System for Preventive Inhibition of Scaling in Oil Wells and Process for Preventive Inhibition of Scaling in Oil Wells

Abstract

A system(S) and process (P) for inhibiting scale in oil wells in reservoirs with a high risk of saline scale is described. Particularly, the system(S) comprises a plurality of components that have been configured and interconnected to embody the aforementioned process (P). The latter, in turn, encompasses a plurality of steps and features that provided, as one of the results achieved, the preventive profile for scale inhibition and also the gradual release of the scale inhibitor over a period of 2 to 3 years in oil wells with BSW less than or equal to 0.5%.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Brazilian Application No. BR1020240240790 filed on Nov. 19, 2024, the disclosure of which is expressly incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention pertains to the technical field of oil production processes and primary processing technologies. In particular, the present invention relates to a system and process for inhibiting scale in oil wells in reservoirs with a high risk of saline scale.BACKGROUND OF THE INVENTION

[0003] The scale formation in oil wells is a significant operational challenge for the oil and gas industry, directly impacting the efficiency and productivity of the extraction operations. The scales occur when dissolved salts and minerals, such as carbonates and sulfates, precipitate and adhere to the internal surfaces of pipes and equipment, restricting the fluid flow and compromising the system integrity. This process can result in production loss, increased maintenance costs, and, in extreme cases, the need to shut down operations to remove or replace the affected components.

[0004] The pressure and temperature conditions in oil wells, in addition to the chemical composition of the extracted fluids, are factors that favor the scale formation. Traditional methods of combating this problem, such as the injection of reactive chemicals (inhibitors, dispersants, and sequestrants) into the system, are often applied remedially, that is, only after deposits have formed. While these solutions can reduce or remove the scales that have already been formed, they do not prevent its recurrence and often require constant monitoring and repeated interventions, which generates high operating costs.

[0005] The preventive approach has gained prominence as a more efficient solution to the problem of the scales. Technologies that inhibit scale formation from the beginning of the extraction process are increasingly valued. These solutions involve the application of chemicals specially developed to bind to scale-forming ions, preventing them from precipitating and depositing on the internal surfaces of equipment. By continuously preventing the formation of solid deposits, these techniques extend equipment life, reduce maintenance downtime, and provide more economical and efficient operations.

[0006] The development of advanced preventive inhibition systems, adapted to the specific conditions of each oil well, is essential to ensure the economic viability of the extraction operations, especially in offshore environments, where the costs and complexity of the interventions are even greater.

[0007] Currently, there are no methods available on the market or in academia capable of preventing and / or controlling the scenario described above. To better understand the problems discussed herein, the state-of-the-art technologies that present these drawbacks will be described below.

[0008] The document FERREIRA D. R., “Estudo do aumento da eficiência do tratamento de inibição da incrustação a partir do aumento da razão liberação / retenção de inibidores na rocha-reservatório” (“Study of increasing the efficiency of the scale inhibition treatment by increasing the release / retention ratio of inhibitors in the reservoir rock”) 2015—Dissertation (Master's in Reservoir and Exploration Engineering)—Darcy Ribeiro State University of Northern Fluminense—discloses a methodology for improving adsorption, which is related only to corrective scale treatments. More specifically, the material published in this document of prior art is applied to squeeze inhibition during the reservoir production phase (well in operation) - this is a corrective application for this type of treatment. Furthermore, the improvement of the technology described herein does not apply to pre-salt reservoirs, mainly due to the exclusive use of the inhibitor diethylenetriamine pentamethylene phosphoric acid (DETPMP), which is a significantly limited application.

[0009] The document Jordan et al., “The Influence of Overflush Fluid Type on Scale Squeeze Life Time—Field Examples and Placement Simulation Evaluation,” 2008, in turn, discloses a one-step improvement in the squeeze (overflush) process. It is worth mentioning that the conventional squeeze process consists of the following steps:

[0010] Preflush: involves a solvent or solution capable of removing oily residues from the porous medium before the inhibitor enters. Examples of solvents include xylene, butyl glycol, and others;

[0011] Inhibitor cushion: comprises an aqueous solution containing a sufficient concentration to maintain the inhibitor mass incorporated into the porous medium and which will be produced after the treatment fluid is replaced by the produced aqueous fluid. Among the types of inhibitors that can be used are those based on phosphonates, phosphonate ethers, phosphate esters, polyacrylates, glucosides, etc.;

[0012] Aqueous overflush: This overflush moves the inhibitor cushion to the invasion zone, where maximum protection efficiency is achieved by incorporating the inhibitor into the porous medium. This cushion is generally made with potassium chloride (KCl) brine, desulfated water, or deionized (industrial) water.

[0013] Diesel or organic solvent overflush: aims at positioning the aqueous cushions in the reservoir rock and prevent water from starting up in the production string, thus avoiding hydrate formation in the production lines. The term “preventive” described in the abovementioned document of prior art refers to a proposed action on the impact of the preflush (the step prior to the squeeze, not a preventative treatment).

[0014] Regarding the inhibitor cushion, it consists of a treatment fluid, specifically a prepared water-based fluid. This inhibitor solution contains the scale inhibitor product, wherein its concentration must be greater than the minimum inhibition concentration up to 10% by volume of the treatment fluid. The produced water or the produced aqueous fluid is the water that originates in the reservoir and, after production from the surface well, is separated in the processing plant.

[0015] Document BR102021019813-3 describes a form of remote and autonomous inhibition treatment (without the use of a stimulation vessel) by offshore platforms, which, in this case, is performed after the scale formation. Therefore, said treatment is applied solely for remedial purposes.

[0016] The document Sitz et al., “Scale removal and inhibition in low-water cut wells,” Corrosion 2002, refers to methods of removing and inhibiting saline scale after the formation of inorganic solids (carbonates and sulfates) in the producing well during a remediation phase. Said document of prior art uses completion rigs (mechanical removal) to aid in both removal and inhibition. Additionally, the matter disclosed in this document of the state of the art relates to the application in wells with Basic Sediment and Water (BSW) content of less than 5%—in addition to this, the aforementioned document of prior art uses an original oil-based product, which constitutes a process involving significant environmental problems.

[0017] Thus, the technologies of the state of the art clearly present as problems the focus on saline scaling treatments of a solely corrective nature (which includes, for example, the use of stimulation vessels), mandatory preflush treatments (greater procedural complexity), the use of an organic overflush cushion (greater environmental impact), said use of an organic overflush cushion being also mandatory (greater procedural complexity) and the use of specific types of inhibitors (application restrictions, often directed solely to onshore). Furthermore, the technical drawbacks include the reduced useful life of the equipment and the minimization of downtime for maintenance. These undesirable features reflect the application of corrective processes.

