Toe flap valve for internal corrosion prevention in CCUS injection well tubing

Abstract

An apparatus for internal corrosion prevention is used for carbon capture utilization and storage injection well tubing. The apparatus may comprise a flap valve at a bottom end of the injection well tubing that operates by responding to elevated injection pressures and automatically closes upon injection cessation, effectively preventing a flow-back of formulation fluids into the injection well tubing.

Description

[0001] Patent CU-76259FG TOE FLAP VALVE FOR INTERNAL CORROSION PREVENTION IN CCUS INJECTION WELL TUBING CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to US non-provisional Patent Application No. 18 / 639,181, titled " TOE FLAP VALVE FOR INTERNAL CORROSION PREVENTION IN CCUS INJECTION WELL TUBING ", filed on Apr. 18, 2024, with the United States Patent Trademark Office, which is incorporated herein by reference in its entirety. Field of the Invention

[0002] The present invention relates to a valve for a downhole pipe in the oil and gas industry. More particularly, the present invention relates to a toe flap valve for internal corrosion prevention in carbon capture utilization storage (CCUS) injection well tubing. Background

[0003] Carbon Capture and Storage (CCS) technology has gained widespread acceptance and recognition as an effective tool in global carbon reduction initiatives. It stands as an essential technique to fulfill the goals outlined in the Paris Agreement. Nonetheless, the adoption of CCS has been hindered by its gradual implementation, largely attributed to its elevated expenses. Despite the presence of government incentives like the 45Q tax policy, the high costs persist. A notable contributor to these costs is the necessity of employing costly corrosion-resistant alloys for downhole tubing and tools. This requirement arises from the challenging downhole corrosion environment. For instance, the newly published AMPP Guide 21532-2023 recommends the use of the pricey 25Cr alloy. Consequently, any innovation capable of economizing material Patent CU-76259FG selection holds the potential to significantly enhance the global implementation of CCS technology.

[0004] In actuality, the injected CO2 stream does not exhibit corrosive properties, even in the presence of significant corrosive impurities. This is due to the fact that these gases do not cause metal corrosion in the absence of free water. Additionally, the CO2 stream undergoes thorough dehydration prior to transportation through carbon steel CO2 pipelines. In simpler terms, the challenge within the injection well stems not from the CO2 stream itself, but rather from the interaction between this stream and the water phase present within the reservoir.

[0005] Therefore, there is a need to have an apparatus for internal corrosion prevention in carbon capture utilization and storage injection well tubing.

[0006] These and other objectives and advantages of the present invention will become apparent from a reading of the attached specification. BRIEF SUMMARY OF THE INVENTION

[0008] Embodiments of the present invention include an apparatus for internal corrosion prevention in carbon capture utilization and storage injection well tubing. The apparatus comprises a flap valve at a bottom end of the injection well tubing that operates by responding to elevated injection pressures and automatically closes upon injection cessation, effectively preventing a flow-back of formulation fluids into the injection well tubing.

[0009] Optionally in any embodiment, the flap valve is rotatable between open and closed positions for controlling the flow in the injection well tubing. Patent CU-76259FG

[0010] Optionally in any embodiment, the flap valve comprises a flapper hinge about which the flap valve rotates.

[0011] Optionally in any embodiment, the flap valve comprises a valve seat to hold pressure exerted on an upstream flap valve face in the closed position.

[0012] Optionally in any embodiment, the flap valve comprises a hinge pin formed on said flap valve.

[0013] Optionally in any embodiment, the flap valve comprises a torsion spring means being loaded in torsion as the flap valve rotates from the closed to the open position to exert a restoring force for rotating the valve flapper to the closed position.

[0014] Optionally in any embodiment, the torsion spring means has one end connects and biases on an outer surface of the flap valve, while the other end connects and biases on the outer surface of the injection well tubing.

[0015] Optionally in any embodiment, the torsion spring means has both ends that connect and bias on the outer surface of the injection well tubing.

[0016] In another embodiment, a valve may be used in controlling flow in an injection well tubing. The injection well tubing may have a first end and a second end in a downhole injection well tubing. The valve may comprise a flap valve having a torsion spring means with one end connects and biases on an outer surface of the flap valve, while the other end connects and biases on the outer surface of the injection well tubing, wherein the flap valve comprises a valve seat to hold pressure exerted on an outer surface of the flap valve in the closed position, wherein area that the valve seat covers is substantially the same as the area of the inner diameter of injection well tubing. Patent CU-76259FG

[0017] Optionally in any embodiment, the flap valve is rotatable to open and close the bore of the injection well tubing at the second end of the injection well tubing while the first end of the injection well is located at the surface of land.

