FIELD OF THE DISCLOSURE
This disclosure relates to pipe connection assemblies. Exemplary deployments of the pipe connection assemblies described in this disclosure are in the subterranean drilling field, and include assemblies for connecting concatenated lengths of riser pipe deployed above ground in lubricator assemblies for subterranean wireline operations. More specifically, the disclosure describes embodiments of a corrosion resistant pipe connection system whose design is characterized to address and remediate corrosion in the connection assembly, such as is typically caused by the harsh corrosive environments often encountered by lubricator assemblies in wireline operations. Embodiments of the disclosed corrosion resistant pipe connection system are also designed to provide galvanic protection to the connection assemblies and other wellhead tools positioned above ground in a wellhead toolstring.
BACKGROUND
FIG. 1A illustrates, for orientation purposes, a conventional wellhead tool string 100 that might typically be deployed above ground during wireline operations in subterranean drilling. Exemplary deployments of the pipe connection assemblies described in this disclosure may be found in lubricator assemblies located in the region of lubricators 25 as shown on tool string 100 on FIG. 1A. FIG. 1A illustrates an example of such a prior art pipe connection deployment, showing prior art union assembly 220 positioned in the region of lubricators 25. For orientation, tool string 100 on FIG. 1A shows, from the top towards the bottom (wellhead): dual pack off 10, grease head 10 and line cutter 20 above lubricators 25, and tool trap 30, quick test sub 35, wireline valves 40, plug valve 45, pump in sub 50 and flange assembly 55 below lubricators 25.
Lubricator assemblies located in the region of lubricators 25 on FIG. 1A conventionally include concatenated lengths of riser pipe connected by union assemblies. The lengths of riser pipes are commonly between 5 feet and 10 feet long, although other lengths are conventionally available and used. The lengths of riser pipe typically present male threads at both ends.
FIGS. 2A, 2B and 2C illustrate a conventional union assembly 220 as shown on FIG. 1A enabling a connection (coupling) between lengths of conventional riser pipe 200 as might typically be deployed in the region of lubricators 25 on FIG. 1A. First and second riser pipes 200 on FIGS. 2A, 2B and 2C each provide male riser pipe threads 201. Union assembly 220 on FIGS. 2A, 2B and 2C includes female union and male union 226, 228 each with corresponding internal female threads 221F, 221M for enabling a threaded connection with male riser pipe threads 201 on riser pipes 200 for riser pipe 221F, 221M. Female union and male union 226, 228 each further advantageously provide corresponding female union and male union tightening recesses 235, 233 to receive operator tools to assist with conjoining male riser pipe threads 201 and union internal female threads 221F, 221M. FIGS. 2A, 2B and 2C show that the connection of union assembly 220 involves initially placing nut 222 over first riser pipe 200 before male union 228 is threaded onto first riser pipe 200. FIG. 2C depicts retaining nut 231 advantageously provided on the exterior of male union 228 to prevent nut 222 from sliding off male union 228 once first riser pipe 200, nut 222, and male union 228 are assembled as shown. Then, as shown on FIGS. 2A, 2B and 2C, when female union 226 is threaded onto second riser pipe 200, nut 222 may be tightened over female union 226 by conjoining nut threads 224 and female union threads (for nut) 227. Nut 222 advantageously provides nut tightening recesses 234 to receive operator tools to assist with conjoining nut threads 224 and female union threads (for nut) 227. As further shown on FIG. 2C, o-rings 232 (one on female union 226 and two on male union 228) provide seals within union assembly 220. A first o-ring 232 seals male union 228 and first riser pipe 200; a second o-ring 232 seals female union 226 and male union 228, and a third o-ring 232 seals female union 226 and second riser pipe 200.
Corrosion of tools and piping is endemic to and persistent in many wellhead services. Fluids pumped and drawn through metal tool strings, fittings and piping can be inherently corrosive, especially in fracking operations. Further, environmental regulations over recent years have required increasingly that subterranean operations such as fracking use recycled water rather than a constant flow of new, fresh water. Repeated recycling increases the concentration of dissolved salts whose free ions tend to increase the potential for corrosion in tool strings, fittings and piping carrying the recycled water.
Embodiments of prior art union assembly 220 as shown on FIGS. 2A, 2B and 2C have known corrosion characteristics. Embodiments of riser pipes 200 on FIGS. 2A, 2B and 2C may be made from 28 Chrome (also known as Alloy 28). In fact, the use of 28 Chrome for riser pipes 200 is quite common and popular in oilfield deployments such as fracking where the internal fluid may be particularly corrosive to metals. 28 Chrome exhibits a high resistance to pitting and crevice corrosion, particularly in the presence of chlorides as may be common in subterranean drilling operations. 28 Chrome (UNS N08028) is a cold hardened nickel-based alloy intended for corrosion resistance in highly sour (H2S) environments with moderate chloride content. 28 Chrome also exhibits high strength up to temperatures up to 350° F. 28 Chrome offers increased resistance to the effects of H2S as compared to stainless steels, for example, suggesting use of 28 Chrome in downhole tubular components such as packers and lubricators.
Embodiments of female and male unions 226, 228 on FIGS. 2A, 2B and 2C may be made from L80 or P110. Embodiments of nut 222 on FIGS. 2A, 2B and 2C may also be made from L80 or P110. L80 and P110 are similar low-alloy steels commonly used in oil and gas drilling applications. L80 is heat-treated differently from P110 in order to achieve a higher yield strength. Similar to 28 Chrome, both L80 and P110 are high-strength materials with excellent toughness, fatigue strength, and wear resistance properties, which makes them suitable for use in harsh operating conditions. However, L80 and P110 are API-approved grades of steels having a lower corrosion resistance in subterranean drilling applications than, say, 28 Chrome.
Pitting corrosion is a first known corrosion characteristic in embodiments of union assembly 220 as shown on FIGS. 2A, 2B and 2C. FIG. 2A identifies pitting corrosion as may be seen, for example, in male union interior 225 and 223 and on other components that may be made from L80 or P110. As noted above, L80 or P110 is less resistant to pitting corrosion than 28 Chrome in a highly corrosive fracking fluid service.
Crevice corrosion is a second known corrosion characteristic in embodiments of union assembly 220 as shown on FIGS. 2A, 2B and 2C. FIG. 2A identifies crevice corrosion as “localized corrosion due to narrow openings”. Referring also to FIG. 2C, crevice corrosion may be seen, for example, in the threaded connection 224, 227 between nut 222 and female union 226, where both components may be made from L80 or P110. It is well known that threads and other narrow pathways (“crevices”) formed in metal surfaces have a heightened susceptibility to corrosion because of the increased surface area to volume ratio inherent to the pathways.
