Method for cleaning wells and pipelines using exothermic cleaning agent

Abstract

FIELD: major and routine repairs of wells and pipelines.SUBSTANCE: heating area corresponding to the edge of the plug is determined, the type, shape and size of the solid chemically active substance are selected, the time for the chemically active substance to reach the heating area is calculated, the residual pressure is released, after which an exothermic cleaning agent is directed into the open end of the well or pipeline, including a chemically active substance, an activating agent of greater density than the intra-pipe fluid, and an inert agent, the holding time is observed and the work cycle is repeated until an increase in the intra-pipe pressure occurs, caused by a breakthrough of the plug. An exothermic cleaning agent is supplied to a well or pipeline in the form of an exothermic projectile in which a chemically active substance is coated with a layer of an inert agent, and an activating agent is enclosed in a soluble shell, or in the form of separate elements including a chemically active substance coated with a layer of an inert agent, and an activating agent enclosed in a soluble shell. The projectile and individual elements are fed through a tubular guide device, which is pre-installed on the free end of the well or pipeline.EFFECT: efficiency of the method of cleaning wells and pipelines using an exothermic cleaning agent is increased while reducing time losses and material consumption.7 cl, 13 dwg

Description

[0001] The claimed invention relates to the transport of gas and oil and gas condensate flows, in particular to the field of major and current repairs of wells and pipelines and can be used for the decomposition of gas hydrate deposits.

[0002] There is a problem associated with the formation of gas hydrate deposits on the walls of vertical wells and horizontal non-metallic pipelines. To remove these deposits, differential pressure, hydraulic, mechanical, thermal, and chemical treatments are used. Of particular interest to companies operating such pipelines are methods that can be implemented without costly tripping operations when cleaning vertical pipelines. When cleaning horizontal non-metallic pipelines, it is essential to ensure deposit removal without interrupting the flow of the pumped fluid, which would lead to significant losses due to lengthy downtime for repairs. For polymer-reinforced pipelines, it is crucial to prevent overheating of the outer wall, as this can lead to destruction.Existing solutions are accompanied by an inefficient loss of both time for loading the pipeline being cleaned and the loss of chemically active materials, and do not fully ensure an increase in the intensity of heat generation in the local zone corresponding to the area of ​​gas hydrate deposits, regardless of their location at the very beginning and during cleaning.

[0003] A device for breaking up asphaltene-resin and paraffin hydrate deposits in a well is known from the prior art (RU Patent No. 2105867, published February 27, 1998). The device comprises an aluminum shell filled with a chemically active mass based on at least one alkali metal. The active mass is coated with bitumen. A layer of a mixture of paraffin and transformer oil is applied to the outside of the shell, covered on the outside with aluminum powder. The shell is typically made of aluminum foil. The active mass may consist of two cylindrical halves, forming a closed through or sectional cavity inside, filled with a filler (aluminum powder or a mixture of aluminum powder and a weighting agent, or a surfactant and / or an emulsifier and / or a catalyst). The filler is used in the form of powder, granules, or tablets. The invention described has significant limitations in application, since the use of an alkali metal is dangerous due to the high risk of explosion and fire.Furthermore, the chemical reaction can create solid residues of unreacted materials, clogging the pipeline being cleaned. Another drawback of the invention is that feeding the described device into the pipeline requires significant time when using standard sealing equipment, which has design limitations on the volume of material that can be loaded simultaneously.

[0004] A device and method for removing asphaltene, resinous, and paraffin hydrate deposits are known (RU Patent No. 2123101, published December 10, 1998). To remove deposits, a device is used comprising a housing filled with a chemically active substance capable of interacting with water. The housing is a cylindrical shell made of aluminum or its alloy. The chemically active substance, metallic sodium, fills the housing in such a way that there is free space inside the shell, which is used to connect the devices together. The weight of the aluminum housing relative to the weight of metallic sodium is no more than 1 / 3. According to the method, the device is inserted into a lubricator and lowered under the action of its weight. Deposits are removed through thermochemical treatment when the water content in the oil is at least 60 wt.%. Pressure is periodically released through the well valve. The device has the following disadvantages.Firstly, it contains explosive and poorly soluble substances, which is unacceptable during oil and gas well operations, as there is no guarantee of a stable chemical reaction and can lead to explosions, fires, and clogging. Secondly, feeding these devices through a standard lubricator results in significant time losses due to its small capacity and the need to constantly open and close valves, making it impossible to load a large batch of devices in a single run.

