System for measuring corrosion and scaling on injector well bottoms

Abstract

The invention relates to a flow-blocking valve that is used in selective strings of injector wells (blind valve) and which, while maintaining the dimensions and external design of a conventional valve, is able to accommodate internally, in a protected and separate manner, a coupon that is disposed in the upper part and which will be exposed only to the injected water, and another coupon that is disposed in the lower part and which will be exposed to the return fluids of the deposit. The device allows the phenomena of corrosion and / or scaling to be assessed directly in relation to the well bottom conditions to which the valves controlling the injected flow in each area are subjected.

Description

[0001] CORROSION AND SCALE MEASURING SYSTEM AT THE BOTTOM OF INJECTION WELLS

[0002] GENERAL DESCRIPTION OF THE INVENTION

[0003] In oil fields where water injection is used as a secondary recovery method to maintain and increase hydrocarbon recovery, it is common for produced water to be the injection fluid, ensuring a closed process, avoiding discharge into water sources and thus contributing to environmental protection. Fluids produced from the reservoir have physicochemical characteristics that, when in contact with surface and subsurface equipment, promote the development of corrosion and scaling, among others, depending on the metallurgy of the steels with which said equipment is constructed.

[0004] For this reason, this invention was developed to deliver coupons that can quantify these fluid-steel interactions to the bottom of the well and securely install them within the mandrel pockets in the injection string of each well. This seeks to mitigate the risks associated with coupon failure and collect data directly at the source where the phenomena being evaluated occur.

[0005] The ability to directly quantify corrosion and scaling downhole gives the production and injection engineering team the ability to map these variables throughout the field, across different sectors, depths, injection characteristics, and over time. With quality information, it will be possible to appropriately manage these phenomena, whether through chemical treatment, new materials, and / or coatings that will allow for greater control over the integrity of surface facilities and downhole completions in the future.

[0006] The internal design of this tool is conceived to allow the entry of injection or return fluids, protect the coupons, and ensure that they only make contact with said fluids. The materials used are stainless steel. The coupons are made of cast iron, carbon steel, or stainless steel. In addition, a design was developed that allows for easy handling, assembly, and disassembly, ultimately maximizing parts utilization. While the external configuration of this device is the standard used in selective water injection strings, it was taken to another level by developing a design that accommodates a greater number of upper and lower seals, positioned to ensure proper sealing, preventing fluid passage where required, thereby mitigating the risks associated with loosening and leaks in worn mandrels.The location and number of seals is adjustable, depending on the knowledge of the mandrel's condition. This allows for the placement of more or fewer upper seals, achieving greater or lesser anchoring and effective sealing against the mandrel pocket where it is installed.

[0007] The lower part of the tool is provided with a long tip that allows it to effectively ensure the opening of the check valves of the mandrels, allowing the return fluids to enter the invention tool and also being able to measure the effects of those fluids.

[0008] DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention relates to a blanking valve installed in the selective injection string of an injection well. It allows corrosion and scale to be measured at the bottom of injection wells. This system allows corrosion or scale coupons to be housed inside and protected, and then moved to the pockets of selective injection mandrels in water and / or improved water injection wells, and their seating is achieved with standard tools using cable units.

[0010] The general parts, from top to bottom of this blind valve, in the direction of flow, are: mechanical anchor assembly (1), injection sub (2), upper spacer (9), lower spacer (15), nose (18) and long tip (21). The internal parts, how they are connected to each other and how they work are described below.

[0011] The mechanical anchor assembly (1) is the standard for this type of valves and allows its installation and removal from the well, in its lower part it has a 25.4 mm box type thread, where the injection sub (2) is connected by a 25.4 mm pin type thread. The injection sub has strategically drilled 10.922 mm holes to allow the entry of the injection fluid directly to the upper filter (4) securely positioned inside the injection sub (2) supported by a safety ring (5) so that the injection fluid contacts the upper coupon (8). The injection sub (2) has a 28.575 mm pin lower thread to connect with the upper spacer (9).

[0012] The upper coupon holder (6) has an external geometry (6A) with a larger diameter at the top that allows it to be hung from the upper inner part of the injection sub (2), and also houses an internal cushioning seal (3). The upper coupon holder (6) guarantees the concentric location of the upper coupon (8) by means of two lower segments (6C) that have threaded holes (6B) through which two continuous thread studs (7) pass, securing the coupon to the two lower segments. This upper coupon consists of a sheet (8A) and two holes (8B and 8C) that allow it to be secured to the upper coupon holder (6), avoiding metal-to-metal contact.

[0013] The extension achieved with the design of the upper coupon holder (6) allows the upper coupon (8) to be housed in the upper internal part of the upper spacer (9) maintaining complete tightness and therefore the injection fluid will not be able to advance internally towards the lower part and in this way will not have contact with the other coupon and the return fluids.