[0018] Thus, the state of the art would clearly benefit from an inhibition process in oil wells, especially in reservoirs with a high risk of saline scaling. More specifically, the prior art would notably benefit from a preventive, simplified inhibition process with reduced environmental impact, and involving the use of inhibitors for pre-salt application, said inhibitors comprising a plurality of types. Furthermore, the simplicity of said process eliminates the need for stimulation vessels, extends the useful life of equipment, and reduces maintenance downtime.

[0019] Furthermore, the inhibition process in oil wells is also an alternative to the state of the art, that is, it presents distinct technical approaches, new to what already exists, and delivers efficient results, which may be similar to or better than those of related technologies.SUMMARY OF THE INVENTION

[0020] The proposed invention aims at solving the problem caused by the formation of severe inorganic scale located in the production string and equipment such as flow control valves (sliding sleeves and smart valves) in offshore oil-producing wells, which, however, due to operational issues or design limitations, lack facilities for continuous injection of the scale inhibitor or have limitations on the offshore production platform for performing treatments with the stimulation vessel (Well Stimulation Support Vessel—WSSV) and, consequently, may resort to costly rig operations to solve the scaling problem.

[0021] The solution achieved by the invention proposes a process for preventive inhibition of saline scaling, which consists of applying a scale inhibitor to the reservoir rock during well construction, completion, and maintenance operations. The inhibitor is gradually released over a period of 2 to 3 years in oil wells with BSW less than or equal to 0.5%. The preventive inhibition inhibits the formation of the saline scale in the reservoir-perforated section, well, and subsea lines until reaching the Stationary Production Unit (SPU). This initiative eliminates risks (such as operational risks related to workplace accidents or even the incomplete removal of the formed solid, resulting in loss of production and, consequently, expected revenue associated with the producing well in the company's strategic plan), costs with vessels and / or rigs, and reduces carbon dioxide emissions (zero carbon).

[0022] The present invention can be applied during oil well construction, completion, and maintenance operations, as well as in the management of pre-salt and post-salt reservoirs, flow assurance, and maintenance of the production systems such as the well, subsea production systems, and surface equipment.

[0023] The preventive inhibition is a highly efficient strategy that overcomes the operational difficulties associated with conventional remote treatments using stimulation vessels on offshore platforms or rigs. It involves the use of advance treatment methods during well construction, completion, and maintenance operations. An example is the Búzios field, which produces in ultra-deep waters and has been experiencing saline scale formation since the beginning of production, with the problem currently affecting 70% of the producing wells. The field of application encompasses reservoirs, lift, and flow, aiming to maintain the well production potential and ensure the functionality of well equipment.BRIEF DESCRIPTION OF THE DRAWING

[0024] In order to complement the present description and provide a better understanding of the features of the present invention, and in accordance with a preferred embodiment thereof, a set of figures is attached, exemplifying, but not limiting, its preferred embodiment.

[0025] FIG. 1 presents a schematic of the system(S) for inhibiting scale in oil wells, which is the object of the present invention.DETAILED DESCRIPTION OF THE INVENTION

[0026] The process for inhibiting scale in oil wells, in accordance with a preferred embodiment of the present invention, is described in detail below, based on the attached figures.

[0027] It should be understood that the term “preflush” as previously mentioned will hereinafter be referred to as “preflush.”

[0028] It should be understood that the term “overflush” as previously mentioned will hereinafter be referred to as “overflush.”

[0029] It should be understood that the term “workover” as previously mentioned will hereinafter be referred to as “well maintenance with a rig.”

[0030] It should be understood that the term “squeeze” as previously mentioned is a term for which there is no equivalent word in Portuguese in the oil industry. Accordingly, it will be maintained throughout the present specification and in the attached set of claims.

[0031] It should be understood that the term “sliding sleeves” as previously mentioned will hereinafter be referred to as “sliding sleeve valve.”

[0032] It should be understood that the term “Well Stimulation Support Vessel” as previously mentioned will hereinafter be referred to as “stimulation vessel.”

[0033] It should be understood that the term “Drillpipe riser,” frequently used in the oil industry, will hereinafter be referred to as “drilling string.”

[0034] In a first aspect, the present invention relates to a SYSTEM(S) FOR PREVENTIVE INHIBITION OF SCALING IN OIL WELLS, said system(S) comprising the following components and interconnections:

[0035] a stimulation vessel (4) interconnected to a completion rig (6);

[0036] a drilling string (9) interconnected at the top with the rig (6), and interconnected at the bottom with a production string (11); and

[0037] a reservoir rock (13) that externally surrounds the production string (11).

[0038] In a non-restrictive embodiment of the present invention, the interconnection of the vessel (4) with the rig (6) occurs by means of a transfer pipe (5) directly connected to connection lines (7) present in said rig (6), wherein said lines (7) are consecutively connected to a circulation head (8) that is also present in said rig (6).

[0039] In a non-restrictive embodiment of the present invention, the interconnection of the drilling string (9) with the rig (6) occurs by means of the circulation head (8).

[0040] In a non-restrictive embodiment of the present invention, the interconnection of the drilling string (9) with the production string (11) occurs by means of a wet Christmas tree (WCT) (10), wherein said production string (11) comprises selective completion valves (12).

[0041] In a non-restrictive embodiment of the present invention, the stimulation vessel (4) comprises a tank (1) for storing a scale inhibitor, a tank (2) for industrial water or a saline fluid, and a tank (3) for preparing an inhibitor solution, wherein the tank (3) has interconnection with the tanks (1) and (2).

[0042] In a second aspect, the present invention relates to a PROCESS (P) FOR PREVENTIVE INHIBITION OF SCALING IN OIL WELLS, said process (P) occurring in the system(S) for preventively inhibiting scale in oil wells, said process (P) comprising the following steps:

[0043] step 1: transfer of the scale inhibitor, initially contained in the tank (1), to the tank (3); and transfer of industrial water or saline fluid, initially contained in the tank (2), to the tank (3);

[0044] step 2: preparation of the inhibitor solution in the tank (3);

[0045] step 3: interconnection of the vessel (4) with the rig (6);

[0046] step 4: interconnection of the components in the rig (6) by means of the pipe (5), connection lines (7), and circulation head (8);

[0047] step 5: maneuvering the WCT (10) and valves (12) to align the treatment with the reservoir rock (13);

[0048] step 6: pumping the inhibitor solution from the vessel (4) to the rig (6) through the tubing (5), followed by pumping said solution to the production string (11) through the drilling string (9); and

[0049] step 7: maneuvering the valves (12) to pump the inhibitor solution.