[0005] A known method for breaking up asphaltene-resin and paraffin-hydrate deposits in a well and a thermochemical element (patent no. 2238394, publication date October 20, 2004) is used. The thermochemical element comprises a chemically active mass prepared on the basis of at least one alkali metal, enclosed in an insulating shell. The weighting agent is uniformly distributed throughout the volume of the chemically active mass and represents particles of a material with a specific gravity greater than unity and a size of no more than 0.5 mm. The chemically active mass can be made of a sodium-lithium alloy. The amount of lithium is no more than 6% of the chemically active mass. The insulating shell is designed to form an open, limited surface in it, before introducing the element into the well, for the direct interaction of the chemically active mass with the wellbore fluid. Thermochemical elements are introduced from the wellhead through a lubricator into the well.When a chemically active mass interacts with water contained in the wellbore fluid, a thermochemical reaction occurs, releasing heat. The reaction site moves toward the wellbore under the force of gravity and the destruction of asphaltene-resinous and paraffin-hydrate deposits (hereinafter referred to as ASS). The ASS is destroyed by gradually increasing the nominal bore size of the ASS. This is accomplished by sequentially introducing thermochemical elements of increasing external size. In the final stage, extended thermochemical elements with a longitudinal, through-axial channel are introduced. This method is primarily limited to cleaning shut-in wells, as the upward flow of fluid during submersible pump operation will inevitably carry the thermochemical element and its reaction products away from the cleaning zone toward the wellhead, reducing efficiency and increasing material consumption.However, using a standard downhole lubricator does not allow for the simultaneous loading of a large batch of thermochemical elements, which increases cleaning time. Furthermore, the chemical reaction involves explosive substances prone to spontaneous combustion, posing a hazard to personnel.

[0006] The closest approach to the claimed invention is a method for dissolving hydrate-paraffin and ice plugs in a vertical pipeline (RU Patent No. 2821674, published June 26, 2024). This method involves determining the required heating zone corresponding to the upper region of the plug. Next, the type, shape, and size of the solid chemically active substance are selected, and the time it takes for it to sink under its own weight in the pipeline to the specified heating zone is calculated. This substance is then introduced into a sealed casing made of a water-soluble polymer film with a known dissolution time. The residual pressure is then released, and the in-line fluid is replaced with another, more inert and less dense liquid relative to the solid chemically active substance. This polymer-cased substance is then lowered into the open end of the pipeline, where it falls under its own weight to the level of the plug.After this, the activator agent is prepared for injection into the pipeline, ensuring that its density is greater than that of the inert liquid and less than that of the solid chemically active substance. The activator agent is then injected into the pipeline and allowed to settle to the plug level as a separate layer. The required holding time is maintained until the active phase of the chemical reaction within the activator agent layer is complete. The process, which includes lowering the polymer-coated solid chemically active substance into the pipeline, injecting a portion of the activator agent, and then holding it, is repeated until the internal pipeline pressure increases due to the plug breaking through. The molten remains of the plug are forced up the pipeline by the reservoir pressure, along with the reaction products.A disadvantage of the invention is that increasing the intensity of heat generation in a localized zone corresponding to the gas hydrate deposits is only feasible at the initial stage of the work under the following conditions: if the gas hydrate deposits are located close enough to the free end of the vertical pipeline, corresponding to the wellhead, and the volume of in-line fluid being replaced is small, since the use of pumps to pump this fluid significantly reduces the positive effect. The method for delivering the activator agent described in the invention cannot ensure the required ratio of the main components for a complete chemical reaction within a short period of time due to inevitable losses associated with the insufficient uniformity of the inert agent's spread as it enters the heating zone.Moreover, the introduction of each batch of chemically active substance into a protective soluble shell immediately before lowering it into the pipeline and its subsequent delivery in the described manner requires a significant investment of time.

[0007] The problem that the claimed invention is aimed at solving is to develop a method for cleaning wells and pipelines from gas hydrate deposits, within the framework of which an exothermic cleaning agent is used, launched through a guide device.

[0008] The technical result of the invention consists in increasing the efficiency of the method for cleaning wells and pipelines using an exothermic cleaning agent, namely in reducing the loss of time and material consumption, taking into account the increase in the intensity of heating of deposits in a local zone for cleaning both wells and pipelines from gas hydrate deposits.