[0014] The upper spacer (9), in its lower external part, has a diameter reduction where it houses 13 upper gasket seals (10) made of nitrile-kevlar for high pressure and temperature, which can be organized and adjusted in their spacing by means of the upper Teflon separator (11) or the larger upper Teflon separator (12). This customization of the seal spacing allows this tool to provide greater anchoring and a more effective seal against the mandrel pocket.

[0015] The upper spacer (9) connects with a 28.575 mm box upper thread to the lower part of the injection sub (2) and with a 25.4 mm pin external lower thread it connects to the lower spacer (15). The primary function of the lower spacer (15) is to accommodate the lower coupon holder (13) that holds the lower coupon (14) in such a way that it does not make contact with anything other than the return fluid.

[0016] The lower spacer (15) has a 0.375NC internal box concentric thread that allows the coupling of the lower coupon holder (13) by means of a 0.375NC pin thread (13A), remaining centered and supported. In turn, the lower coupon holder (13) holds the lower coupon (14) by means of a system similar to that of the upper coupon (8), that is, by means of two lower segments (13C) that have threaded holes (13B) through which two continuous thread studs (7) pass through, securing the coupon to the two lower segments. This lower coupon (14) consists of a sheet (14A) and two holes (14B and 14C) that allow it to be secured to the lower coupon holder (13), avoiding metal-to-metal contact.

[0017] The lower spacer (15), on its lower external part, has a diameter reduction to accommodate 10 unique lower packing seals (16) made of nitrile-kevlar, which can be organized and adjusted by means of a lower Teflon separator (17). This customization of the seal spacing allows this tool to provide greater anchoring and a more effective seal against the mandrel pocket.

[0018] The nose (18) has a 28.575 mm upper box thread, where the lower spacer (15) is connected. This nose has 10.922 mm holes in the lower part of it, which allow the entry of the return fluids from the well that will be in contact with the lower coupon (14) and thus achieve the evaluation of the corrosive or scaling phenomena caused by the interaction with these fluids.

[0019] The nose (18) has a design inside that allows it to house the lower filter (19), this filter has a circular shape and is housed in the lower inner part of the nose.

[0020] The nose tip (18) has a hole to allow the passage of a 3.175 mm bronze pin (20) which is a redundant safety control device for the long tip (21). This long tip (21) has a 0.375NC thread on the top, which allows it to be coupled to the nose (18). This long tip allows the opening of the check valves of the injection mandrels.

[0021] Once the downhole logging time is complete, the tool is brought to the surface to be disassembled and the coupons (upper and lower) recovered, following the relevant protocols to prevent contamination.

[0022] The external and internal configuration of this invention, constructed of stainless steel, is designed for linear assembly and has redundant external seals with a configuration that reduces the risks of loosening and leaks.

[0023] The application of this invention in fields with water injection or enhanced water injection will allow for a realistic mapping of the evolution of corrosion and scale problems, enabling more timely and accurate decisions to be made to optimize the injection process.

[0024] EXAMPLES

[0025] Downhole installation:

[0026] -Two injection wells were selected, located in sectors where corrosion had already been identified in the production wells.

[0027] -Two devices were installed using a cable unit, following a protocol previously defined in the field for lowering special tools into the well. This protocol basically recommends the tool's lowering and raising speeds and also recommends special care in handling these devices, which contain sensitive measurement systems.

[0028] -After 45 days the device was removed from each well, using a wire rope unit,

[0029] Results:

[0030] -The anchoring and watertightness tests, carried out in an above-ground workshop, were satisfactory.

[0031] -The installation and removal operations of the downhole device were carried out successfully and without incident.

[0032] -The coupons were found in place and without deformations.

[0033] -With the assistance of personnel specialized in handling these coupons, they were removed from the device and stored in their packaging.

[0034] -These were the results reported for each coupon, after applying the same procedure as those used on similar coupons installed on surface pipelines: TECHNOLOGY SECTOR

[0035] This device corresponds to the hydrocarbon extraction industry sector, specifically in fields undergoing enhanced recovery with water and / or polymer injection, using selective strings.

[0036] ANALYSIS OF THE STATE OF THE ART

[0037] Patent number US2022010654 AA, entitled "Downhole Scale and Corrosion Mitigation," relates to a system and method for injecting inhibitor fluids downhole and includes an injection tool. This injection tool consists of an elongated body with a storage space inside. It has a valve that can be closed to prevent the inhibitor fluid from escaping and open to provide a path for the inhibitor fluid to escape. A water sensor is in communication with said valve. In addition, it has a recharge line from an inhibitor fluid storage tank to the interior storage space. The injection tool is located on a support inside the well.