[0050] In a non-restrictive embodiment of the present invention, the process (P) optionally comprises the following steps:

[0051] step 8: conditioning the reservoir rock (13) after pumping is completed in step 7;

[0052] step 9: action of the inhibitor solution in the reservoir (soaking); and

[0053] step 10: preparing the reservoir rock (13) for opening and production.

[0054] In a non-restrictive embodiment of the present invention, in step 2, the preparation of the inhibitor solution comprises the use of 5,000 liters of the scale inhibitor from the tank (1), and the use of 245,000 liters of water or use of 245,000 liters of saline fluid, wherein the saline fluid, when chosen to be used in the tank (2), is an aqueous solution of potassium chloride at a concentration of 2 to 3% m / V. As noted, the volume of inhibitor solution in the tank (3) is 250,000 liters, with 5,000 liters coming from the tank (2) and 245,000 liters coming from the tank (3).

[0055] In a non-restrictive embodiment of the present invention, the scale inhibitor is a chemical formulation comprising a scale inhibitor selected from the group comprising phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides, wherein said scale inhibitor is present in said chemical formulation at a concentration between 10% and 50% w / V.

[0056] The examples of embodiments of the present invention will be described below. However, it should be understood that such a description is disclosed herein for the purpose of better understanding by a technician skilled on the subject, without, however, restricting the scope of protection defined in the attached claims.EXAMPLE 1Description of the System(s) of the Present Invention

[0057] The process (P) for preventive inhibition of scaling in oil wells, which is the object of the present invention, preferably occurs in a system(S) for preventive inhibition of scaling in oil wells. For better understanding, the system(S) can also be visualized in FIG. 1, which shows the main components of said system(S), namely:

[0058] (1) scale inhibitor storage tank;

[0059] (2) industrial water or saline fluid tank;

[0060] (3) fluid preparation tank for the stimulation vessel;

[0061] (4) stimulation vessel;

[0062] (5) transfer pipe (coflexip) between the vessel (4) and the completion rig (6);

[0063] (6) completion rig;

[0064] (7) circulation circuit connection lines;

[0065] (8) circulation head;

[0066] (9) drilling string;

[0067] (10) wet Christmas tree (WCT);

[0068] (11) production string;

[0069] (12) selective completion valves; and

[0070] (13) reservoir rock.EXAMPLE 2Description of the Preferred Embodiment of the Process (P) for Preventive Scale Inhibition in Oil Wells

[0071] Considering the system(S) described in the previous example, it is possible to understand the preferred embodiment of the process (P) and its interconnection with the system (S). In this way, the process (P) comprises the following steps:

[0072] step 1: transfer of the scale inhibitor, initially contained in the tank (1), to the tank (3); and transfer of industrial water (or saline fluid), initially contained in the tank (2), to the tank (3);

[0073] step 2: preparation of the inhibitor solution in the tank (3) contained in the vessel (4);

[0074] step 3: interconnection of the vessel (4) with the rig (6);

[0075] step 4: interconnection of the components in the rig (6) by means of the pipe (5), connection lines (7), and circulation head (8);

[0076] step 5: maneuvering the WCT (10) and valves (12) to align the treatment with the reservoir rock (13);

[0077] step 6: pumping the inhibitor solution from the vessel (4) to the rig (6) through the tubing (5), followed by pumping said solution to the production string (11) through the drilling string (9);

[0078] step 7: maneuvering the valves (12) to pump the inhibitor solution;

[0079] step 8: conditioning the reservoir rock (13) after pumping is completed;

[0080] step 9: action of the inhibitor solution in the reservoir (soaking); and

[0081] step 10: preparing the reservoir rock for opening and production.

[0082] Each of the above steps is described in details below.

[0083] Step 1: A tank (1) is requested from the product supplier (scale inhibitor) (usually 5,000 liters) for logistical treatment for delivery to the rig; and transfer from the tank (1) to the vessel (4).

[0084] Step 2: After transferring the tank (1) to the vessel (4), the contents of the tank (1) are transferred to the preparation tank (3), which receives the industrial water or saline fluid contained in the tank (2) to prepare the inhibitor solution (alternatively referred to as treatment fluid) in the tank (3), which is stored in the tank (3) itself. The volume of water or saline fluid in the tank (2), used to dilute the scale inhibitor in the tank (3), is 245,000 liters. Within this volume of 245,000 liters of water or saline fluid, the use of additives such as butyl glycol or a demulsifier is permitted, and only optionally.

[0085] Step 3: To transfer the inhibitor solution from the tank (3) to the rig (6), the tubing (5) with a coating tolerant to the inhibitor solution (3) and an injection pump are used to collect said solution from the tank (3) and transfer it to the connection lines (7) and circulation head (8).

[0086] Step 4: The platform operators of the rig (6) assemble and connect the connection lines (7) to the circulation head (8) to allow the transfer of the inhibitor solution from the tank (3) through the tubing (5).

[0087] Step 5: The platform operators of the rig (6), using the control of the WCT (10), maneuver the valves of the WCT (10) to align the injection of the inhibitor solution to the drilling string (9).

[0088] Step 6: The inhibitor solution contained in the tank (3) is injected into the reservoir rock (13) as follows: pumping said solution through the tubing (5), the connection lines (7), and the circulation head (8), next following to the drilling string (9), passing through the WCT (10), the production string (11), and the valves (12), for injection into the reservoir rock (13).

[0089] Step 7: The injection can occur selectively when the valves (12) are maneuvered by injecting the inhibitor solution (treatment fluid) between different zones of the reservoir rock (13).

[0090] It is worth mentioning that steps 1 to 7 are essential in the present invention. On the other hand, the valves (12) can be dispensed with some treatments if they are inoperative (injection without selectivity).

[0091] Step 8: Conditioning is generally performed by injecting dehydrated diesel fuel to allow the reservoir rock (13) to be ready for the production unit after the intervention with the rig (6) is completed, leaving the production line and production string (11) conditioned with diesel fuel, ready for the reservoir rock (13) to be started.

[0092] Step 9: The inhibitor solution (treatment fluid) must remain in contact with the reservoir rock (13) for several hours (24 hours are recommended) to allow the maximum incorporation of inhibitor mass into the rock and the best inhibition performance after resumption of the production.