[0009] The technical result is achieved by using a method for cleaning wells and pipelines, which includes the stages of determining the heating area corresponding to the edge of the plug, then selecting the type, shape and size of the solid chemically active substance, calculating the time for the chemically active substance to reach the heating area, then releasing the residual pressure, after which an exothermic cleaning agent is directed into the open end of the well or pipeline, including a chemically active substance, an activator agent7 of greater density than the intra-pipe fluid, an inert agent, observing the holding time and repeating the work cycle until an increase in the intra-pipe pressure occurs, caused by a breakthrough of the plug.The exothermic cleaning agent is fed into a well or pipeline in the form of an exothermic projectile, in which the chemically active substance is covered with a layer of an inert agent, and the activating agent is enclosed in a soluble shell, or in the form of separate elements, including a chemically active substance covered with a layer of an inert agent and an activating agent enclosed in a soluble shell, wherein the feed of said projectile and separate elements into the well or pipeline is carried out through a tubular guide device, which is preliminarily installed on the free end of the well or pipeline.

[0010] The method may be implemented by using a guide device consisting of two pipe sections, with an inlet shut-off element or plug and an outlet shut-off element secured to the ends. After the exothermic cleaning agent has been supplied, the free end of the guide device is raised to a vertical position and secured with a locking mechanism. The outlet shut-off element is then opened, allowing the exothermic cleaning agent to be lowered into the well or pipeline. The pressure readings are recorded with a pressure gauge, and when they cease to change, the pressure is vented to zero by opening the drain shut-off element on the guide device, recording the readings with a gas flow meter to calculate the volume of hydrate subjected to decomposition. The outlet shut-off element is then closed, and the above steps for supplying the exothermic cleaning agent are repeated until the pressure ceases to drop to zero.

[0011] When implementing the method using a guide device containing an inlet shut-off element, the inlet shut-off element is opened before the exothermic cleaning agent is fed into the guide device, and then closed.

[0012] When implementing this method, a guide device can also be used, the pipe sections of which are connected by a flexible element or a bracket and quick-release couplings. Additionally, an exothermic projectile with a longitudinal through-axial channel can be used.

[0013] When implementing the method, a guide device in the form of a shell containing a return mechanism and a position sensor, one of the ends of which is turned inside out, made of a heat-conducting material, can be used, while the guide device is fed into the well or pipeline together with an exothermic projectile installed in it, containing a longitudinal through axial channel, and when repeating the work cycle, the exothermic projectile is fed in the direction of the guide device already placed in the well or pipeline.

[0014] When using an exothermic projectile with a longitudinal through axial channel in the process of implementing the method, one of its channels can be sealed with a soluble shell.

[0015] The essence of the claimed invention is explained by figures, which depict the following:

[0016] Fig. 1 - schematic view of the guide device in the form of long and short sections of pipes connected to each other by a flexible element,

[0017] Fig. 2 is a schematic view of a guide device in the form of long and short sections of pipes connected to each other by a bracket,

[0018] in Fig. 3 - the position for activating the chemical reaction of the guide device in the form of long and short sections of pipes connected to each other by a flexible element,

[0019] in Fig. 4 - position for loading with exothermic cleaning means the guide device in the form of long and short sections of pipes connected to each other by a flexible element,

[0020] in Fig. 5 - the position for activating the chemical reaction of the guide device in the form of long and short sections of pipes connected to each other by a bracket,

[0021] in Fig. 6 - position for loading with exothermic cleaning means the guide device in the form of long and short sections of pipes connected to each other by a bracket,

[0022] Fig. 7 - schematic view of the guide device in the form of a shell,

[0023] Fig. 8 - schematic view of a guide device in the form of a shell moving along a pipeline,

[0024] Fig. 9 is a schematic representation of an activator agent in an embodiment of an exothermic cleaning agent, in which the chemically active substance and the activator agent are separated from each other in the form of separate elements,

[0025] Fig. 10 is a schematic representation of a chemically active substance in an embodiment of an exothermic cleaning agent, in which the chemically active substance and the activating agent are separated from each other in the form of separate elements,

[0026] in Fig. 11 - a variant of the exothermic projectile, in which the chemically active substance and the activating agent are made in the form of a single element,

[0027] in Fig. 12 - a variant of the exothermic projectile, made in the form of a single element with a layered horizontal arrangement of the main components, having a longitudinal axial channel,

[0028] in Fig. 13 - a variant of the exothermic projectile, made in the form of a single element with a layered vertical arrangement of the main components, having a longitudinal axial channel.

