RU2191317C2 - Method of pipeline repairs - Google Patents

Abstract

FIELD: construction enginering; applicable in repairs of pipelines. SUBSTANCE: method includes installation of cylindrical coupling with branch pipes on damaged section of pipeline and formation of gap between them, sealing of coupling ends on pipeline and supply to circular gap of composite material in the form of polymer composition of cold hardening based on mixture of epoxide dian and aliphatic resins containing hardener in the form of mixture of Mannich's and Shiff's bases and dispersed filler. Ratios of components of polymer composition are offered. EFFECT: increased service life of pipelines. 3 dwg, 1 tbl

Description

 The invention relates to methods for repairing pipelines without stopping pumping the product, and in particular to a method for repairing a pipeline. Most effectively, the present invention can be used for pipelines transporting oil, oil products and / or gas. In addition, the invention can be used for pipelines for domestic and industrial use, transporting any other liquid medium, such as water.

 Pipelines for transporting liquid or gas under pressure are usually made of steel so that they can withstand the internal pressure created to transport fluids over long distances. Despite the complex of protective measures taken during the production and laying of the pipe forming the pipeline, corrosion damage to the pipeline can occur. Pipelines located in the ground are destroyed by soil corrosion, which is divided into chemical and electrochemical, electrical corrosion, external influences and pipe defects, welds and installation. See the book of authors A.G. Gumerov, H.A. Azmetov, R.S. Gumerov, M.G. Vekshtein "Emergency and repair repairs of main oil pipelines." M., Nedra, 1998, pp. 26-38. Accident statistics show that the above factors can cause corrosion ulcers and cracks in the pipe. In addition, the pipeline may be subject to mechanical damage, such as dents and corrugations left by the equipment used when laying the pipeline or when opening, inspecting and repairing the pipeline after it is laid. Such damage (dents and corrugations) weakens the pipe and can accelerate the corrosion process.

 The invention relates to methods for repairing axially extended structures characterized by the presence of an internal force directed radially outward, more precisely, methods for repairing and hardening a pipe in a pipeline through which oil or oil products or gas moves under pressure. The invention is aimed at hardening a corroded or otherwise damaged section of the pipeline without stopping the pumping of the product.

 The “smart” means of in-line diagnostics used on main pipelines make it possible to detect defects of various types in the linear part of pipelines. According to the results of strength analysis, those defects that pose a danger to the integrity of pipelines are subject to repair.

A known method of repairing a pipeline, which consists in cutting out defective pipe sections, and inserting new ones, although it is the most radical method of repair and is still widely used in various countries of the world, has, however, significant drawbacks, namely:
- requires a complete stop pumping of the product;
- the repaired section of the pipeline must be freed from oil with its removal through technological pipelines to a specially opened foundation pit or to another oil pipeline.

 Oil diversion works are very laborious, environmentally unsafe, entail the subsequent cleaning of the soil from oil pollution and the restoration of the surrounding area. The implementation of cutting repair technology is usually associated with significant costs.

 Cutting out defects and replacing sections of the pipeline is used in case of detection of an unacceptable narrowing of the passage diameter of the pipeline, the impossibility of ensuring the required degree of restoration of the pipeline during repair by other methods, and the economic inexpediency of using other repair methods due to the excessive length of the defective section.

 In addition to the "classical" clipping, abroad, a special technology is also used for cutting defective areas without stopping pumping. For example, T. D. WILLIAMSON technology incorporates an insert into a pressurized bypass line covering a section to be repaired. Inside the area covered by the bypass line, overlap nodes are installed on both sides. After the pipeline is shut off, oil moves along the bypass line, and the area between the overlap nodes is repaired. Upon completion of the repair, the pipeline overlap is removed and the bypass line is dismantled. The disadvantage of this cutting technology is the complexity, bulkiness and high cost of the equipment used, as well as a significant amount of welding work on the surface of the pipe under pressure.

 A known method and device for repairing a pipeline using a welded sleeve. A weld-in sleeve is welded to the pipe with sealing welded annular seams. In the process of welding stressed pipes in the welding zone, residual (welding) stresses arise, which, when combined with stresses from internal pressure, can lead to cracking. They can occur both in the process of heating and crystallization of the metal, and after cooling (technological strength). See the book of authors A.G. Gumerov, H.A. Azmetov, R. S. Gumerov, M. G. Vekshtein "Emergency and repair repairs of main oil pipelines". M., Nedra, 1998, pp. 81-95.

 In another known method (GB, A, 2210134) for repairing a pipeline, a method for repairing pipelines using cylindrical steel couplings with nozzles installed on defective sections of the pipeline is used; in this case, a non-welded sleeve (composite-sleeve technology) is installed around the damaged pipe (symmetrically with respect to the defect) with an annular gap of, for example, 18 mm in order to compensate for the ovality of the pipe and sleeve. After this, the ends of the coupling are sealed. The annular gap is filled with an epoxy resin composite material that adheres to the pipe and coupling, strengthens the damaged part of the pipeline and provides a sufficiently effective discharge of the defective pipe.

 A device for implementing this method includes a cylindrical sleeve, consisting of two coupling halves - lower and upper, which are connected together by welds when mounting the coupling on the pipeline. In this case, the coupling itself is not welded to the pipeline. The lateral edges of both coupling halves are cut for welding. In addition to a coupling with a welded joint of the coupling halves, a coupling with a flange connection of the coupling halves can be used, in this case the coupling of the coupling halves is carried out using studs that tighten the flanges.