Galvanic corrosion (or “bimetallic corrosion”) is a third known corrosion characteristic in embodiments of union assembly 220 as shown on FIGS. 2A, 2B and 2C. FIG. 2A identifies galvanic corrosion as “localized preferential corrosion in the presence of corrosive media”. Galvanic corrosion may be seen on FIGS. 2A, 2B and 2C, for example, where the shoulder end of one riser pipe 200 abuts male union 228 and the shoulder end of the other riser pipe 200 abuts female union 226 once union assembly 220 is fully assembled. As noted above, embodiments of female union 226 may be made from L80 or P110 and embodiments of riser pipe 200 may be made from 28 Chrome. These are dissimilar metals. When union assembly 220 is fully assembled and in fracking service, the fracking fluid may act as an electrolyte. It is well known that galvanic corrosion may arise when dissimilar metals are in electrical contact and also immersed in an electrolyte. One of the dissimilar metals acts as a less “noble” metal and becomes sacrificial in an electrolytic current flowing through the electrolyte. In the case of FIGS. 2A, 2B and 2C, the L80 or P110 components may become sacrificial and corrode.
There is therefore a need in the art for an improved corrosion resistant system for connecting (concatenating) riser pipes where the design of the system is optimized to reduce corrosion. Ideally, the optimized design will address some, and preferably all, of the corrosion characteristics identified above, namely pitting corrosion, crevice corrosion and galvanic corrosion.
SUMMARY AND TECHNICAL ADVANTAGES
These and other needs in the prior art are addressed by improved designs of corrosion resistant systems, embodiments of which systems are disclosed herein with reference to FIGS. 1B and 3 through 5B. Embodiments of improved connection assembly designs are intended to substitute for and replace conventional union assembly 220 shown on FIGS. 2A, 2B and 2C, advantageously without any modification of riser pipes 200.
Reference is now made to FIG. 1B. FIG. 1B illustrates, for orientation purposes, a wellhead toolstring 110. Wellhead toolstring 110 on FIG. 1B is similar to the lower portion of conventional tool string 100 of FIG. 1A, except with conventional union assembly 220 removed and replaced with corrosion resistant connection assemblies 300, anode assembly 400, upper anode assembly UA and isolator assembly 500. Corrosion resistant connection assemblies 300 may also be referred to herein as “connection assemblies 300”. Deployment of improved corrosion resistant connection assemblies 300 remediates corrosion significantly in pipe connections in riser pipe strings such as near lubricators on a wireline wellhead tool string. Embodiments of corrosion assemblies are described below with reference to FIGS. 3, 3A and 3B. Generally speaking, though, improved corrosion resistant connection assemblies 300 include male and female unions threaded on to riser pipes 200 and configured to retain an o-ring housing positioned between the male and female unions. A nut is placed over the male and female unions to retain and secure the connection assembly. The action of connection assemblies 300 to remediate pipe connection corrosion is discussed further below in this disclosure. Different embodiments of the disclosed connection assembly 300 may include further features to enhance various aspects of the design (such aspects including, for example, ease of assembly and disassembly of the connection assembly in field conditions).
As noted, connection assemblies 300 on FIG. 1B remediate corrosion in pipe connections such as located in the wellhead toolstring region around lubricators. The nature of endemic and persistent corrosion, however, is that the potential for corrosion (and especially galvanic corrosion) now increases in the neighboring regions around the lubricators region where corrosion has been actively remediated. Wellhead tools and fittings in such neighboring regions may be considered vulnerable to an increased potential for galvanic corrosion. Embodiments of the improved corrosion resistant system disclosed herein therefore provide a cathodic protection system (also referred to herein as a “galvanic protection system”) characterized to address the increased potential for corrosion in vulnerable neighboring tools and fittings. As is well understood, cathodic protection is a technique used to control the corrosion of a metal surface by making it the cathodic side of an electrochemical cell. The metal to be protected (in this case, as found in vulnerable wellhead tools and fittings such as riser pipe connection assemblies) is connected with another sacrificial metal to act as the anode of the electrochemical cell. The sacrificial metal on the anode side is selected to be less “noble” (that is, more anodic) than the metal to be protected, in that the sacrificial metal is more attractive to corrosive cations in the cell than the metal to be protected.
FIG. 1B illustrates anode assembly 400 and, in some embodiments, upper anode assembly UA, either side of connection assemblies 300 to provide galvanic protection in wellhead toolstring 110. Anode assembly 400 and upper anode assembly UA may also be referred to as “first and second anode assemblies” respectively in embodiments where upper anode assembly UA is provided. Embodiments of anode assembly 400 are described in more detail below with reference to FIGS. 4, 4A and 4B. Anode assembly 400 and upper anode assembly UA are deployed to provide galvanic corrosion protection in neighboring regions above and below lubricators (where connection assemblies 300 are deployed). In this way, anode assembly 400 and upper anode assembly UA may serve to protect vulnerable tools and fittings in these neighboring regions against an increased potential for galvanic corrosion. FIG. 6 is a reference graphic showing various metals on a continuum of “most noble” to “least noble”. As will be described further below, embodiments of the disclosed corrosion resistant system described in this disclosure provide anodes in anode assembly 400 that are made from less noble metals on FIG. 6 so that galvanic corrosion prefers the anodes rather than wellhead tools and fittings. In contrast, components (or surfaces) contacting corrosive fluid in wellhead tools and fittings are made from more noble metals on FIG. 6. Further, in the event there is any residual galvanic corrosion not directed to the anodes in anode assembly 400, components (or surfaces) contacting corrosive fluid in wellhead tools and fittings may be engineered in some embodiments so that galvanic corrosion prefers larger components, such as riser pipes, over smaller and potentially more valuable components, such as wellhead tool and fitting components.