[0029] The numbers represent the following: 1 - inlet shut-off element, 2 - long pipe section, 3 - short pipe section, 4 - outlet shut-off element, 5 - flexible element, 6 - pressure gauge, 7 - pressure reducing valve, 8 - gas flow meter, 9 - flexible hose, 10 - drain shut-off element, 11 - receiving tank, 12 and 13 - quick-release couplings, 14 - bracket, 15 - exothermic cleaning agent, 16 - pipeline, 17 - shell, 18 - flexible centering elements, 19 - position sensors, 20 - guide device, 21 - activator agent, 22 - activator agent shell, 23 - chemically active substance, 24 - inert agent.

[0030] The claimed method for cleaning wells and pipelines is implemented using a complex that includes an exothermic cleaning agent 15 and a guide device (according to Figs. 1-8) of a tubular shape that ensures the supply of said exothermic cleaning agent 15 into the well or pipeline.

[0031] Exothermic cleaning agent 15 in the form of an exothermic projectile (Fig. 11-13) or in the form of individual elements (Fig. 9-10) consists of a chemically active substance 23 covered with a layer of inert agent 24, on top of which there is an activator agent 21 covered with a soluble shell 22. As a chemically active substance 23, Na4Si4, or Ca, or LiAI(OH)4, or Ca with additives of F, or Ca with additives of Al and / or Mg, or a compound NH4NO3: S, or a compound NH4NO3: NaNO2, or a compound NaNO2: NH4CL, or a compound NaNO2: CO(NH2)2: H2N-SO2OH, or a compound Na2SO4: NH4CL, or a compound CaC2, as well as their combinations in any possible combinations and proportions are used. As a soluble shell 22, C6H12O6 or (CH2CHOH)n, or C12H22O11, or C12H24O11, or C5H12O5, or C6H14O6, as well as their combinations in any possible combinations and proportions are used.Inert agent 24 may be C8H18 or CnH2n+2, or (CnH2n)m, or any combinations thereof in any possible proportions. CaCl2 or CH3COOH or N2O5, or any combinations thereof in any possible proportions, may be used as activator agent 21. The ratio of the exothermic projectile components is not the subject of the claimed technical solution and does not affect the achievement of the intended technical result. In certain cases, the chemically active substance is not a solid (e.g., metallic calcium), but is a powder coated with a soluble shell similar to that enclosing the activator agent. The thickness of the inert agent 19 layer and the soluble shell 17 of the activator agent 16 are determined in advance by calculation or empirically, taking into account that the greater the thickness of the soluble shell 17, the longer the time required for the chemical reaction to begin.For example, 1 mm of an inert agent layer delays the onset of a reaction by approximately 5 minutes, while 1 mm of a soluble shell layer delays the onset of a chemical reaction by approximately 1.5 minutes.

[0032] The chemically active substance 23, activator 21, and inert agent 24 can be combined into a single element, an exothermic projectile, or the chemically active substance 23 and activator 21 can be separated into individual elements. The entire exothermic projectile, as well as its individual elements, are predominantly cylindrical. Designing the exothermic projectile as a single unit ensures the best cleaning interval is achieved in the presence of fluid flow through the well or pipeline. In this case, the ratio of the projectile's components is not disrupted, and the projectile performs its intended function. Designing the exothermic cleaning agent as individual elements is preferable when there is no fluid flow or only minor fluid flow.

[0033] In some versions, a thickener of known composition (e.g., RH3OL 3K, Carbomer, Aerosil) is added to the activator agent 21. The thickener prevents uncontrolled spreading, ensuring the gel-form activator agent can reliably reach the cleaning interval even if there is fluid movement in the well or pipeline and / or if the cleaning zone is subject to high temperatures. Furthermore, the thickener is necessary to extend shelf life if the storage temperature in the warehouse or during transportation exceeds the permissible limit. A longitudinal axial channel, obtained, for example, by drilling, extrusion, molding, or spiral twisting, can pass through the exothermic projectile, and one end of this channel can be sealed with a soluble shell.This design allows the tool to move along a pipeline or well in a specific direction with minimal hydraulic resistance in the presence of fluid flow. Specifically, an exothermic tool with a longitudinal axial channel, one end of which is plugged, can be used primarily in horizontal pipelines where fluid flows. Alternatively, a similar tool with an unplugged axial channel can only be used in vertical sections of pipelines or wells where fluid does not flow freely.