[0038] The basic difference with respect to the proposed system is that it is a system for injecting inhibitor fluid or chemical treatment downhole, designed to treat corrosion or scaling. The proposed system is designed to evaluate these corrosion and / or scaling phenomena downhole.

[0039] Patent number US2019086320 AA, entitled “DETERMINATION OF PIPE PROPERTIES IN A CORROSION INSPECTION” deals with systems and methods for detecting the characteristics of downhole pipes (e.g., casing and / or production tubing), such as their defects and estimating their thickness.The flaw detection method may comprise a tool consisting of at least a transmitter and a receiver; obtaining nominal parameters of the pipe; determining a defect profile for the pipes exposed in a wellbore; determining defect responses from the nominal parameters and the defect profile; calculating a gradient from the defect responses, the nominal responses, the nominal parameters, and the defect profile; taking downhole measurements for all pipes using the flaw detection tool; and calculating final solution parameters of the pipes using at least the downhole measurements, the nominal responses, the gradient, and the nominal parameters.

[0040] The basic difference with respect to the proposed system is that it is a system and methodology focused on downhole pipes to measure their nominal parameters and identify defects. The proposed system, on the other hand, is intended to evaluate corrosion and / or scaling phenomena that may occur downhole, specifically in the flow control valves of an injection well.

[0041] Patent number CN201016296, entitled “CALING AND CORROSION CONTROL APPARATUS FOR DOWNHOLE STRING IN WATER AND OIL WELLS,” relates to a model that provides a corrosion and scale detector for the downhole string. This detection device consists of an upper and a lower adapter that are installed together, then a spacer ring and a plug ring made of insulating material are placed on the lower adapter from bottom to top; and a sample ring is placed between each ring. The corrosion and scale detector for the downhole string can be placed on the production tubing and then taken out together with the downhole string to detect the corrosion and scale situation of the sample ring during well workover, in this way a scientific and effective detection of the corrosion and scale condition of the downhole string can be realized.This detector is especially beneficial for the downhole string of the water injection well.

[0042] The basic difference with respect to the proposed system is that it focuses on the production or injection tubing, installing rings that function as detection devices. The proposed system, on the other hand, uses coupons specifically installed inside flow control valves, which are then installed in the injection string of an injection well.

[0043] Patent number US2017226843 AA, entitled “DOWNHOLE CORROSION, EROSION, SCALE AND DEPOSIT MONITORING SYSTEM” is a tool for monitoring downhole conditions in a well, consisting of a first elongated segment with an axial protuberance having a reduced outside diameter. A second segment sized to mate with the first segment. A metal sample circumscribes the axial protuberance of the first segment such that an outside diameter surface of the metal sample defines an outside diameter of the tool. A connection assembly releasably secures the first body segment to the second body segment. This device is located inside the well, while the proposed system is specifically introduced into flow regulating valves that are in turn installed in the injection string of an injection well.

[0044] Patent number US2017191361 AA, titled “MULTI-PIPE CORROSION INSPECTION TOOL WITH HIGH-QUALITY VISUALIZATION” consists of a method for lowering a pipeline inspection tool with one or more sensors into the wellbore. An excitation signal is transmitted from the inspection tool and the response signals are measured with the sensors. The response signals are processed to obtain measurements. A map of the pipeline is then generated based on the measured responses, the map is divided into pipe ranges that extend along the pipe and each pipe range corresponds to a percentage of metal loss in the pipe. A photorealistic image is assigned to each pipe range based on the percentage of metal loss and then a two-dimensional (2D) or three-dimensional (3D) image is generated as a combination of each photorealistic image. The 2D or 3D image is then graphically displayed.This tool measures material loss from the pipe using sensors, while the proposed system measures corrosion also using a material loss method, directly on coupons installed inside flow control valves in the strings of an injection well.

[0045] In the review, there is no tool with these features and functionality for obtaining direct downhole information, specifically from water and / or polymer injection wells. What is available on the market for the industry are blind valves used to prevent the injection fluid from entering the reservoir in a controlled manner. This invention, in addition to serving as a blind valve, allows for obtaining the aforementioned data to evaluate downhole corrosion and / or scaling.

[0046] DESCRIPTION OF THE FIGURES

[0047] Figure 1. Parts of the corrosion and scale measuring system

[0048] Figure 2. Parts of the upper coupon holder and the lower coupon holder

[0049] Figure 3. Parts of the upper coupon and the lower coupon

Claims

CLAIMS 1. A system for measuring corrosion and scaling at the bottom of injection wells, characterized in that it comprises the following parts: • A mechanical anchor assembly (1), • An injection sub (2), • A top coupon holder (6) • An upper spacer (9), • A lower spacer (15), • A lower coupon holder (13) • A nose (18) and • A long tip (21).