As noted, the galvanic corrosion protection enabled by anode assembly 400 and upper anode assembly UA on FIG. 1B is directed to vulnerable tools and fittings in a specific tool string. In some embodiments, this vulnerable tool string may represent the wireline tool string above ground at a wellhead, although the scope of this disclosure is not limited in this regard. Regardless, wellhead tool strings are typically electrically connected to subterranean drill strings, which may extend for long distances underground. It is therefore advantageous in some embodiments to isolate a vulnerable tool string electrically from, for example, a length of drill string further downhole. In this way, galvanic corrosion protection (such as may be enabled by anode assembly 400 and upper anode assembly UA on FIG. 1B) can be focused on the vulnerable tool string. The potential galvanic protection provided to the vulnerable tool string would likely be diminished absent such electrical isolation. Without such electrical isolation, galvanic protection to the tool string dissipates as the electrochemical cell's voltage drop is forced also to protect a portion of the drill string, for example.
FIG. 1B illustrates isolator assembly 500 below (i.e., downhole from) anode assembly 400 to isolate wellhead toolstring 110 electrically. Embodiments of isolator assembly 500 are described in more detail below with reference to FIGS. 5, 5A and 5B. In embodiments, isolator assembly 500 is disposed to be positioned above ground in wellhead toolstring 110 such that isolator assembly 500 isolates electrically an uphole portion of wellhead toolstring 110 from a downhole portion thereof. Isolator assembly 500 is configured to isolate at least one wellhead tool in wellhead toolstring 110 electrically from the downhole portion of the wellhead toolstring 110 when such wellhead tool in the wellhead toolstring is positioned in the uphole portion of the wellhead toolstring (and preferably positioned between anode assembly 400 and isolator assembly 500).
It is therefore a technical advantage of the disclosed corrosion resistant system technology to provide an internal corrosion management system. As noted above, environmental regulations have required increasingly that subterranean operations such as fracking use recycled water. Repeated recycling increases the concentration of dissolved salts whose free ions tend to increase the potential for corrosion in tool strings, fittings and piping carrying the recycled water. The increasing concentration of the recycled water makes the dissolved salt concentration in the water easier to monitor accurately, allowing the corrosion resistant system to be characterized and controlled to address the expected corrosiveness of the water in a form of feedback loop. The disclosed corrosion resistant system thus uses the increasing corrosiveness of the water against itself to control the corrosiveness.
A further technical advantage of the technology embodied on improved connection assemblies 300 to provide improved resistance to pitting and crevice corrosion. Disclosed embodiments of the technology provide internal fluid flow paths engineered to contact only components whose materials resist known forms of corrosion such as pitting and crevice corrosion. In some embodiments, components contacted by the internal fluid path may be made from 28 Chrome, whose beneficial corrosion resistance characteristics are described above in the Background section. Use of 28 Chrome components also encourages compatibility with 28 Chrome riser pipes when such are present, as is quite common in oilfield deployments such as fracking.
A further technical advantage of the technology embodied on improved connection assemblies 300 is to provide improved resistance to galvanic corrosion. Some disclosed embodiments of the technology provide internal fluid flow paths engineered to contact only components made of the same material. Uniformity of material defeats the propensity for galvanic corrosion caused by use of dissimilar metals in an electrolytic environment. In some of such uniform material embodiments, the internal fluid flow path through the connection assembly contacts the male and female union components, plus the o-ring housing retained by the male and female union. The male and female unions and the o-ring housing may all be made from 28 Chrome. Further, embodiments of the disclosed corrosion resistant system provide an anode assembly in the wellhead tool string whose sacrificial anodes are made from less noble metals. These less noble anodes attract galvanic corrosion, directing the galvanic corrosion away from wellhead tools and fitting made from more noble metals. In cases where more noble components have dissimilar metals, embodiments provide materials selections such that any galvanic corrosion in those components prefers larger components, such as riser pipes, over smaller and potentially more valuable components, such as wellhead tool and fitting components.
A further technical advantage of the disclosed corrosion resistance technology is that, in embodiments, the wellhead toolstring may provide an isolator assembly to isolate an uphole portion of the wellhead toolstring electrically from a downhole portion. Galvanic protection provided by the anode assembly is located in the uphole portion. The isolator assembly thus focuses the galvanic protection in the wellhead tool string by deploying an electrical barrier to any potential galvanic protection that the anode assembly might otherwise seek to provide downhole of the isolator assembly.
A further technical advantage of the technology embodied on improved connection assemblies 300 is to provide a connection assembly design that can be deployed in the field without requiring associated changes or adaptations to existing riser pipes. As noted above, embodiments of the improved design are intended to substitute for and replace conventional union assembly 220 shown on FIGS. 2A, 2B and 2C, advantageously without any modification of riser pipes 200.
A further technical advantage of the technology embodied on improved connection assemblies 300 is that embodiments of the improved design are simple and straightforward enough not to require complex centralized manufacturing. Machining of parts is straightforward enough to be within the capability of local artisan machine shops. Assembly and pressure test of the new connection is configured to be done locally at the rig site if preferred. As a result, upgrade and replacement of existing connection assemblies is streamlined.
A further technical advantage of the technology embodied on improved connection assemblies 300 is to facilitate field connection and disconnection of the connection assembly. In some embodiments, retaining rings (advantageously embodied as snap rings) may be provided on the connection assembly to retain components to facilitate threading and unthreading of the connection assembly together, especially at elevation. Once the components are retained, rotation of a lower riser pipe (with female union and o-ring housing installed) should be all that is required, other than local tightening with a tool, to engage threads on the female union with corresponding threads on a nut proffered by the upper riser pipe (with male union and nut installed). Similarly, retention of the components with retaining rings allows the components to remain together once the connection assembly is disengaged by rotating the lower riser pipe in the opposite direction.
A further technical advantage of the technology embodied on improved connection assemblies 300 is to optimize the mass (weight) of the connection assembly via materials selection. It will be understood that the rigging of riser pipe strings (and their interconnection) in the field requires elevated work. The dead weight of the riser pipes and their connection assemblies affects all aspects of such elevated work. Field operators have migrated in the past from L80 or P110 riser pipes to 28 Chrome riser pipes since 28 Chrome enables a thinner-walled, lighter riser pipe. The selection of 28 Chrome components in embodiments of the disclosed connection technology is consistent with a design goal of optimizing the overall dead weight of a concatenated riser pipe string.