[0034] Guide device 20 can be made from two pipe sections connected to each other (e.g., a long section 2 and a short section 3). One of the pipe sections is intended for placement directly on the surface of the well or pipeline, while the other is capable of changing its position from vertical to an inclined (horizontal) position relative to the well or pipeline. In this case, the preferred embodiment is one in which the pipe section intended for placement on the surface of the well or pipeline is shorter than the second section, sinceWhen using a guide device in a vertical well or pipeline, there is a relationship according to which the longer the surface pipe section, the greater the distance the exothermic cleaning agent will travel downward when it is delivered and the greater the risk of its failure upon impact with the outlet shutoff element or valve (or tap) of the well or pipeline, due to the fragility of the activating agent coating. Alternatively, the pipe sections can be of equal length and contain a soft coating (such as butyl rubber) inside, which cushions the descent of the exothermic cleaning agent without impact by reducing its fall velocity. The pipe sections are connected in series, providing an adjustable angle relative to each other.For example, sections of pipes 2 and 3 can be connected by a flexible element 5 so that their internal diameter corresponds to the internal diameter of the well or pipeline, and an inlet shut-off element 1 or plug and an outlet shut-off element 4 are fixed to the ends of the guide device, the latter of which is hermetically connected to the pipeline or well being cleaned. A locking mechanism is fixed to the surface of the pipe section located on the surface of the well or pipeline (short section 3) of the guide device 20, and a pressure gauge 6, a pressure-reducing valve 7, a drain shut-off element 10 and a gas flow meter 8 are also fixed through a branch pipe, the free end of which is connected via a flexible hose 9 to a receiving container 11 for draining the reaction products.The design options for the locking mechanism may vary, but they are all aimed at ensuring the fixation of the guide device 20 in the assembled vertical position (for example, placing the flexible element 5 inside the support sleeve when giving it a vertical position manually or using pulley blocks and a traction drive, or using magnets, clamps or clamps, or spring-loaded brackets).

[0035] Another possible embodiment of the guide device is one in which the pipe sections of the guide device 20 are connected to each other using a bracket 14 and a locking mechanism in the form of quick-release connections 12-13 of a known design (or another known mechanism, such as a flange), and the free end of the pipe section installed on the well or pipeline is provided with a plug. The locking mechanism may be, for example, a nut placed over the pipe section and screwed to the mating threaded portion of the pipe section of this guide device according to the principle of a quick-release connection, in which tightness is achieved by using a conical triangular thread, or a locking mechanism in the form of a bolted connection of two flanges.Similar to the embodiment of the guide device with flexible element 5, the design provides for the presence of a branch pipe on which a pressure gauge, a pressure-reducing valve, a drain shut-off element and a gas flow meter are attached, the free end of which is connected via a flexible hose to a receiving container for draining the reaction products.

[0036] The pipe section of the guide device 20, located on the surface of the well or pipeline, can be connected to the pipeline or well to be cleaned directly without the outlet shut-off element 4. This option is only possible if the pipeline or well already has a tap or valve located near the open end of the pipeline or well, and there is no need to quickly perform the opening and closing operation.

[0037] The guide device may be a shell 17 (a more compact design), one end of which is turned inside out, forming a hemisphere in longitudinal section. In this case, the guide device is made of a heat-conducting material, to the outer surface of which, along the axis of the guide device, flexible centering elements 18 (e.g., spacers) are attached. This design of the guide device allows for heating through the shell, which conducts heat well. If the pipeline or well being cleaned does not have a receiving chamber, the guide device is equipped with a return mechanism (not shown in the figure) and a position sensor 19. The return mechanism is designed to return the guide device and is represented by a cable that is attached to the free end of the shell, and a traction mechanism (winch).When using a return mechanism, an additional sealing device is installed on the inlet shut-off element of the starting chamber to allow free movement of the cable without loss of tightness.