[0093] Step 10: Preparation of the reservoir rock (13) for opening and production. After the inhibitor solution has finished acting on the reservoir rock (13), the WCT (10) and valves (12) are maneuvered to allow the safe opening and production between the reservoir rock (13) and the production string (11).

[0094] Considering the essence of the present invention, its main objective is the early treatment of oil-producing wells that present difficulties in injecting a scale inhibitor (e.g., lack of facilities or devices), without the need to negotiate production losses that generally lead to a depreciation of the value of the inhibition operation.

[0095] It should be noted that the scale inhibitor contained in the tank (1) is a chemical formulation. This formulation preferably comprises phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides. It is important to note, for the sake of completeness, that the scale inhibitor to be used in the tank (1) is often commercially available as a trade secret, both in terms of the chemical nature of the inhibitor (phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides) and its concentration in the formulation, which can vary from 10% to 50% m / V, depending on the qualified substance. This concentration range is defined in laboratory tests for rock compatibility and inhibition efficiency. In addition, any information regarding the presence or absence of excipients (surfactants, dispersants, thickeners, etc.) in this chemical formulation (referred herein as the “scale inhibitor” in this invention) is also omitted. Therefore, for a technician skilled on the subject to accurately reproduce the present invention, a commercially available scale inhibitor duly qualified for rock formations and applicable to any form of saline scale must be used. In fact, it is preferred to use a product that describes at least the presence of phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides. However, this is not mandatory information; as mentioned, describing the product as being suitable for removing carbonate scale is sufficient. The same applies to the optional additives to be added to the water or saline fluid fed to the tank (2), as these additives are also generally marketed as a trade secret.

[0096] Essentially, and when chosen for use in the tank (2), the saline fluid is a potassium chloride solution at a concentration of 2 to 3% m / V, wherein the remainder of the composition can be water (preferably) or water with said additives, at any concentration.

[0097] As can be seen and as already previously discussed, the preventive inhibition process in oil wells, which is the object of the present invention, utilizes resources from the well completion phase (or well maintenance with a rig) pre-planned before the well starts or resumes operation in the offshore unit. More specifically, the present invention takes advantage of the facilities available in stimulation during the well completion phase or during maintenance.

[0098] Furthermore, and as noted, the process described in the present example of embodiment uses water-based products, resulting in a reduced environmental impact, a recurring technical problem in technologies of the state of the art. In addition, such products are compatible with other additives, such as demulsifiers, biocides, organic acids, inorganic acids, and other related additives.

[0099] Finally, it is also crystal clear that, in the process described herein, which is the object of the present invention, the inhibitor is not restricted to a single type, as is often the case in currently existing technologies.EXAMPLE 3Results

[0100] In the present invention, the process (P) and its interconnection with the system(S) allowed the gradual release of the scale inhibitor over a period of 2 to 3 years in oil wells with BSW less than or equal to 0.5%. Consequently, such a result allows for the postponement of scale removal operations, which subject the producing wells to production loss due to scale, difficulty in planning joint removal and inhibition operations, and the possible use of a rig and WSSV in operations outside the field management prediction, which impact these resources considered critical.

[0101] Those skilled in the art will value the knowledge presented herein and will be able to reproduce the invention in the presented embodiments and in other variations encompassed by the scope of the attached claims.

Examples

example 1

Description of the System(s) of the Present Invention

[0057]The process (P) for preventive inhibition of scaling in oil wells, which is the object of the present invention, preferably occurs in a system(S) for preventive inhibition of scaling in oil wells. For better understanding, the system(S) can also be visualized in FIG. 1, which shows the main components of said system(S), namely:[0058](1) scale inhibitor storage tank;[0059](2) industrial water or saline fluid tank;[0060](3) fluid preparation tank for the stimulation vessel;[0061](4) stimulation vessel;[0062](5) transfer pipe (coflexip) between the vessel (4) and the completion rig (6);[0063](6) completion rig;[0064](7) circulation circuit connection lines;[0065](8) circulation head;[0066](9) drilling string;[0067](10) wet Christmas tree (WCT);[0068](11) production string;[0069](12) selective completion valves; and[0070](13) reservoir rock.

example 2

Description of the Preferred Embodiment of the Process (P) for Preventive Scale Inhibition in Oil Wells

[0071]Considering the system(S) described in the previous example, it is possible to understand the preferred embodiment of the process (P) and its interconnection with the system (S). In this way, the process (P) comprises the following steps:[0072]step 1: transfer of the scale inhibitor, initially contained in the tank (1), to the tank (3); and transfer of industrial water (or saline fluid), initially contained in the tank (2), to the tank (3);[0073]step 2: preparation of the inhibitor solution in the tank (3) contained in the vessel (4);[0074]step 3: interconnection of the vessel (4) with the rig (6);[0075]step 4: interconnection of the components in the rig (6) by means of the pipe (5), connection lines (7), and circulation head (8);[0076]step 5: maneuvering the WCT (10) and valves (12) to align the treatment with the reservoir rock (13);[0077]step 6: pumping the inhibitor solu...

example 3

Results

[0100]In the present invention, the process (P) and its interconnection with the system(S) allowed the gradual release of the scale inhibitor over a period of 2 to 3 years in oil wells with BSW less than or equal to 0.5%. Consequently, such a result allows for the postponement of scale removal operations, which subject the producing wells to production loss due to scale, difficulty in planning joint removal and inhibition operations, and the possible use of a rig and WSSV in operations outside the field management prediction, which impact these resources considered critical.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Brazilian Application No. BR1020240240790 filed on Nov. 19, 2024, the disclosure of which is expressly incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention pertains to the technical field of oil production processes and primary processing technologies. In particular, the present invention relates to a system and process for inhibiting scale in oil wells in reservoirs with a high risk of saline scale.BACKGROUND OF THE INVENTION

[0003] The scale formation in oil wells is a significant operational challenge for the oil and gas industry, directly impacting the efficiency and productivity of the extraction operations. The scales occur when dissolved salts and minerals, such as carbonates and sulfates, precipitate and adhere to the internal surfaces of pipes and equipment, restricting the fluid flow and compromising the system integrity. This process can result in production loss, increased maintenance costs, and, in extreme cases, the need to shut down operations to remove or replace the affected components.

[0004] The pressure and temperature conditions in oil wells, in addition to the chemical composition of the extracted fluids, are factors that favor the scale formation. Traditional methods of combating this problem, such as the injection of reactive chemicals (inhibitors, dispersants, and sequestrants) into the system, are often applied remedially, that is, only after deposits have formed. While these solutions can reduce or remove the scales that have already been formed, they do not prevent its recurrence and often require constant monitoring and repeated interventions, which generates high operating costs.