In a first aspect, therefore, embodiments of the disclosed corrosion resistant system comprise: a connection assembly disposed to concatenate a first riser pipe to a second riser pipe above ground in a wellhead toolstring; the connection assembly including an o-ring housing such that the o-ring housing is disposed to be interposed between the first riser pipe and the second riser pipe when the connection assembly concatenates the first riser pipe to the second riser pipe; an anode assembly including at least one sacrificial anode, wherein the at least one sacrificial anode acts as a corrosion inhibitor for at least one wellhead tool in the wellhead toolstring when the anode assembly is also positioned above ground in the wellhead toolstring; wherein the first riser pipe has a first riser internal surface, the o-ring housing has a housing internal surface and the second riser pipe has a second internal surface, wherein the first riser internal surface, the housing internal surface and the second riser internal surface are contiguous when the connection assembly concatenates the first riser pipe to the second riser pipe; wherein the first riser internal surface presents a metal having a pitting resistance equivalent number designated as PREN1; wherein the second riser internal surface presents a metal having a pitting resistance equivalent number designated as PREN2; wherein the housing internal surface presents a metal having a pitting resistance equivalent number designated as PRENH; wherein [PRENH-PREN1] is in a range between about −5 and +∞; and wherein [PRENH-PREN2] is in a range between about −5 and +∞.
In embodiments according to the first aspect, the first riser internal surface presents a metal selected from the group consisting of: (a) 28 Chrome; (b) Inconel 718; (c) L80; and (d) P110.
In embodiments according to the first aspect, the second riser internal surface presents a metal selected from the group consisting of: (a) 28 Chrome; (b) Inconel 718; (c) L80; and (d) P110.
In embodiments according to the first aspect, the housing internal surface presents a metal selected from the group consisting of: (a) 28 Chrome; (b) Inconel 718; (c) L80; and (d) P110.
According to a second aspect, embodiments of the disclosed corrosion resistant system comprise: a connection assembly disposed to concatenate a first riser pipe to a second riser pipe above ground in a wellhead toolstring; the connection assembly including an o-ring housing such that the o-ring housing is disposed to be interposed between the first riser pipe and the second riser pipe when the connection assembly concatenates the first riser pipe to the second riser pipe; an anode assembly including at least one sacrificial anode, wherein the at least one sacrificial anode acts as a corrosion inhibitor for at least one wellhead tool in the wellhead toolstring when the anode assembly is also positioned above ground in the wellhead toolstring; wherein the first riser pipe is made of a metal having a pitting resistance equivalent number designated as PREN1; wherein the second riser pipe is made of a metal having a pitting resistance equivalent number designated as PREN2; wherein the o-ring housing is made of a metal having a pitting resistance equivalent number designated as PRENH; wherein [PRENH-PREN1] is in a range between about −5 and +∞; and wherein [PRENH-PREN2] is in a range between about −5 and +∞.
In embodiments according to the second aspect, the first riser pipe is made of a metal selected from the group consisting of: (a) 28 Chrome; (b) Inconel 718; (c) L80; and (d) P110.
In embodiments according to the second aspect, the second riser pipe is made of a metal selected from the group consisting of: (a) 28 Chrome; (b) Inconel 718; (c) L80; and (d) P110.
In embodiments according to the second aspect, the o-ring housing is made of a metal selected from the group consisting of: (a) 28 Chrome; (b) Inconel 718; (c) L80; and (d) P110.
In embodiments according to the first aspect or the second aspect, at least one sacrificial anode is a zinc-aluminum alloy.
In embodiments according to the first aspect or the second aspect, the connection assembly further includes a male union and a female union, wherein connection of the male union to the female union enables the o-ring housing to be interposed between the first riser pipe and the second riser pipe when the connection assembly concatenates the first riser pipe to the second riser pipe.
In embodiments according to the first aspect or the second aspect, the connection assembly further includes a nut, wherein threading of the nut over the female union enables connection of the male union to the female union.
In embodiments according to the first aspect or the second aspect, the anode assembly is a first anode assembly, and in which the wellhead corrosion resistant system further includes a second anode assembly, wherein the second anode assembly disposed to be positioned also above ground in the wellhead toolstring such that at least one wellhead tool in the wellhead toolstring is interposed between the first anode assembly and the second anode assembly.
In embodiments according to the first aspect or the second aspect, the anode assembly further includes a removable internal anode housing to which at least one of the sacrificial anodes is secured, wherein the anode housing also includes a plurality of slots, wherein the slots are configured to encourage fluid flow around the anode housing.
In embodiments according to the first aspect or the second aspect, the wellhead corrosion further comprises: an isolator assembly disposed to be positioned also above ground in the wellhead toolstring such that the isolator assembly isolates electrically an uphole portion of the wellhead toolstring from a downhole portion of the wellhead toolstring; wherein the isolator assembly is configured to isolate at least one wellhead tool in the wellhead toolstring electrically from the downhole portion of the wellhead toolstring when the at least one wellhead tool in the wellhead toolstring is positioned in the uphole portion of the wellhead toolstring between the anode assembly and the isolator assembly.
The foregoing has outlined rather broadly some of the features and technical advantages of the technology embodied in the disclosed corrosion resistant system designs, in order that the detailed description that follows may be better understood. Additional features and advantages of the disclosed technology may be described. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same inventive purposes of the disclosed technology, and that these equivalent constructions do not depart from the spirit and scope of the technology as described.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of embodiments described in detail below, and the advantages thereof, reference is now made to the following drawings, in which:
FIG. 1A illustrates, for orientation purposes, a conventional wellhead tool string 100 that might typically be deployed above ground during wireline operations with conventional union assembly 220 positioned near lubricators 25;
FIG. 1B illustrates, also for orientation purposes, a wellhead toolstring 110, similar to the lower portion of conventional tool string 100 of FIG. 1A, except with conventional union assembly 220 removed and replaced with corrosion resistant connection assemblies 300, anode assembly 400, upper anode assembly UA and isolator assembly 500;
FIGS. 2A and 2B illustrate, in section and elevation views, aspects of a conventional union assembly 220 enabling a connection (coupling) between lengths of conventional riser pipe 200 as might typically be deployed as shown in FIG. 1A;
FIG. 2C illustrates, in further section view, the conventional union assembly 220 also illustrated in FIGS. 2A and 2B;
FIGS. 3, 3A and 3B illustrate an embodiment of a corrosion resistant connection assembly 300 whose design improves on the conventional union assembly 220 illustrated on FIGS. 2A, 2B and 2C, in which FIG. 3 is an assembled perspective view, FIG. 3A is a section as shown on FIG. 3, and FIG. 3B is an exploded view;
FIGS. 4, 4A and 4B illustrate an embodiment of an anode assembly 400, in which FIG. 4 is an assembled perspective view, FIG. 4A is a section as shown on FIG. 4, and FIG. 4B is an exploded view;
FIGS. 5, 5A and 5B illustrate an embodiment of an isolator assembly 500, in which FIG. 5 is an assembled perspective view, FIG. 5A is a section as shown on FIG. 5, and FIG. 5B is an exploded view; and
FIG. 6 is a reference graphic showing various metals on a continuum of “most noble” to “least noble”.