[0018] Optionally in any embodiment, the flap valve comprises a flapper hinge about which the flap valve rotates.

[0019] Optionally in any embodiment, the flap valve comprises a valve seat to hold pressure exerted on an outer surface of the flap valve in the closed position.

[0020] Optionally in any embodiment, the flapper hinge comprises a hinge pin formed on said flap valve.

[0021] Optionally in any embodiment, the torsion spring means is secured to the hinge pin.

[0022] Optionally in any embodiment, the torsion spring means is loaded in torsion as the flap valve rotates from the closed to the open position to exert a restoring force for rotating the valve flapper to the closed position.

[0023] Optionally in any embodiment, the spring means comprises a coil spring, rotation of said flap valve about an axis of rotation to open said flapper loading said springs in torsion.

[0024] In further embodiment, a flap valve for internal corrosion prevention in CCUS injection well tubing, comprises a flap that moves into contact with the tubing to create a tight seal when the injection pressure is above a certain threshold; and a spring means comprising a coil spring, rotation of said flap valve about an axis of rotation to open said flap loading said spring means in torsion, a valve flapper rotatable between open and closed positions for controlling the flow in the fluid transmission conduit, wherein Patent CU-76259FG the flap valve's operation neither constrains the injection flow rate nor induces the Joule- Thomson effect.

[0025] Optionally in any embodiment, the torsion spring means comprises a coil springs, rotation of said valve flapper about said axis of rotation to open said flap loading said springs in torsion.

[0026] Optionally in any embodiment, the torsion spring means has one end connects and biases on an outer surface of the flap valve, while the other end connects and biases on the outer surface of the injection well tubing.

[0027] Optionally in any embodiment, the torsion spring means has both ends connects and biases on the outer surface of the injection well tubing. BRIEF DESCRIPTION OF DRAWINGS

[0028] FIG. 1 is a perspective view of a flap valve according to one exemplary embodiment.

[0029] FIG.2 is a perspective view of a flap valve according to another exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0030] Before the description of the embodiment, terminology, methodology, systems, and materials are described; it is to be understood that this disclosure is not limited to the particular terminologies, methodologies, systems, and materials described, as these may vary. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions of embodiments only, and is not Patent CU-76259FG intended to limit the scope of embodiments. For example, as used herein, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. In addition, the word “comprising” as used herein is intended to mean “including but not limited to.” Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.

[0031] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as size, weight, reaction conditions and so forth used in the specification and claims are to the understood as being modified in all instances by the term “about”.

[0032] Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0033] As used herein, the term “about” means plus or minus 10% of the numerical value of the number with which it is being used. Therefore, about 50% means in the range of 45%-55%.

[0034] The presented innovations introduces a distinctive design for the toe flap valve, effectively addressing the flow-back fluid challenge. Referring to FIG.1, a flap valve assemblage embodying this invention is shown in assembled relationship within an injection well tubing 140. Patent CU-76259FG

[0035] This design unequivocally eradicates the root cause of any corrosion concerns. Additionally, it is noteworthy that the flap valve configuration at the well's bottom does not induce any alterations in CO2 pressure—meaning, there is no Joule-Thomson effect. Consequently, this design also obviates the risk of low-temperature cracking.

[0036] During the injection phase at the wellbore’s bottom, formation water becomes saturated with CO₂. The injection of dry supercritical CO₂ is seen as a step with reduced corrosion risk, as the expulsion of water occurs during this process. However, when the well experiences a shut-in, whether it is brief or extended, the wellhead temperature drops due to supercritical CO₂ vaporization. This results in a coexistence of the two phases at the wellhead, causing the precipitation of free water from its initial supercritical state. This occurrence, attributed to the lower solubility of water in CO₂ gas compared to supercritical CO₂, gives rise to corrosion challenges at the well's upper section. In the case of extended shut-ins, there is no doubt that direct contact with flow- back fluid exacerbates the corrosion issues at the bottom. Different from traditional oil and gas production wells, in the CCS or CCUS injection wells, shut-in is frequently mainly due to intermittent operation process

[0028] Beyond the requirement for materials to withstand these harsh corrosion- inducing conditions, they must also possess sufficient toughness to withstand low temperatures resulting from the Joule-Thomson effect. An extreme hypothetical involves an uncontrolled and unexpected well depressurization down to atmospheric pressure, leading to a CO₂ temperature drop to -78.5°C. In such a scenario, modeling indicates metallic temperatures would closely approach the CO₂ triple point (-56.6°C). This severe cold would necessitate the selection of specialized and more expensive corrosion- Patent CU-76259FG resistant alloys (CRA) capable of enduring such low temperatures. From this detailed process, it becomes evident that all corrosion issues stem from the formulation fluids' flow-back after the well's shut-in. The presence of these formulation fluids in the flow- back significantly contributes to the corrosion problems. The core corrosion challenges would cease to exist if measures were taken to prevent the flow-back of these formulation fluids into the tubing.