[0005] The preventive approach has gained prominence as a more efficient solution to the problem of the scales. Technologies that inhibit scale formation from the beginning of the extraction process are increasingly valued. These solutions involve the application of chemicals specially developed to bind to scale-forming ions, preventing them from precipitating and depositing on the internal surfaces of equipment. By continuously preventing the formation of solid deposits, these techniques extend equipment life, reduce maintenance downtime, and provide more economical and efficient operations.

[0006] The development of advanced preventive inhibition systems, adapted to the specific conditions of each oil well, is essential to ensure the economic viability of the extraction operations, especially in offshore environments, where the costs and complexity of the interventions are even greater.

[0007] Currently, there are no methods available on the market or in academia capable of preventing and / or controlling the scenario described above. To better understand the problems discussed herein, the state-of-the-art technologies that present these drawbacks will be described below.

[0008] The document FERREIRA D. R., “Estudo do aumento da eficiência do tratamento de inibição da incrustação a partir do aumento da razão liberação / retenção de inibidores na rocha-reservatório” (“Study of increasing the efficiency of the scale inhibition treatment by increasing the release / retention ratio of inhibitors in the reservoir rock”) 2015—Dissertation (Master's in Reservoir and Exploration Engineering)—Darcy Ribeiro State University of Northern Fluminense—discloses a methodology for improving adsorption, which is related only to corrective scale treatments. More specifically, the material published in this document of prior art is applied to squeeze inhibition during the reservoir production phase (well in operation) - this is a corrective application for this type of treatment. Furthermore, the improvement of the technology described herein does not apply to pre-salt reservoirs, mainly due to the exclusive use of the inhibitor diethylenetriamine pentamethylene phosphoric acid (DETPMP), which is a significantly limited application.

[0009] The document Jordan et al., “The Influence of Overflush Fluid Type on Scale Squeeze Life Time—Field Examples and Placement Simulation Evaluation,” 2008, in turn, discloses a one-step improvement in the squeeze (overflush) process. It is worth mentioning that the conventional squeeze process consists of the following steps:

[0010] Preflush: involves a solvent or solution capable of removing oily residues from the porous medium before the inhibitor enters. Examples of solvents include xylene, butyl glycol, and others;

[0011] Inhibitor cushion: comprises an aqueous solution containing a sufficient concentration to maintain the inhibitor mass incorporated into the porous medium and which will be produced after the treatment fluid is replaced by the produced aqueous fluid. Among the types of inhibitors that can be used are those based on phosphonates, phosphonate ethers, phosphate esters, polyacrylates, glucosides, etc.;

[0012] Aqueous overflush: This overflush moves the inhibitor cushion to the invasion zone, where maximum protection efficiency is achieved by incorporating the inhibitor into the porous medium. This cushion is generally made with potassium chloride (KCl) brine, desulfated water, or deionized (industrial) water.

[0013] Diesel or organic solvent overflush: aims at positioning the aqueous cushions in the reservoir rock and prevent water from starting up in the production string, thus avoiding hydrate formation in the production lines. The term “preventive” described in the abovementioned document of prior art refers to a proposed action on the impact of the preflush (the step prior to the squeeze, not a preventative treatment).

[0014] Regarding the inhibitor cushion, it consists of a treatment fluid, specifically a prepared water-based fluid. This inhibitor solution contains the scale inhibitor product, wherein its concentration must be greater than the minimum inhibition concentration up to 10% by volume of the treatment fluid. The produced water or the produced aqueous fluid is the water that originates in the reservoir and, after production from the surface well, is separated in the processing plant.

[0015] Document BR102021019813-3 describes a form of remote and autonomous inhibition treatment (without the use of a stimulation vessel) by offshore platforms, which, in this case, is performed after the scale formation. Therefore, said treatment is applied solely for remedial purposes.

[0016] The document Sitz et al., “Scale removal and inhibition in low-water cut wells,” Corrosion 2002, refers to methods of removing and inhibiting saline scale after the formation of inorganic solids (carbonates and sulfates) in the producing well during a remediation phase. Said document of prior art uses completion rigs (mechanical removal) to aid in both removal and inhibition. Additionally, the matter disclosed in this document of the state of the art relates to the application in wells with Basic Sediment and Water (BSW) content of less than 5%—in addition to this, the aforementioned document of prior art uses an original oil-based product, which constitutes a process involving significant environmental problems.

[0017] Thus, the technologies of the state of the art clearly present as problems the focus on saline scaling treatments of a solely corrective nature (which includes, for example, the use of stimulation vessels), mandatory preflush treatments (greater procedural complexity), the use of an organic overflush cushion (greater environmental impact), said use of an organic overflush cushion being also mandatory (greater procedural complexity) and the use of specific types of inhibitors (application restrictions, often directed solely to onshore). Furthermore, the technical drawbacks include the reduced useful life of the equipment and the minimization of downtime for maintenance. These undesirable features reflect the application of corrective processes.

[0018] Thus, the state of the art would clearly benefit from an inhibition process in oil wells, especially in reservoirs with a high risk of saline scaling. More specifically, the prior art would notably benefit from a preventive, simplified inhibition process with reduced environmental impact, and involving the use of inhibitors for pre-salt application, said inhibitors comprising a plurality of types. Furthermore, the simplicity of said process eliminates the need for stimulation vessels, extends the useful life of equipment, and reduces maintenance downtime.

[0019] Furthermore, the inhibition process in oil wells is also an alternative to the state of the art, that is, it presents distinct technical approaches, new to what already exists, and delivers efficient results, which may be similar to or better than those of related technologies.SUMMARY OF THE INVENTION

[0020] The proposed invention aims at solving the problem caused by the formation of severe inorganic scale located in the production string and equipment such as flow control valves (sliding sleeves and smart valves) in offshore oil-producing wells, which, however, due to operational issues or design limitations, lack facilities for continuous injection of the scale inhibitor or have limitations on the offshore production platform for performing treatments with the stimulation vessel (Well Stimulation Support Vessel—WSSV) and, consequently, may resort to costly rig operations to solve the scaling problem.