DETAILED DESCRIPTION
Reference is now made to FIGS. 1A through 6 as listed above in describing embodiments of the disclosed corrosion resistant system in association with prior art embodiments on which the disclosed corrosion resistant system improves. FIGS. 1A and 1B are provided for orientation purposes. FIGS. 2A, 2B and 2C depict conventional union assembly 220 as an example of prior art connection designs on which the disclosed corrosion resistant system improves. FIGS. 3 through 5B depict embodiments of a new corrosion resistant system. FIG. 6 is a reference graphic showing various metals on a continuum of “most noble” to “least noble”, and therefore, by inference, also on a continuum of decreasing pitting resistance equivalent number (PREN) from left to right. FIGS. 1A through 6 should be viewed together. More particularly, FIGS. 1A and 2A through 2C should be viewed together when considering prior art designs, while FIGS. 1B and 3 through 6 should be viewed together when considering embodiments of the disclosed corrosion resistant system. Any part, item, or feature that is identified by part number on one of FIGS. 1A through 6 will have the same part number when illustrated on another of FIGS. 1A through 6. It will be understood that the embodiments as illustrated and described with respect to FIGS. 1A through 6 are exemplary, and the scope of this disclosure is not limited to such illustrated and described embodiments.
Subject matter on FIGS. 1A and 2A through 2C is described above in the Background section.
FIGS. 3, 3A and 3B illustrate an embodiment of a corrosion resistant connection assembly 300 whose design improves on the conventional union assembly 220 illustrated on FIGS. 2A, 2B and 2C. FIGS. 3, 3A and 3B should be viewed together and with further reference to FIG. 1B. FIG. 3 is an assembled perspective view of connection assembly 300. It will be understood on FIG. 3, with momentary reference to FIG. 1B, that deployments of connection assembly 300 may be configured to concatenate two riser pipes 200 together. Connection assembly 300 is disposed to concatenate a first riser pipe 200 to a second riser pipe 200, preferably above ground in wellhead toolstring 110. Riser pipes 200 each provide riser pipe threads 201 at each end. Advantageously, riser pipes 200 and riser pipe threads 201 may be consistent with FIG. 2A, for example, in which riser pipe threads 201 are male threads at each end to allow direct threading of multiple connections assemblies 300 onto multiple riser pipes 200 to form a string. The scope of this disclosure is not limited in this regard, however. Conventional adapters, stubs, unions and seals, for example, may be provided with connection assemblies 300 to enable threaded connection compatibility with riser pipes 200.
FIG. 3A is a section as shown on FIG. 3. Connection assembly 300 on FIG. 3A includes male union and female union 305, 310 each with corresponding internal female threads 304, 313 for enabling a threaded connection with male riser pipe threads 201 on riser pipes 200. Connection of male union 305 to female union 310 enables o-ring housing 325 to be interposed between first and second riser pipes 200 when connection assembly 300 concatenates first riser pipe 200 to a second riser pipe 200. Male union and female union 305, 310 each further advantageously provide corresponding male union and female union tightening recesses 308, 312 to receive operator tools to assist with conjoining male riser pipe threads 201 and male/female union internal female threads 304, 313. Threading of nut 320 over female union 310 enables connection of male union 305 to female union 310 with o-ring housing 325 interposed between male and female unions 305, 310. FIG. 3A shows that the assembly of connection assembly 300 involves initially placing nut 320 over first riser pipe 200 before male union 305 is threaded onto first riser pipe 200. FIG. 3A depicts annular rib 303 provided on the exterior of male union 305 to prevent nut 320 from sliding off male union 305 once nut 320, and male union 305 are assembled as shown. Then, as shown on FIG. 3A, nut 320 may be tightened over female union 310 by conjoining nut threads 321 and female union threads (for nut) 311. Nut 320 advantageously provides nut tightening recesses 322 to receive operator tools to assist with conjoining nut threads 321 and female union threads (for nut) 311.
FIG. 3A further shows o-ring housing 325 received into female union 310 within connection assembly 300. As such, with momentary reference to FIG. 1B, o-ring housing 325 is disposed to be interposed between first and second riser pipes 200 when the connection assembly 300 concatenates first riser pipe 200 to second riser pipe 300 via connection of first and second riser pipes 200 to male and female unions 305, 310. Male and female unions 305, 310 are dimensioned and positioned such that when nut 320 is fully threaded and tightened over female union 310, o-ring housing 325 presents o-rings 326 and o-ring backups 327 to seal first and second riser pipes 200 respectively against internal fluid leakage.
In some embodiments, such as those illustrated on FIG. 3A, connection assembly 300 may further provide first and second retaining rings 306, 307. Retaining rings 306, 307 are provided to retain components to facilitate threading and unthreading of connection assembly 300 together, especially at elevation. First retaining ring 306 retains nut 320 between first retaining ring 306 and annular rib 303. Second retaining ring 307 retains o-ring housing 325 within female union 310. To repeat from the Summary section above, once nut 320 and o-ring housing 325 are retained, rotation of second (lower) riser pipe 200 (with female union and o-ring housing installed) enables threaded engagement between female union threads 311 (for nut) and nut threads 321. Similarly, retention of the nut 320 by first retaining ring 306 and retention of o-ring housing 325 by second retaining ring 307 allows nut 320 and o-ring housing 325 to remain retained on the ends of first and second riser pipes 200 respectively once connection assembly 300 is disengaged by rotating second (lower) riser pipe in the opposite direction.
FIG. 3B is an exploded view of connection assembly 300, providing additional views of the subject matter illustrated on FIGS. 3 and 3A as described immediately above. In addition to showing features also illustrated on FIGS. 3 and 3A, FIG. 3B shows first retaining ring recess 309 on male union 305 for receiving first retaining ring 306. FIG. 3B further shows second retaining ring recess 314 on female union 310 for receiving second retaining ring 307. FIG. 3B further shows o-ring recesses 328 on o-ring housing 325 for receiving o-rings 326 and o-ring backups 327.