[0029] As shown in FIG. 1, an apparatus 100 for internal corrosion prevention in carbon capture utilization and storage injection well tubing 140 may comprise a flap valve 120 at a bottom end 146 of the injection well tubing 140 that operates by responding to elevated injection pressures and automatically closes upon injection cessation, effectively preventing a flow-back of formulation fluids into the injection well tubing 140.

[0030] In one embodiment, the flap valve 120 may contact with the tubing to create a tight seal when the injection pressure is below a certain threshold, such as atmospheric pressure, for example.

[0031] In one embodiment, the flap valve 120 may be rotatable between open and closed position for controlling the flow in the injection well tubing. The flap valve 120 may further comprise a flapper hinge 130 about which the flap valve 120 rotates.

[0032] In one embodiment, the flap valve 120 may further comprise a valve seat 150 to hold pressure exerted on an outer surface 160 in the closed position. The valve seat 150 defines at its bottom end an annular, cylindrically shaped sealing surface. The area that the valve seat 150 covers is substantially the same as the area of the inner diameter injection well tubing. The circumference of the valve seat 150 may be Patent CU-76259FG substantially same as that of the inside injection well tubing. An elastomeric seal may be inserted in such surface.

[0033] In one embodiment, the flapper hinge 130 may comprise a hinge pin 170 formed on said flap valve 120. In one embodiment, the flap valve 120 may further comprise a torsion spring means 180 being loaded in torsion as the flap valve 120 rotates from the closed to the open position to exert a restoring force for rotating the valve flapper 120 to the closed position.

[0034] When the flap valve 120 is pivoted about hinge pin 170 to its substantially vertical, open position as shown in FIG.1, it provides unrestricted fluid passage through such bore. The flap valve 120 may be shifted from its horizontal closed position to its substantially vertical open position by the downward movement of fluid, such as liquid carbon dioxide.

[0035] It will be apparent to those skilled in the art that the torsion spring means 180 is in torsion relative to the flap valve 120 so that the pivotal movement of the flap valve 120 from its horizontal closed position to its vertical open position shown in FIG.1 is opposed by a spring bias produced by the torsionally winding of the torsion spring means 180. Thus, the flap valve 120 is normally biased to its closed position and may return to such position whenever there is a shut-in either a short term shut-in or long term shut-in.

[0036] The flap valve 120 may have a ridge 190 on a central outer surface 160 of the flap valve 120 to make it much more sturdy and withhold the pressure builds up during the shut-in. Patent CU-76259FG

[0037] In one embodiment, the torsion spring means 180 has one end 182 that connects and biases on the outer surface 160 of the flap valve 120, while the other end 184 connects and biases on the outer surface of the injection well tubing 140.

[0038] In another embodiment, as shown in FIG.2, the torsion spring means may be a double torsion spring, which has springs 210 and 220 with both ends 212, 222 respectively connecting and biasing on the outer surface of the injection well tubing 140. The torsion spring means 210 and 220 have another merged end 226 connecting and biasing on the outer surface of the flap valve 120.

[0039] Still in FIG.2, the flap valve 120 has a curved configuration as compared to substantially flat configuration at the bottom of flap valve 120 shown in FIG.1. It will be understood that by those skilled in the art that both a curved flow tube and a curved flapper are not essentially related to the position of the spring utilized herein. The spring can be employed with a more conventional injection well tubing and flapper valve configuration. Furthermore, the curved flap valve configuration, and annular torsion spring, can be employed with an injection well tubing having a flat end and still achieve a significant increase in flow area.