[0021] The solution achieved by the invention proposes a process for preventive inhibition of saline scaling, which consists of applying a scale inhibitor to the reservoir rock during well construction, completion, and maintenance operations. The inhibitor is gradually released over a period of 2 to 3 years in oil wells with BSW less than or equal to 0.5%. The preventive inhibition inhibits the formation of the saline scale in the reservoir-perforated section, well, and subsea lines until reaching the Stationary Production Unit (SPU). This initiative eliminates risks (such as operational risks related to workplace accidents or even the incomplete removal of the formed solid, resulting in loss of production and, consequently, expected revenue associated with the producing well in the company's strategic plan), costs with vessels and / or rigs, and reduces carbon dioxide emissions (zero carbon).

[0022] The present invention can be applied during oil well construction, completion, and maintenance operations, as well as in the management of pre-salt and post-salt reservoirs, flow assurance, and maintenance of the production systems such as the well, subsea production systems, and surface equipment.

[0023] The preventive inhibition is a highly efficient strategy that overcomes the operational difficulties associated with conventional remote treatments using stimulation vessels on offshore platforms or rigs. It involves the use of advance treatment methods during well construction, completion, and maintenance operations. An example is the Búzios field, which produces in ultra-deep waters and has been experiencing saline scale formation since the beginning of production, with the problem currently affecting 70% of the producing wells. The field of application encompasses reservoirs, lift, and flow, aiming to maintain the well production potential and ensure the functionality of well equipment.BRIEF DESCRIPTION OF THE DRAWING

[0024] In order to complement the present description and provide a better understanding of the features of the present invention, and in accordance with a preferred embodiment thereof, a set of figures is attached, exemplifying, but not limiting, its preferred embodiment.

[0025] FIG. 1 presents a schematic of the system(S) for inhibiting scale in oil wells, which is the object of the present invention.DETAILED DESCRIPTION OF THE INVENTION

[0026] The process for inhibiting scale in oil wells, in accordance with a preferred embodiment of the present invention, is described in detail below, based on the attached figures.

[0027] It should be understood that the term “preflush” as previously mentioned will hereinafter be referred to as “preflush.”

[0028] It should be understood that the term “overflush” as previously mentioned will hereinafter be referred to as “overflush.”

[0029] It should be understood that the term “workover” as previously mentioned will hereinafter be referred to as “well maintenance with a rig.”

[0030] It should be understood that the term “squeeze” as previously mentioned is a term for which there is no equivalent word in Portuguese in the oil industry. Accordingly, it will be maintained throughout the present specification and in the attached set of claims.

[0031] It should be understood that the term “sliding sleeves” as previously mentioned will hereinafter be referred to as “sliding sleeve valve.”

[0032] It should be understood that the term “Well Stimulation Support Vessel” as previously mentioned will hereinafter be referred to as “stimulation vessel.”

[0033] It should be understood that the term “Drillpipe riser,” frequently used in the oil industry, will hereinafter be referred to as “drilling string.”

[0034] In a first aspect, the present invention relates to a SYSTEM(S) FOR PREVENTIVE INHIBITION OF SCALING IN OIL WELLS, said system(S) comprising the following components and interconnections:

[0035] a stimulation vessel (4) interconnected to a completion rig (6);

[0036] a drilling string (9) interconnected at the top with the rig (6), and interconnected at the bottom with a production string (11); and

[0037] a reservoir rock (13) that externally surrounds the production string (11).

[0038] In a non-restrictive embodiment of the present invention, the interconnection of the vessel (4) with the rig (6) occurs by means of a transfer pipe (5) directly connected to connection lines (7) present in said rig (6), wherein said lines (7) are consecutively connected to a circulation head (8) that is also present in said rig (6).

[0039] In a non-restrictive embodiment of the present invention, the interconnection of the drilling string (9) with the rig (6) occurs by means of the circulation head (8).

[0040] In a non-restrictive embodiment of the present invention, the interconnection of the drilling string (9) with the production string (11) occurs by means of a wet Christmas tree (WCT) (10), wherein said production string (11) comprises selective completion valves (12).

[0041] In a non-restrictive embodiment of the present invention, the stimulation vessel (4) comprises a tank (1) for storing a scale inhibitor, a tank (2) for industrial water or a saline fluid, and a tank (3) for preparing an inhibitor solution, wherein the tank (3) has interconnection with the tanks (1) and (2).

[0042] In a second aspect, the present invention relates to a PROCESS (P) FOR PREVENTIVE INHIBITION OF SCALING IN OIL WELLS, said process (P) occurring in the system(S) for preventively inhibiting scale in oil wells, said process (P) comprising the following steps:

[0043] step 1: transfer of the scale inhibitor, initially contained in the tank (1), to the tank (3); and transfer of industrial water or saline fluid, initially contained in the tank (2), to the tank (3);

[0044] step 2: preparation of the inhibitor solution in the tank (3);

[0045] step 3: interconnection of the vessel (4) with the rig (6);

[0046] step 4: interconnection of the components in the rig (6) by means of the pipe (5), connection lines (7), and circulation head (8);

[0047] step 5: maneuvering the WCT (10) and valves (12) to align the treatment with the reservoir rock (13);

[0048] step 6: pumping the inhibitor solution from the vessel (4) to the rig (6) through the tubing (5), followed by pumping said solution to the production string (11) through the drilling string (9); and

[0049] step 7: maneuvering the valves (12) to pump the inhibitor solution.

[0050] In a non-restrictive embodiment of the present invention, the process (P) optionally comprises the following steps:

[0051] step 8: conditioning the reservoir rock (13) after pumping is completed in step 7;

[0052] step 9: action of the inhibitor solution in the reservoir (soaking); and

[0053] step 10: preparing the reservoir rock (13) for opening and production.

[0054] In a non-restrictive embodiment of the present invention, in step 2, the preparation of the inhibitor solution comprises the use of 5,000 liters of the scale inhibitor from the tank (1), and the use of 245,000 liters of water or use of 245,000 liters of saline fluid, wherein the saline fluid, when chosen to be used in the tank (2), is an aqueous solution of potassium chloride at a concentration of 2 to 3% m / V. As noted, the volume of inhibitor solution in the tank (3) is 250,000 liters, with 5,000 liters coming from the tank (2) and 245,000 liters coming from the tank (3).

[0055] In a non-restrictive embodiment of the present invention, the scale inhibitor is a chemical formulation comprising a scale inhibitor selected from the group comprising phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides, wherein said scale inhibitor is present in said chemical formulation at a concentration between 10% and 50% w / V.