It will therefore be appreciated from FIGS. 3 through 3B that connection assembly 300 addresses the prior art corrosion issues identified in the Background section above, and described with reference to prior art union assembly 220 on FIGS. 2A, 2B and 2C. Embodiments of connection assembly 300 provide male union 305, o-ring housing 325 and female union 310 in the internal fluid flow path, and in some embodiments all of these components are made from the same unitary material. In disclosed embodiments herein, male union 305, o-ring housing 325 and female union 310 may all be made from 28 Chrome, the same material commonly selected for riser pipes 200 in oilfield deployments such as fracking. As described above in the Summary section, 28 Chrome provides superior resistance to pitting corrosion and crevice corrosion than, say, L80 or P110, as used in conventional union assemblies. Further, uniformity of a material such as 28 Chrome throughout the internal flow path avoids a potential for galvanic corrosion within connection assembly 300.
Further, as also shown on FIGS. 3A and 3B, embodiments of connection assembly 300 provide o-ring housing 325 interposed between male and female unions 305, 310. O-ring housing 325 is advantageously sized, dimensioned and located so that o-rings 326 are positioned to seal riser pipes 200 when riser pipes 200 are abutted in a fully-assembled connection assembly 300. By contrast, with momentary reference to FIG. 2A, prior art union assembly 220 (without an o-ring housing) requires the shoulder end of one riser pipe 200 to abut male union 228 and the shoulder end of the other riser pipe 200 to abut female union 226 once union assembly 220 is fully assembled. As described above in the Background section, these riser pipe shoulder abutments in prior art union assembly 200 are potential hot spots for galvanic corrosion. Provision of a suitably located o-ring housing 325 in connection assembly 300 obviates the shoulder abutments seen in a conventional union assembly. Corresponding potential galvanic corrosion hot spots are also avoided.
FIGS. 3A and 3B also depict o-ring backups 327 to support o-rings 326. As is known conventionally, o-ring backups 327 are restraints provided to limit o-rings 326 from deformation under pressure where such deformation might compromise the seal provided by o-rings 326. Embodiments of connection assembly 300 described herein provide conventional elastomer o-rings. Examples of suitable elastomer o-ring styles include K127 and S131, although the scope of this disclosure is not limited in this regard. Alternatively, in some embodiments, o-rings may be made from a polyurethane material such as, for example, HPU 95A.
Nut 320 on connection assembly 300 may continue to be made from L80 or P110 (for example) as is conventional. FIG. 3A shows that nut 320 is not in the internal flow path of connection assembly 300 and so is not susceptible to the various forms of corrosion discussed in the Background section above.
The scope of this disclosure is further not limited to the materials suggested or described herein for riser pipes 200, male union 305, female union 310, nut 320 and/or o-ring housing 325. Factors such as cost and availability of materials inevitably influence choice of materials. Alternative embodiments of connection assembly 300 described herein may provide different materials while still achieving some or all of the technical advantages set forth in the Summary section above. For example, alternative embodiments of connection assembly 300 may provide components made from Inconel 718 instead of 28 Chrome. Inconel 718 is a high-strength, corrosion resistant nickel-chromium alloy suitable for machined components. Inconel 718 and 28 Chrome have comparable corrosion resistances, suggesting comparable resistance to pitting corrosion and crevice corrosion. Inconel 718 and 28 Chrome are nonetheless different metals. Care may be needed in use of Inconel 718 with other 28 Chrome components, or with 28 Chrome riser pipes, in order to minimize the potential for galvanic corrosion.
As noted above, first and second riser pipes 200 on FIG. 2A, for example, each provide male riser pipe threads 201. Connection assembly 300 on FIGS. 3 through 3B includes male union and female union 305, 310 each with corresponding internal female threads 304, 313 for enabling a threaded connection with male riser pipe threads 201 on riser pipes 200. Non-limiting examples of such a threaded connection between riser pipes 200 and male or female union 305, 310 include an ACME thread interface such as a 6.063-6 stub ACME interface. The scope of this disclosure is not limited, however, to any particular thread interface between riser pipes 200 and male or female union 305, 310. Further, as also noted above, conventional adapters, stubs, unions and seals, for example, may be provided with connection assemblies 300 to enable threaded connection compatibility with riser pipes 200.
FIGS. 4, 4A and 4B illustrate an embodiment of an anode assembly 400, in which FIG. 4 is an assembled perspective view, FIG. 4A is a section as shown on FIG. 4, and FIG. 4B is an exploded view. FIGS. 4, 4A and 4B should be viewed together. FIG. 4 shows assembled anode assembly 400 comprises anode cover 401 secured to adapter flange 430 by conventional anode assembly fasteners 441. FIG. 4 also shows anode cover threads 402 for attaching (directly or ultimately) to riser pipe 200 or other tools as shown on FIG. 1B. Riser pipes 200 may provide riser pipe threads to allow direct threading onto anode cover threads 402. Alternatively, conventional adapters, stubs, unions and seals, for example, may be provided with anode assembly 400 to enable threaded connection compatibility with riser pipes 200.
FIG. 4A depicts anode housing 410 disposed within anode assembly 400. Anode housing 410 provides anode housing threads 413 configured to mate with adapter flange anode housing threads 431 to secure anode housing 410 to adapter flange 430. In illustrated embodiments, anode housing 410 provides anode housing tightening lugs 415 and adapter flange 430 provides tightening recesses 433 to receive hand tools, for example, to assist with such securement.
Anode housing 410 on FIG. 4A further provides bars 412 and sacrificial anodes 411 to enable galvanic protection (or “cathodic” protection) and associated corrosion resistance. In some embodiments, bars 412 are steel and anodes 411 are a zinc-aluminum alloy. Bars 412 are affixed rigidly through and/or to anodes 411. In such embodiments, bars 412 may be conventionally attached to anodes 411 such as via welding. Anode assembly 400 thus includes at least one sacrificial anode 411 acting as a corrosion inhibitor for at least one wellhead tool in wellhead toolstring 110 on FIG. 1B when anode assembly 400 is also positioned above ground in wellhead toolstring 110. Anode assembly 400 on FIG. 4A is further engineered in some embodiments to promote fluid flow and circulation in order to enhance the galvanic protection (or “cathodic” protection) provided by anodes 411. Slots 414 in anode housing 410 allow fluid to circulate through anode housing 410 and around anodes 411. Anode housing 410 is preferably removable. In this way, anode assembly 400 includes a removable anode housing 410 to which at least one of the sacrificial anodes 411 is secured. Anode housing 410 also includes a plurality of slots 414 configured to encourage fluid flow around anode housing 410. Wave spring 421 applies spring bias between adapter flange 430 and anode housing 410 to promote electrical contact between anode housing threads 413 and adapter flange anode housing threads 431.