[0038] A method for cleaning wells and pipelines using an exothermic cleaning agent in both its projectile and individual component forms is implemented as follows. Known methods are used to determine the required heating area of ​​the well or pipeline, corresponding to the edge of the gas hydrate plug (its upper or front region, depending on the well or pipeline orientation—vertical or horizontal), as well as the gas content of the deposit. Next, depending on the initial requirements for the chemical reaction components and the properties of the in-line fluid, the type, shape, and size of the exothermic cleaning agent are selected. This consists of a chemically active substance coated with a layer of an inert agent and an activating agent enclosed in a sealed shell. The time required for the exothermic cleaning agent to reach the specified heating area in the well or pipeline is calculated.Residual pressure is relieved and a guide device is installed at the free end of the pipeline or well. Before relieving excess pressure, a carbon filter can be installed at the free end of the guide device. It is preferable to install the carbon filter after the chemical reaction has completed and the pressure needs to be relieved, either downstream of the inlet shutoff valve or in place of the plug. If a carbon filter is installed in place of the plug, another shutoff valve must be installed upstream.

[0039] Inject the exothermic cleaning agent into the well or pipeline through the installed guide device. Observe the holding time and repeat the process until the internal pipeline pressure increases due to the plug breaking through.

[0040] The system is suitable for use in both horizontal and vertical wells and pipelines. For vertical wells and pipelines, the preferred design is a two-section guide device, while for horizontal wells and pipelines, a guide device with a shell is preferred, as it prevents the chemical action of the exothermic cleaning agent from dissipating and heating up in the fluid flow.

[0041] When implementing the method for cleaning wells and pipelines, preferably of the vertical type, a guide device with closed shut-off elements (1), (4), (10) (Fig. 1) is installed on the free end of the pipeline or well. One of the ends of this device is lowered downwards (Fig. 4) so ​​as to conveniently carry out the loading of the exothermic cleaning agent. The inlet shut-off element (1) is opened. At a negative outside air temperature, the guide device is pre-washed with an antifreeze composition. Then, the exothermic cleaning agent in the design according to Fig. 3 is loaded, observing the planned ratio of the components. The inlet shut-off element (1) is closed and the free end of the guide device is raised manually or using a return mechanism (not shown in the figure) to a vertical position (Fig. 3) and secured using a locking mechanism (not shown in the figures).The outlet shut-off element (4) is then opened, causing the exothermic cleaning agent to drain into the pipeline. Under its own weight, the exothermic cleaning agent sinks into the in-line fluid to the deposit location. This releases a large amount of gas and heat, melting the deposits. The holding time is observed and the readings on the pressure gauge (6) are recorded. When the readings stop changing, the pressure is released to zero by opening the drain shut-off element (10) on the guide device. The pressure, gas flow rate, and gas flow rate are recorded, and these values ​​are subsequently used to calculate the volume of hydrate decomposed using known methods.If the expected pressure is absent after the work has been completed, the pipeline is filled with the calculated amount of activator agent in liquid form, the excess of which, as well as the excess of reaction products, are drained with the drain shut-off element (10) open into the receiving tank (11) via a flexible hose (9) for subsequent disposal. After which the outlet shut-off element (4) is closed and the guide device is again lowered to the loading position (Fig. 4), having first released it using the locking mechanism (not shown in the figure). The inlet shut-off element (10) is opened and the exothermic cleaning agent is loaded. If necessary, the ratio of the main components of the chemical reaction is changed by changing the amount of activator agent and chemically active substance supplied to the pipeline. Then the procedure of feeding the exothermic cleaning agent into the well or pipeline and taking measurements is repeated. In case of a positive progress of the cleaning process, the ratio of the components is maintained.Otherwise, repeat the injection of the liquid activator and adjust the component ratios until the cleaning process proceeds as planned. The cleaning process is complete when the pressure on the pressure gauge stops dropping to zero after being released by opening the drain shut-off valve (10) and then opening the outlet shut-off valve (4).

[0042] If the size of the gas hydrate plug exceeds the calculated values ​​of the ratios of the main components of the exothermic reaction, at which the chemical reaction is possible, shells with a soluble shell filled with ice or water are additionally lowered into the well or pipeline until the chemical reaction is ensured again.

[0043] If there is no pressure in the well or pipeline, or if it is insignificant, after the loading of the exothermic cleaning agent has been completed and the inlet shut-off element (1) has been closed, it is advisable to immediately open the outlet shut-off element (4) immediately before raising the guide device to the position for activating the chemical reaction (Fig. 4) in order to avoid premature damage to the fragile soluble shell of the cleaning agent against the closed outlet shut-off element (4).