[0056] The examples of embodiments of the present invention will be described below. However, it should be understood that such a description is disclosed herein for the purpose of better understanding by a technician skilled on the subject, without, however, restricting the scope of protection defined in the attached claims.EXAMPLE 1Description of the System(s) of the Present Invention

[0057] The process (P) for preventive inhibition of scaling in oil wells, which is the object of the present invention, preferably occurs in a system(S) for preventive inhibition of scaling in oil wells. For better understanding, the system(S) can also be visualized in FIG. 1, which shows the main components of said system(S), namely:

[0058] (1) scale inhibitor storage tank;

[0059] (2) industrial water or saline fluid tank;

[0060] (3) fluid preparation tank for the stimulation vessel;

[0061] (4) stimulation vessel;

[0062] (5) transfer pipe (coflexip) between the vessel (4) and the completion rig (6);

[0063] (6) completion rig;

[0064] (7) circulation circuit connection lines;

[0065] (8) circulation head;

[0066] (9) drilling string;

[0067] (10) wet Christmas tree (WCT);

[0068] (11) production string;

[0069] (12) selective completion valves; and

[0070] (13) reservoir rock.EXAMPLE 2Description of the Preferred Embodiment of the Process (P) for Preventive Scale Inhibition in Oil Wells

[0071] Considering the system(S) described in the previous example, it is possible to understand the preferred embodiment of the process (P) and its interconnection with the system (S). In this way, the process (P) comprises the following steps:

[0072] step 1: transfer of the scale inhibitor, initially contained in the tank (1), to the tank (3); and transfer of industrial water (or saline fluid), initially contained in the tank (2), to the tank (3);

[0073] step 2: preparation of the inhibitor solution in the tank (3) contained in the vessel (4);

[0074] step 3: interconnection of the vessel (4) with the rig (6);

[0075] step 4: interconnection of the components in the rig (6) by means of the pipe (5), connection lines (7), and circulation head (8);

[0076] step 5: maneuvering the WCT (10) and valves (12) to align the treatment with the reservoir rock (13);

[0077] step 6: pumping the inhibitor solution from the vessel (4) to the rig (6) through the tubing (5), followed by pumping said solution to the production string (11) through the drilling string (9);

[0078] step 7: maneuvering the valves (12) to pump the inhibitor solution;

[0079] step 8: conditioning the reservoir rock (13) after pumping is completed;

[0080] step 9: action of the inhibitor solution in the reservoir (soaking); and

[0081] step 10: preparing the reservoir rock for opening and production.

[0082] Each of the above steps is described in details below.

[0083] Step 1: A tank (1) is requested from the product supplier (scale inhibitor) (usually 5,000 liters) for logistical treatment for delivery to the rig; and transfer from the tank (1) to the vessel (4).

[0084] Step 2: After transferring the tank (1) to the vessel (4), the contents of the tank (1) are transferred to the preparation tank (3), which receives the industrial water or saline fluid contained in the tank (2) to prepare the inhibitor solution (alternatively referred to as treatment fluid) in the tank (3), which is stored in the tank (3) itself. The volume of water or saline fluid in the tank (2), used to dilute the scale inhibitor in the tank (3), is 245,000 liters. Within this volume of 245,000 liters of water or saline fluid, the use of additives such as butyl glycol or a demulsifier is permitted, and only optionally.

[0085] Step 3: To transfer the inhibitor solution from the tank (3) to the rig (6), the tubing (5) with a coating tolerant to the inhibitor solution (3) and an injection pump are used to collect said solution from the tank (3) and transfer it to the connection lines (7) and circulation head (8).

[0086] Step 4: The platform operators of the rig (6) assemble and connect the connection lines (7) to the circulation head (8) to allow the transfer of the inhibitor solution from the tank (3) through the tubing (5).

[0087] Step 5: The platform operators of the rig (6), using the control of the WCT (10), maneuver the valves of the WCT (10) to align the injection of the inhibitor solution to the drilling string (9).

[0088] Step 6: The inhibitor solution contained in the tank (3) is injected into the reservoir rock (13) as follows: pumping said solution through the tubing (5), the connection lines (7), and the circulation head (8), next following to the drilling string (9), passing through the WCT (10), the production string (11), and the valves (12), for injection into the reservoir rock (13).

[0089] Step 7: The injection can occur selectively when the valves (12) are maneuvered by injecting the inhibitor solution (treatment fluid) between different zones of the reservoir rock (13).

[0090] It is worth mentioning that steps 1 to 7 are essential in the present invention. On the other hand, the valves (12) can be dispensed with some treatments if they are inoperative (injection without selectivity).

[0091] Step 8: Conditioning is generally performed by injecting dehydrated diesel fuel to allow the reservoir rock (13) to be ready for the production unit after the intervention with the rig (6) is completed, leaving the production line and production string (11) conditioned with diesel fuel, ready for the reservoir rock (13) to be started.

[0092] Step 9: The inhibitor solution (treatment fluid) must remain in contact with the reservoir rock (13) for several hours (24 hours are recommended) to allow the maximum incorporation of inhibitor mass into the rock and the best inhibition performance after resumption of the production.

[0093] Step 10: Preparation of the reservoir rock (13) for opening and production. After the inhibitor solution has finished acting on the reservoir rock (13), the WCT (10) and valves (12) are maneuvered to allow the safe opening and production between the reservoir rock (13) and the production string (11).

[0094] Considering the essence of the present invention, its main objective is the early treatment of oil-producing wells that present difficulties in injecting a scale inhibitor (e.g., lack of facilities or devices), without the need to negotiate production losses that generally lead to a depreciation of the value of the inhibition operation.

[0095] It should be noted that the scale inhibitor contained in the tank (1) is a chemical formulation. This formulation preferably comprises phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides. It is important to note, for the sake of completeness, that the scale inhibitor to be used in the tank (1) is often commercially available as a trade secret, both in terms of the chemical nature of the inhibitor (phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides) and its concentration in the formulation, which can vary from 10% to 50% m / V, depending on the qualified substance. This concentration range is defined in laboratory tests for rock compatibility and inhibition efficiency. In addition, any information regarding the presence or absence of excipients (surfactants, dispersants, thickeners, etc.) in this chemical formulation (referred herein as the “scale inhibitor” in this invention) is also omitted. Therefore, for a technician skilled on the subject to accurately reproduce the present invention, a commercially available scale inhibitor duly qualified for rock formations and applicable to any form of saline scale must be used. In fact, it is preferred to use a product that describes at least the presence of phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides. However, this is not mandatory information; as mentioned, describing the product as being suitable for removing carbonate scale is sufficient. The same applies to the optional additives to be added to the water or saline fluid fed to the tank (2), as these additives are also generally marketed as a trade secret.