FIG. 4A further depicts adapter flange o-ring 422 and adapter flange o-ring backup 423 deployed in adapter flange o-ring annular recess 424 on adapter flange 430. O-ring 422 and o-ring backup 423 provide a conventional fluid seal between adapter flange 430 and anode cover 401 when anode assembly 400 is assembled. Illustrated embodiments according to FIG. 4A also provide adapter flange chamfer 425 on adapter flange 430. Chamfer 425 assists with draining fluid out of anode assembly 400 during disassembly. Ideally fluid will drain out of anode assembly 400 through the interior of anode housing 410. Some of slots 414 on anode housing 410 may be positioned such that, during disassembly of anode assembly 400, fluid outside anode housing 410 may drain down chamfer 425 and back into the interior of anode housing 410 through such positioned slots 414. FIG. 4A illustrates such a drainage configuration.
FIG. 4A further depicts adapter flange internal riser threads 432. With momentary reference to FIG. 1B, adapter flange internal riser threads 432 are for threaded attachment of anode assembly 400 to riser pipe 200 or another wellhead tool in wellhead toolstring 110. Such threaded attachment may be via direct threading, or alternatively with conventional adapters, stubs, unions and seals, for example, interposed to enable threaded connection compatibility.
FIG. 4B is an exploded view of anode assembly 400. FIG. 4B further illustrates the subject matter of FIGS. 4 and 4A as described in the immediately preceding paragraphs.
As noted above, anodes 411 are made of a zinc-aluminum alloy in some embodiments. The scope of this disclosure is not limited in this regard, however. Anodes 411 may be made of other materials and alloys known to be less noble, and thereby more sacrificially effective in galvanic protection systems.
As noted above, FIG. 6 is a reference graphic showing various metals on a continuum of “most noble” to “least noble”. The source of FIG. 6 is a reference discussion of “Galvanic of North America found at Corrosion” by the Specialty Steel Industry https://www.ssina.com/education/corrosion/galvanic-corrosion/. FIG. 6 shows zinc, aluminum and related alloys on the right side of the continuum towards least noble and most anodic metals.
In contrast, as also described earlier, components such as riser pipes 200 and o-ring housing 325 with internal surfaces contacting corrosive fluid are preferably made from 28 Chrome, Inconel 718, L80 or P110, for example. These alloys are all found on the left side of FIG. 6 among the stainless steels and nickel-chromium alloys. The left side of FIG. 6 shows the most noble and least anodic metals. Galvanic corrosion in wellhead toolstring 110 will therefore prefer anodes 411 to components such as riser pipes 200 or o-ring housing 325, or indeed other wellhead tool components with internal surfaces presenting a more noble metal.
Further, in the event there is any residual galvanic corrosion not directed to anodes 411, embodiments of the disclosed corrosion resistant system look to pitting resistance equivalent number (or PREN) to protect smaller and potentially more valuable components such as o-ring housing 325 from galvanic corrosion over larger components such as riser pipes 200. The objective is to direct any residual galvanic corrosion to the larger components with larger corrosive fluid contact areas, in order to slow down the overall corrosion rate towards a component failure.
A metal's PREN is generally understood to correlate to how “noble” the metal is. The higher a metal's PREN, the more noble and cathodic its position will be on the continuum shown on FIG. 6. For reference, 28 Chrome (discussed earlier) typically has a PREN of about 39. Materials such as Inconel 718, L80 and P110 each have a slightly lower PREN, but still considerably higher than, for example, more anodic and less noble metals such as zinc and aluminum and their alloys. It will therefore be understood that to protect smaller and potentially more valuable components such as o-ring housing 325 from galvanic corrosion over larger components such as riser pipes 200, the PREN of o-ring housing 325 (designated as PRENH) should be no more than slightly lower than, and preferably greater than, the PRENs of both riser pipes 200 connected to o-ring housing 325 (such riser pipe PRENs designated as PREN1 and PREN2 respectively). Expressed arithmetically, preferably:
- PRENH-PREN1 is in a range between about −5 and +∞; and
- PRENH-PREN2 is in a range between about −5 and +∞.
In this way, riser pipes 200 that are engineered to have PRENs that are generally lower than PRENH will draw galvanic corrosion away from o-ring housing 325.
In many embodiments, the PRENs of riser pipes 200 will be substantially (or nominally) the same, in which cases the PREN designations of PREN1 and PREN2 will either be the same, or substantially or nominally the same. The scope of this disclosure is not limited in this regard, however. It should be further noted that the scope of this disclosure also includes embodiments where PRENH is slightly lower than PREN1 or PREN2 (specifically, where PREN1 or PREN2 subtracted from PRENH may decrease to about −5). This aspect accommodates that in many embodiments, PRENH will be substantially (or nominally) the same as PREN1 and PREN2 because riser pipes 200 and o-ring housing 325 are each formed from the same unitary material. However, different manufacturers offer the same material or comparable materials having slightly different compositions and properties and so the PRENs may not be exactly the same. Further, although PREN is a reliable parameter, its calculation is not a precise science from material to material. Thus, the scope of this disclosure contemplates that PREN1 or PREN2 subtracted from PRENH may decrease to about −5 in order to accommodate small PREN variations subsisting in the selection of a particular manufacturer or material.
Further, components in the corrosive fluid flow path (such as o-ring housing 325 and riser pipes 200) will be formed from a unitary material in many embodiments. However, the scope of this disclosure is not limited to unitary material construction and may extend to embodiments with coatings or inserts, for example, on internal surfaces of components in the corrosive fluid flow path. In such embodiments, a first riser pipe 200 has a first riser internal surface, the o-ring housing 325 has a housing internal surface and a second riser pipe 200 has a second internal surface. The first riser internal surface, the housing internal surface and the second riser internal surface are contiguous when connection assembly 300 concatenates the first riser pipe 200 to the second riser pipe 200. The first riser internal surface presents a metal designated as PREN1, the second riser internal surface presents a metal designated as PREN2, and the housing internal surface presents a metal designated as PRENH. In some embodiments, any of the first riser internal surface, the housing internal surface and/or the second riser internal surface may present a metal selected from 28 Chrome, Inconel 718, L80 or P110.