2. The corrosion and scaling measurement system at the bottom of injection wells of claim 1, characterized in that the mechanical anchoring assembly (1) is standard for this type of valves and allows its installation and removal from the well, in its lower part it has a 25.4 mm box type thread, from where the injection sub (2) is connected by means of a 25.4 mm pin type thread.

3. The downhole corrosion and scale measurement system for injection wells of claim 1, characterized in that the injection sub has 10.922 mm holes drilled to allow the entry of the injection fluid directly to the upper filter (4) securely positioned within the injection sub (2) supported by a safety ring (5) such that the injection fluid contacts the upper coupon (8). Additionally, the injection sub (2) has a 28.575 mm lower pin thread to connect with the upper spacer (9).

4. The downhole corrosion and scaling measurement system for injection wells of claim 1, characterized in that the upper coupon holder (6) has an external geometry (6A) with a larger diameter at the top that allows it to be hung from the upper inner part of the injection sub (2), and also houses an internal damping seal (3). The upper coupon holder (6) guarantees the concentric location of the upper coupon (8) by means of two lower segments (6C) that have threaded holes (6B) through which two continuous thread studs (7) pass through, securing the coupon to the two lower segments. This upper coupon consists of a sheet (8A) and two holes (8B and 8C) which allow it to be secured to the upper coupon holder (6) avoiding metal-to-metal contact.

5. The corrosion and scaling measurement system at the bottom of injection wells of claim 1, characterized in that the upper coupon holder (6) allows the upper coupon (8) to be housed in the upper internal part of the upper spacer (9) to maintain tightness and therefore the injection fluid avoids advancing internally towards the lower part and in this way avoids contact with the other coupon and the return fluids.

6. The downhole corrosion and scaling measurement system for injection wells of claim 1, characterized in that the upper spacer (9), in its lower external part, has a diameter reduction where it houses 13 upper packing seals (10) made of nitrile-kevlar for high pressure and temperature, which can be organized and adjusted in their spacing by means of the upper Teflon separator (1 1) or the larger upper Teflon separator (12). said spacing of the seals allows anchoring and a seal of the mandrel pocket. Additionally, this upper spacer (9) is connected with an upper box thread of 28.575 mm to the lower part of the injection sub (2) and with a lower external pin thread of 25.4 mm it is connected to the lower spacer (15).

7. The downhole corrosion and scaling measurement system for injection wells of claim 1, characterized in that the lower spacer (15) has a 0.375NC internal box concentric thread that allows the coupling of the lower coupon holder (13) by means of a 0.375NC pin thread (13A), remaining centered and supported; and this lower coupon (14) consists of a sheet (14A) and two holes (14B and 14C) that allow it to be secured to the lower coupon holder (13) avoiding metal-to-metal contact; and said lower spacer (15), in its lower external part, has a diameter reduction to accommodate 10 unique lower packing seals (16) made of nitrile-kevlar, which can be organized and adjusted by means of a lower Teflon separator (17). This spacing of the seals allows anchoring and a more effective seal against the mandrel pocket.Where the lower spacer (15) is to accommodate the lower coupon holder (13) that holds the lower coupon (14) in such a way that it does not make contact with anything other than the return fluid.

8. The corrosion and scaling measurement system at the bottom of injection wells of claim 1, characterized in that the lower coupon holder (13) holds the coupon lower (14) by means of a system similar to that of the upper coupon (8), that is, by means of two lower segments (13C) that have threaded holes (13B) through which two continuous threaded studs (7) pass through, securing the coupon to the two lower segments. The nose (18) has an upper box thread of 28.575 mm, where the lower spacer (15) is connected. This nose has 10.922 mm holes in the lower part of it, which allow the entry of the return fluids from the well that will be in contact with the lower coupon (14) and thus achieve the evaluation of the corrosive or scaling phenomena caused by the interaction with these fluids.

9. The downhole corrosion and scaling measurement system for injection wells of claim 1, characterized in that the nose (18) has a design inside that allows the lower filter (19) to be housed, this filter has a circular shape and is housed in the lower internal part of the nose; the tip of the nose (18) has a hole to allow the passage of a 3.175 mm bronze pin (20) which is a redundant safety control device for the long tip (21). This long tip (21) has a 0.375NC thread on the upper part, which allows it to be coupled to the nose (18). This long tip allows the opening of the check valves of the injection mandrels.

10. The corrosion and scaling measurement system at the bottom of injection wells of claim 1, characterized in that it is constructed of stainless steel, designed for a linear assembly and has external seals with a configuration to reduce the risks of loosening and leaks.

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