[0096] Essentially, and when chosen for use in the tank (2), the saline fluid is a potassium chloride solution at a concentration of 2 to 3% m / V, wherein the remainder of the composition can be water (preferably) or water with said additives, at any concentration.

[0097] As can be seen and as already previously discussed, the preventive inhibition process in oil wells, which is the object of the present invention, utilizes resources from the well completion phase (or well maintenance with a rig) pre-planned before the well starts or resumes operation in the offshore unit. More specifically, the present invention takes advantage of the facilities available in stimulation during the well completion phase or during maintenance.

[0098] Furthermore, and as noted, the process described in the present example of embodiment uses water-based products, resulting in a reduced environmental impact, a recurring technical problem in technologies of the state of the art. In addition, such products are compatible with other additives, such as demulsifiers, biocides, organic acids, inorganic acids, and other related additives.

[0099] Finally, it is also crystal clear that, in the process described herein, which is the object of the present invention, the inhibitor is not restricted to a single type, as is often the case in currently existing technologies.EXAMPLE 3Results

[0100] In the present invention, the process (P) and its interconnection with the system(S) allowed the gradual release of the scale inhibitor over a period of 2 to 3 years in oil wells with BSW less than or equal to 0.5%. Consequently, such a result allows for the postponement of scale removal operations, which subject the producing wells to production loss due to scale, difficulty in planning joint removal and inhibition operations, and the possible use of a rig and WSSV in operations outside the field management prediction, which impact these resources considered critical.

[0101] Those skilled in the art will value the knowledge presented herein and will be able to reproduce the invention in the presented embodiments and in other variations encompassed by the scope of the attached claims.

Examples

example 1

Description of the System(s) of the Present Invention

[0057]The process (P) for preventive inhibition of scaling in oil wells, which is the object of the present invention, preferably occurs in a system(S) for preventive inhibition of scaling in oil wells. For better understanding, the system(S) can also be visualized in FIG. 1, which shows the main components of said system(S), namely:[0058](1) scale inhibitor storage tank;[0059](2) industrial water or saline fluid tank;[0060](3) fluid preparation tank for the stimulation vessel;[0061](4) stimulation vessel;[0062](5) transfer pipe (coflexip) between the vessel (4) and the completion rig (6);[0063](6) completion rig;[0064](7) circulation circuit connection lines;[0065](8) circulation head;[0066](9) drilling string;[0067](10) wet Christmas tree (WCT);[0068](11) production string;[0069](12) selective completion valves; and[0070](13) reservoir rock.

example 2

Description of the Preferred Embodiment of the Process (P) for Preventive Scale Inhibition in Oil Wells

[0071]Considering the system(S) described in the previous example, it is possible to understand the preferred embodiment of the process (P) and its interconnection with the system (S). In this way, the process (P) comprises the following steps:[0072]step 1: transfer of the scale inhibitor, initially contained in the tank (1), to the tank (3); and transfer of industrial water (or saline fluid), initially contained in the tank (2), to the tank (3);[0073]step 2: preparation of the inhibitor solution in the tank (3) contained in the vessel (4);[0074]step 3: interconnection of the vessel (4) with the rig (6);[0075]step 4: interconnection of the components in the rig (6) by means of the pipe (5), connection lines (7), and circulation head (8);[0076]step 5: maneuvering the WCT (10) and valves (12) to align the treatment with the reservoir rock (13);[0077]step 6: pumping the inhibitor solu...

example 3

Results

[0100]In the present invention, the process (P) and its interconnection with the system(S) allowed the gradual release of the scale inhibitor over a period of 2 to 3 years in oil wells with BSW less than or equal to 0.5%. Consequently, such a result allows for the postponement of scale removal operations, which subject the producing wells to production loss due to scale, difficulty in planning joint removal and inhibition operations, and the possible use of a rig and WSSV in operations outside the field management prediction, which impact these resources considered critical.

Claims

1. A system (S) for preventive inhibition of scaling in oil wells, comprising the following components and interconnections:a stimulation vessel interconnected to a completion rig;a drilling string interconnected at the top with the rig, and interconnected at the bottom with a production string; anda reservoir rock that externally surrounds the production string.

2. The system according to claim 1, wherein the interconnection of the vessel with the rig occurs by means of a transfer pipe directly connected to connection lines present in said rig, and said lines are consecutively connected to a circulation head also present in said rig.

3. The system according to claim 2, wherein the interconnection of the drilling string with the rig occurs by means of the circulation head.

4. The system according to claim 1, wherein the interconnection of the drilling string with the production string occurs by means of a wet Christmas tree, in which said production string comprises selective completion valves.

5. The system according to claim 1, wherein the vessel comprises a tank for storing a scale inhibitor, a tank for industrial water or a saline fluid, and a tank for preparing an inhibitor solution, in which the tank has interconnection with the tanks and.

6. A process (P) for preventive inhibition of scaling in oil wells, wherein it occurs in the system (S), as defined in claim 5, said process (P) comprising the following steps:transferring of the scale inhibitor, initially contained in the tank, to the tank; and transfer of industrial water or saline fluid, initially contained in the tank, to the tank;preparing the inhibitor solution in the tank;interconnecting vessel with the rig;interconnecting the components in the rig by means of the pipe, connection lines, and circulation head;maneuvering the wet Christmas tree and valves to align the treatment with the reservoir rock;pumping the inhibitor solution from the vessel to the rig through the tubing, followed by pumping said solution to the production string through the drilling string; andmaneuvering the valves to pump the inhibitor solution.

7. The process according to claim 6, further comprising the following steps:conditioning the reservoir rock after pumping the inhibitor solution from the vessel to the rig through the tubing, and pumping said solution to the production string through the drilling string, is completed;allowing action of the inhibitor solution in the reservoir; andpreparing the reservoir rock for opening and production.

8. The process according to claim 6, wherein the preparation of the inhibitor solution comprises the use of 5,000 liters of the scale inhibitor from the tank, and the use of 245,000 liters of water or the use of 245,000 liters of saline fluid, in which the saline fluid, when selected for use in the tank, is an aqueous solution of potassium chloride at a concentration of 2 to 3% m / V.

9. The process according to claim 8, wherein the scale inhibitor is a chemical formulation comprising a scale inhibitor selected from the group comprising phosphonates, phosphonate ethers, phosphate esters, polyacrylates, or glucosides, in which said scale inhibitor is present in said chemical formulation at a concentration between 10% and 50% m / V.

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