Referring now again to FIG. 1B, upper anode assembly UA is similar in design to embodiments of anode assembly 400 described herein and illustrated with reference to FIGS. 4, 4A and 4B. Some embodiments of upper anode assembly UA are smaller than corresponding embodiments of anode assembly 400, and may deploy annular “bracelet”-shaped anodes inside rather than the longitudinally-oriented straight anodes 411 deployed in anode assembly 400. In some embodiments of wellhead toolstring 110 on FIG. 1B, anode assembly 400 is a first anode assembly, and upper anode assembly UA is a second anode assembly. The second anode assembly disposed to be positioned also above ground in wellhead toolstring 110 such that at least one wellhead tool in wellhead toolstring 110 is interposed between the first anode assembly and the second anode assembly.
FIGS. 5, 5A and 5B illustrate an embodiment of an isolator assembly 500. As noted above in the Summary section, isolator assembly 500 may be provided in some embodiments in order to focus galvanic protection in wellhead toolstring 110. Isolator assembly 500 is advantageously deployed to provide an electrical barrier to any potential galvanic protection that anode assembly 400 might otherwise seek to provide further downhole into the drill string. FIG. 5 is an assembled perspective view of isolator assembly 500. FIG. 5A is a section as shown on FIG. 5, and FIG. 5B is an exploded view. FIGS. 5, 5A and 5B should be viewed together. FIG. 5 shows assembled isolator assembly 500 comprises isolator flange 510 secured to isolator adapter 530 by conventional isolator assembly fasteners 501.
FIG. 5A depicts isolator flange threads 511 on isolator flange 510 for attaching (directly or ultimately) to riser pipe 200 or other tools as shown on FIG. 1B. Riser pipes 200 or other tools may provide threads to allow direct threading onto isolator flange threads 511. Alternatively, conventional adapters, stubs, unions and seals, for example, may be provided with isolator assembly 500 to enable threaded connection compatibility with riser pipes 200 or other tools. In some illustrated embodiments, isolator flange tightening recesses 512 may be provided in isolator flange 510 for receiving hand tools, for example, to assist with threaded securement.
FIGS. 5 and 5A show force distribution plate 502 and first isolation gasket 503A interposed between isolator assembly fasteners 501 and isolator flange 510. FIGS. 5A and 5B show that first isolation gasket 503A is advantageously received in first isolation gasket receptacle 505 in isolator flange 510. Force distribution plate 502 is made from metal and distributes point loads exerted by tightened isolator assembly fasteners 501 around first isolation gasket 503A. First isolation gasket 503A provides electrical isolation of isolator assembly fasteners 501 from isolator flange 510. In some embodiments, first isolation gasket 503A is made from a hard, non-conductive material such as Garolite. Garolite is known as a fiberglass-epoxy laminate composite material with a high compression modulus. Garolite's high compression modulus allows isolation fasteners 501 to be secured tightly with confidence they will not loosen responsive to possible strain creep in the isolation gasket material.
FIGS. 5A and 5B further show isolation sleeves 504 received into isolator flange holes 513 in isolator flange 510. Isolation sleeves 504 provide further electrical isolation of isolator assembly fasteners 501 from isolator flange 510. In some embodiments, isolation sleeves 504 may be made from a non-conductive polymer such as polyethylene. In some embodiments, isolation sleeves 504 may be pre-fabricated cylinders received into isolator flange holes 513. In other embodiments, solid pieces of isolator sleeve material may be cast into isolator flange holes 513 and then drilled out to suit.
FIGS. 5A and 5B further illustrate that isolator flange 510 and isolator adapter 530 are separated by second isolation gasket 503B and isolation seal 524. Isolation seal 524 is received into isolation seal receptacle 525 in isolator flange 510. Second isolation gasket 503B is received into second isolation gasket receptacle 533 in isolator adapter 530. Second isolation gasket 503B and isolation seal 524 combine to provide further electrical isolation of isolator adapter 530 from isolator flange 510. In some embodiments, second isolation gasket 503B is similar to first isolation gasket 503A as described above and made from a hard, non-conductive material such as Garolite. In some embodiments, isolation seal 524 is made from a non-conductive, resilient polymer such as Teflon (or alternatively polyethylene).
FIG. 5A further depicts o-rings 521 providing addition sealing either side of isolation seal 524. O-rings 521 and o-ring backups 522 are received in o-ring annular recesses 523 (one recess 523 provided on each of isolator flange 510 and isolator adapter 530). O-ring annular recesses 523 are beveled in some embodiments in order to promote o-ring retention and effective sealing.
FIG. 5A further illustrates isolator adapter threads 531 on isolator adapter 530 for attaching (directly or ultimately) to riser pipe 200 or other tools as shown on FIG. 1B. Riser pipes 200 or other tools may provide threads to allow direct threading onto isolator adapter threads 531. Alternatively, conventional adapters, stubs, unions and seals, for example, may be provided with isolator assembly 500 to enable threaded connection compatibility with riser pipes 200 or other tools. In some illustrated embodiments, isolator adapter tightening recesses 532 may be provided in isolator adapter 530 for receiving hand tools, for example, to assist with threaded securement.
The scope of this disclosure in no way limits the described corrosion resistant system embodiments to specific sizes or models. Although disclosed with reference to an oilfield application in fracking service, currently envisaged embodiments make the disclosed technology available in various applications, and in various sizes and pressure ratings to suit the application. More specifically, currently envisaged embodiments of the described corrosion resistant system embodiments provide pressure ratings up to and including at least 15,000 psi MAWP. Currently envisaged sizes include internal diameters up to and including at least 8 inches internal diameter. It will nonetheless be understood that the foregoing sizes and performance metrics are exemplary only, and the scope of this disclosure is not limited in such regards.
Although corrosion resistant system embodiments have been described in this disclosure with reference to an exemplary application in hydraulic fracturing at a wellhead, alternative applications could include, for example, areas such as subsea connections, deep core drilling, offshore drilling, methane drilling, open hole applications, well pressure control, wireline operations, coil tubing operations, and mining operations. The scope of this disclosure is not limited to any particular application in which embodiments of the described corrosion resistant system may be deployed.
Although the material in this disclosure has been described in detail along with some of its technical advantages, it will be understood that various changes, substitutions and alterations may be made to the detailed embodiments without departing from the broader spirit and scope of such material as set forth in the following claims.
Patent Application
20250137358
