (API) SPEC 6A standard. The VR plug profilecan be configured to accommodate for the installation of a VR plug or a threaded check valve. VR plugs, e.g., VR plugas illustrated inbelow, 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 valvesas illustrated inbelow, can reduce contamination, damage or safety hazards from reverse flows, as described with further details below in.

An outer dimensionof the first portionis greater than an outer dimensionof the second portion. In some implementations, the outer dimensionof the first portionis a maximum distance between two opposite outer edges of the first portion. Similarly, the outer dimensionof the second portionis a maximum distance between two opposite outer edges of the second portion. For example, as illustrated in, the first portionand the second portioncan have a circular cross-section shape. The outer dimensionof the first portioncan be its outer diameter, which is greater than an outer diameterof the second portion. In some implementations, the first portionand the second portionhave a rectangular cross-section shape (not shown). The outer diameter can be the length or the width of the rectangle.

In some implementations, as illustrated in, the first portiondefines first holeswhich are evenly spaced in a first circlearound the perimeter to align with corresponding holes on the mating flange or component. Likewise, the second portiondefines second holesevenly spaced in a second circleThe holescan be configured to receive bolts. The circlecan pass through the centers of the holes, as shown in. In some implementations, the first circlehas a greater diameter than that of the second circle

In some implementations, the first holesare configured to receive first bolts that couples the adaptor flangeto a gate valve configured to be fluidically coupled to a chemical reservoir(). With greater outer diameterand/or greater circle diameter, the first portioncan be fluidically coupled to a larger gate valve, e.g., the gate valve. 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, two VR plugs or check valves can be installed: one is in the tubing spool inletof the wellhead, and the other one is in the adaptor flange. 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 wellheadand adapter flangemay 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 profileis damaged due to various factors such as thread damage, or corrosion.

In some implementations, the second holesare configured to receive second bolts that couples the adaptor flangeto the tubing spool inlet of the wellheadinstalled at a surface of the wellboreformed through a subterranean zone. In some implementations, the first portionand the second portionalso have groovesto match with tongues in the mating components.

In some implementations, the adaptor flangeis a single, unitary structure. In some implementations, the adaptor flangeis an assembled structure by attaching the first portion, the second portionand the neck portiontogether via methods, including without limitation to, gluing, bolting, screwing, riveting or welding. The adaptor flangecan be made from materials such as carbon steel, stainless steel, alloy steel, or other materials suitable for the wellheadoperations.

illustrates a schematic view of an example wellbore chemical injection assembly. The wellbore chemical injection assemblyincludes the adaptor flangeof. The wellbore chemical injection assemblyalso includes a threaded check valvewith an exterior plug profile that engages with the VR plug profileof the adaptor flange. The exterior plug profile of the check valvecan be metal threads that matches with the VR plug profile. 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 valvecan direct the chemicals from the chemical reservoir() to the wellhead(), while preventing reverse formation fluid flow from downhole wellboreto the first gate valve. 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.

In some implementations, the threaded check valveis removably installed within the adaptor flangeby coupling or decoupling its exterior plug profile with the VR plug profileof the adaptor flange. 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. The same adaptor flange can be used repeatedly for multiple installations of check valves, contributing to cost savings and resource efficiency.

In some implementations, the first portionof the adaptor flangeis coupled to a first gate valve. The first gate valvecan be implemented as the gate valvein. As described with further details below in, the first gate valvecan be configured to fluidically couple to a chemical reservoir() from which chemical is injected through the first gate valveand the adaptor flangeinto the tubing spool inlet. In some implementations, the pressure rating for the adaptor flangeis the same as the first gate valve. The pressure rating can indicate the maximum pressure at which valves can safely operate without risk of failure. In some implementations, the first gate valveand the adaptor flangehave the same pressure ratings ranging from 1000 pounds per square inch (psi) (6.9e6 Pascal) to 10000 psi (6.9e7 Pascal).

illustrates a schematic view of the adaptor flangewith a VR plug. The VR plugcan be installed by engaging with the VR plug profile. The VR plugcan 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 plugis 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.

illustrates a schematic diagram of a tubing spooland the example wellbore chemical injection assemblyof. As illustrated, the tubing spoolhas a main bodywith a cylindrical or rectangular structure. The main bodycan be made of forged steel or cast steel. The tubing spoolcan also include a tubing hangerwhich supports the tubing strings and provides a seal between the tubing stringsand the spool. The tubing stringscan be the surface casing, the intermediate casing, and/or the production tubingin. The tubing spoolhave inletsor outlets on side walls of the main body, where the adaptor flangeor the gate valvescan be attached to provide access points for auxiliary lines or equipment, such as chemical injection lines. The chemicals can be injected into the tubing spoolthrough the inlets, e.g., the tubing spool inlet.