[0040] Throughout the injection process, the valve operates by responding to elevated injection pressures. Positioned at the tubing's bottom end, the valve's operation neither constrains the injection flow rate nor induces the Joule-Thomson effect. Upon injection cessation, this flap valve automatically closes, effectively preventing the flow- back of formulation fluids. This action decisively eliminates all the factors contributing to corrosion issues. Functioning as a check valve, this flap valve can be designed and manufactured to achieve gas-tight sealing. Patent CU-76259FG

[0041] While this valve, along with the outer diameter of the tubing beneath the packer, remains exposed to downhole fluids, they are crafted from corrosion-resistant alloys (CRA) like 25Cr or Super 13Cr. On the other hand, the tubing section above the packer can be constructed from cost-effective low-alloy steel, such as L80. As a result, significant cost savings can be realized.

[0042] The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated structures, construction and method can be made without departing from the true spirit of the invention.

Claims

Patent CU-76259FG CLAIMS We claim:

1. An apparatus for internal corrosion prevention in carbon capture utilization and storage injection well tubing, comprising: a flap valve at a bottom end of the injection well tubing that operates by responding to elevated injection pressures and automatically closes upon injection cessation, effectively preventing a flow-back of formulation fluids into the injection well tubing.

2. The apparatus of claim 1, wherein the flap valve is rotatable between open and closed positions for controlling the flow in the injection well tubing.

3. The apparatus of claim 1 or 2, further comprising a flapper hinge about which the flap valve rotates.

4. The apparatus of any one of claims 1-3 further comprising a valve seat to hold pressure exerted on an outer surface of the flap valve in the closed position.

5. The apparatus of any one of claims 1-4, wherein said flapper hinge comprises a hinge pin formed on said flap valve.

6. The apparatus of any one of claims 1-5, further comprising a torsion spring means being loaded in torsion as the flap valve rotates from the closed to the open position to exert a restoring force for rotating the valve flapper to the closed position.Patent CU-76259FG 7. The apparatus of any one of claims 1-6, wherein the torsion spring means has one end connects and biases on the outer surface of the flap valve, while the other end connects and biases on the outer surface of the injection well tubing.

8. The apparatus of any one of claims 1-7, wherein the torsion spring means has both ends connects and biases on the outer surface of the injection well tubing.

9. A valve for use in controlling flow in an injection well tubing having a first end and a second end in a downhole injection well tubing, comprising: a flap valve having a torsion spring means with one end connects and biases on an outer surface of the flap valve, while the other end connects and biases on the outer surface of the injection well tubing, wherein the flap valve comprises a valve seat to hold pressure exerted on an outer surface of the flap valve in the closed position, wherein area that the valve seat covers is substantially the same as the area of the inner diameter of injection well tubing.

10. The valve of claim 9, wherein the flap valve is rotatable to open and close the bore of the injection well tubing at the second end of the injection well tubing while the first end of the injection well is located at the surface of land.

11. The valve of any one of claims 9-10, further comprising a flapper hinge about which the flap valve rotates.Patent CU-76259FG 12. The valve of any one of claims 9-11 further wherein the flap valve is configured to move into contact with the injection well tubing to create a tight seal when the injection pressure is below a certain threshold.

13. The valve of any one of claims 9-12, wherein said flapper hinge comprises a hinge pin formed on said flap valve.

14. The valve of any one of claims 9-13, wherein the torsion spring means is secured to the hinge pin.

15. The valve of any one of claims 9-14, wherein the torsion spring means is loaded in torsion as the flap valve rotates from the closed to the open position to exert a restoring force for rotating the valve flapper to the closed position.

16. The valve of any one of claims 9-15, wherein said spring means comprises a coil spring, rotation of said flap valve about an axis of rotation to open said flap valve loading said springs in torsion.

17. A flap valve for internal corrosion prevention in CCUS injection well tubing, contacting with the tubing to create a tight seal when the injection pressure is below a certain threshold, comprising: a torsion spring means comprising a coil spring, rotation of said flap valve about an axis of rotation to open said flap loading said spring means in torsion, a valve flapper rotatable between open and closed positions for controlling the flow in the fluidPatent CU-76259FG transmission conduit, wherein the flap valve's operation neither constrains the injection flow rate nor induces the Joule-Thomson effect.

18. The valve of claim 17, wherein said torsion spring means comprises a coil springs, rotation of said valve flapper about said axis of rotation to open said flap loading said springs in torsion.

19. The valve of any one of claims 17-18, wherein the torsion spring means has one end that connects and biases on an outer surface of the flap valve, while the other end connects and biases on the outer surface of the injection well tubing.

20. The valve of any one of claims 17-19, wherein the torsion spring means has both ends connects and biases on the outer surface of the injection well tubing.

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