[0044] When implementing the method for cleaning wells and pipelines, preferably of the horizontal type, a guide device in the form of a shell (17) is installed on the free end of a pipeline or well and an exothermic projectile in the design according to Fig. 7, having a longitudinal axial channel, is placed in it, fed into the operating pipeline through a standard launch chamber (not shown in the Fig.). The guide device is moved along the well or pipeline by the pumped flow and is centered by flexible elements (2), Fig. 7. The time required for the guide device to reach the cleaning area and the holding time until the active phase of the chemical reaction is completed are observed. Upon reaching the cleaning area, a large amount of gas and heat is released, which heats up the end of the shell (17) in the shape of a half, and melts the deposits, which are pushed out along the well or pipeline along with the reaction products.In parallel, the temperature of the outer surface of the well or pipeline in the intended cleaning area is monitored using known methods, allowing the current position of the guide device with the projectile to be determined. In some designs, the position of the guide device is determined using a position sensor (3) or by measuring the length of the return mechanism cable, the distance the guide device has moved during cleaning. The calculated and actual cleaning process parameters are refined. Then, after the holding time, an additional exothermic projectile (Fig. 8) can be fed through the launch chamber, which is carried by the flow toward the guide device already positioned in the pipeline. Upon reaching the guide device, the projectile is positioned coaxially within it, providing subsequent heating of the deposit formation area.After this, the holding time is observed and the process is repeated until the intended repair zone, controlled from the outside of the pipeline, is overcome.

Claims

1. A method for cleaning wells and pipelines, which includes the steps of determining the heating area corresponding to the edge of the plug, then selecting the type, shape and size of the solid chemically active substance, calculating the time for the solid chemically active substance to reach the heating area, then releasing the residual pressure, after which an exothermic cleaning agent is directed into the open end of the well or pipeline, including a solid chemically active substance, an activator agent of greater density than the in-line fluid, and an inert agent, observing the holding time and repeating the work cycle until an increase in the in-line pressure occurs, caused by a breakthrough of the plug, characterized in that the exothermic cleaning agent is fed into the well or pipeline in the form of an exothermic projectile, in which the solid chemically active substance is covered with a layer of an inert agent, and the activator agent is enclosed in a soluble shell, or in the form of separate elements,including a solid chemically active substance covered with a layer of an inert agent and an activating agent enclosed in a soluble shell, wherein the feed of said projectile or individual elements into a well or pipeline is carried out through a tubular guide device, which is preliminarily installed on the free end of the well or pipeline.

2. The method according to claim 1, characterized in that a guide device is used, consisting of two sections of pipes, on the ends of which an inlet shut-off element or plug and an outlet shut-off element are fixed, wherein after the exothermic cleaning agent is supplied, the free end of the guide device is raised to a vertical position, securing it with a locking mechanism, after which the outlet shut-off element is opened, ensuring the descent of the exothermic cleaning agent into the well or pipeline, the readings are recorded with a pressure gauge and when they stop changing, the pressure is released to zero by opening the drain shut-off element on the guide device, recording the readings with a gas flow meter to calculate the volume of hydrate subjected to decomposition, after which the outlet shut-off element is closed and the above actions for supplying the exothermic cleaning agent are repeated until the pressure stops dropping to zero.

3. The method according to paragraph 2, characterized in that the inlet shut-off element is opened before the exothermic cleaning agent is fed into the guide device, after which it is closed.

4. The method according to any of paragraphs 2, 3, characterized in that a guide device is used, the pipe sections of which are connected to each other by a flexible element or by means of a bracket and quick-release connections.

5. The method according to any of paragraphs 1-4, characterized in that an exothermic projectile is used that has a longitudinal through axial channel.

6. The method according to paragraph 1, characterized in that a guide device is used in the form of a shell containing a return mechanism and a position sensor, one of the ends of which is turned inside out, made of a heat-conducting material, wherein the guide device is fed into the well or pipeline together with an exothermic projectile installed in it, containing a longitudinal through axial channel, and when the work cycle is repeated, the exothermic projectile is fed in the direction of the guide device already placed in the well or pipeline.

7. The method according to any of paragraphs 5, 6, characterized in that one of the ends of the longitudinal through axial channel of the exothermic projectile is sealed with a soluble shell.

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