In some implementations, the side inletsof the tubing spoolcan include a second VR plug profile. The second VR plug profilecan be configured to receive a second VR plug (not shown) or a second check valve(also called inlet check valvein this disclosure). In some implementations, all two VR plug profiles,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,can have exterior plug profiles that engages with the respective VR plug profiles,for removable installation and retrieval. The exterior plug profiles can be metal threads. In some situations, the check valves,can be installed and kept in the wellheadduring operation to direct the chemical along only one direction.

The adapter flangecan be deployed when the wellhead VR profile is damaged due to, e.g., corrosion, or thread damages. Installing the adapter flangewith VR profile between wellhead and the first gate valvecan provide an internal isolation on the wellhead side outlet port within the system. The check valves,can be deployed as two internal fail-stop barriers. As noted above, the check valves,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 reservoirto the wellhead(), the check valveremains open, allowing the fluid to pass through. However, if there is backflow or flow in the opposite direction, e.g., from the wellheadto the chemical reservoir(), 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,installed inside the adaptor flangeand the tubing spoolare 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.

illustrates a schematic view of the example adaptor flangeimplemented between two gate valves. As illustrated, the first portionof the adaptor flangecan be fluidically coupled to the first gate valve. The second portionof the adaptor flangecan be fluidically coupled to a second gate valve. The second gate valvecan be fluidically coupled to the tubing spool inletof a wellheadinstalled at a surface of a wellboreformed through a subterranean zone. The tubing spool inletcan include the inlet check valve(). The first gate valvecan be fluidically coupled to a chemical reservoir() from which chemical is injected through the first gate valve, the adaptor flangeand the second gate valveinto the tubing spool inlet.

As noted above, as the first portionof the adaptor flangehas a greater outer diameter() than that of the second portion, the first portionof the adaptor flangecan be coupled to a larger gate valve. Therefore, the first gate valvecan have a larger size than the second gate valve, as illustrated in. Larger valves can allow high chemical flow rates or large volumes of chemical fluid, enhancing chemical injection efficiency.

also illustrates a chemical flow direction (arrow) through the adaptor flange. Using the wellbore chemical injection assembly(), chemicals from the chemical reservoir() are flowed through the chemical line() into the first gate valve, the first check valveof the adaptor flange, the second gate valve, and the inletof the tubing spool, and into the annulus between the production tubingand the inner wall of the intermediate casing, as schematically shown by the arrow.

illustrates an example processto inject chemicals through a tubing spool side adaptor flange. At step, an adaptor flange is provided. The adaptor flange can be, e.g., any one of the adaptor flangeof. As illustrated in, the adaptor flangeincludes a bodyand the bodydefines a through opening. The bodyincludes a first portion, a second portionopposite the second portion, and a neck portionconnecting the first portionto the second portion. The through openinghas a greater inner diameterat the first portioncompared to the inner diameterat the second portion. In the neck portion, the inner diameter of the through openingtransitions from the first inner diameterto the second inner diameteralong a longitudinal length of the neck portion. The first portionincludes a valve removal (VR) plug profileto receive a check valve, e.g., the first check valve, or a VR plug. An outer dimensionof the first portionis greater than an outer dimensionof the second portion.

At step, the first portionof the adaptor flangeis fluidically coupled to a first gate valve, as illustrated in. The first gate valveis configured to be fluidically coupled to a chemical reservoir().

At step, the second portionof the adaptor flangeis fluidically coupled to a tubing spool inletof a wellheadinstalled at a surface of a wellboreformed through a subterranean zone, as illustrated in.

At step, chemicals are injected through the first gate valveand the adaptor flangeinto the tubing spool inlet.

At step, in some implementations, a first VR plug is installed in the tubing spool inletof the wellhead, 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, needs be replaced, the first VR plug may be installed in the tubing spool inletof the wellheadfor 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.

At step, in some implementations, a second VR plug is installed in the adaptor flange, 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 plugof.

In some implementations, coupling the second portionof the adaptor flangeto the tubing spool inletof the wellheadincludes coupling the second portionof the adaptor flangeto a second gate valve() and coupling the second gate valveto the tubing spool inletof the wellhead. The first gate valvecan be bigger than the second gate valve, as illustrated in.

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 valveof. The tubing spool inlet can be, e.g., the tubing spool inletof. The wellhead can be, e.g., the wellheadof.

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 valveof.

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.

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

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.

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.

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.

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.

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.

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.