 Couplings consist of two cylindrical coupling halves that are installed on the pipe being repaired, completely covering it. Then both coupling halves are butt welded with longitudinal seams with preliminary cutting of the edges. The inner diameter of the coupling exceeds the outer diameter of the pipeline by an amount sufficient to form an annular gap between them.

 In the lower coupling half is an inlet steel pipe, designed to connect a flexible hose to it, through which composite material is fed.

 An outlet steel pipe is located in the upper floor of the coupling. In addition, in the coupling itself there are control holes designed to release air and control the level of the composite material during pouring. As the coupling fills with composite material, bolts are screwed into the control holes.

 In addition, in both coupling halves there are threaded holes into which mounting bolts are screwed, designed to adjust the clearance between the coupling and the pipe and perform the function of supports when installing the coupling on the pipeline.

 The device operates as follows.

 Two halves of a steel coupling are mounted to each other, mounted on the pipe symmetrically with respect to the defect with an annular gap. The tolerance on the size of the annular gap allows repairing pipelines with geometry defects in the cross section and bending of the longitudinal axis. The ends of the coupling are filled with quick-setting sealant. The resulting volume between the pipe and the coupling through the inlet pipe in the lower floor of the coupling is filled with a composite material based on epoxy resin, hardening to the required strength within 24 hours.

 A significant drawback of this method is the fact that the degree of unloading of a pipe with a defect, the resource and durability of a pipeline having a defective area with damage depend on the physicomechanical and strength properties of the composite material filling the annular gap.

 The basis of the present invention is the creation of such a method of repairing a pipeline that would ensure the resource and durability of a pipeline having a defective area with damage for a life of at least the service life of a defect-free pipeline.

где R -(СН₂)_n- или -(C₂H₄NH₂C₂H₄)_n-, n = l-10,
представляющее собой продукт конденсации фенола, альдегида и алифатического амина, отличающаяся тем, что в составе смоляной части она дополнительно содержит эпоксидную алифатическую смолу в соотношении диановая смола: алифатическая смола от 20:30 до 95:5 и порошковый наполнитель, а в составе отвердителя - дополнительно основание Шиффа (Б), представляющее собой продукт взаимодействия алифатического ди- или полиамина с кетоном при соотношении А-Б от 5:95 до 95:5, при этом композиция содержит в массовых частях:
Смоляная часть - 100
Отвердитель - 10:60
Порошковый наполнитель - 20:800
Другие цели и преимущества настоящего изобретения станут понятны из следующего детального описания примера его выполнения и прилагаемых чертежей, на которых:
Фиг.1 изображает участок трубопровода с полумуфтами;
Фиг. 2 изображает устройство согласно изобретению, установленное на трубопроводе;
Фиг.3 изображает продольный разрез трубопровода с установленной муфтой.The problem is achieved in that in a method of repairing a pipeline, including installing a cylindrical sleeve with nozzles on a damaged section of the pipeline with the formation of an annular gap between them, sealing the ends of the sleeve on the pipeline and feeding into the annular gap between the sleeve and the pipe through its inlet pipe a composite material based epoxy resin before the appearance of the composite material in the outlet pipes, according to the invention, the composite material is a polymer composition of cold curing on os ove bisphenol epoxy resins containing as a hardener a Mannich base (A) of the general formula

where R - (CH ₂ ) _n - or - (C ₂ H ₄ NH ₂ C ₂ H ₄ ) _n -, n = l-10,
which is a condensation product of phenol, aldehyde and aliphatic amine, characterized in that in the resin part it additionally contains an epoxy aliphatic resin in the ratio diane resin: aliphatic resin from 20:30 to 95: 5 and a powder filler, and in the composition of the hardener additionally Schiff's base (B), which is the product of the interaction of an aliphatic di- or polyamine with a ketone at a ratio of AB from 5:95 to 95: 5, while the composition contains in mass parts:
Resin part - 100
Hardener - 10:60
Powder filler - 20: 800
Other objectives and advantages of the present invention will become apparent from the following detailed description of an example of its implementation and the accompanying drawings, in which:
Figure 1 depicts a section of the pipeline with coupling halves;
FIG. 2 shows a device according to the invention mounted on a pipeline;
Figure 3 depicts a longitudinal section of a pipeline with a mounted coupling.

 The first stage during the repair is to detect a defective section of the pipeline as a result of, for example, corrosion or dent. To detect a defect, for example, an “intelligent” means of in-line diagnostics can be used. The pipeline section in the defect zone is cleaned from insulation and processed using a shot blasting machine.

 A cylindrical sleeve 3 is installed symmetrically with respect to the defect 2 on the pipeline section 1 (Fig. 1-3) having a “dent” type 2, covering the pipeline 1 and consisting of the lower 4 and upper 5 coupling halves. The coupling halves 4 and 5 are joined together by welds when mounting the coupling 3 on the pipe 1, while the coupling 3 itself is not welded to the pipe 1. The inner diameter of the sleeve 3 exceeds the outer diameter of the pipe 1 by an amount sufficient to form an annular gap between them.

 The coupling halves are made from sheet material in the factory. As the material of the coupling, steel is used, similar to the steel of the pipe being repaired (with equivalent mechanical characteristics) and with a thickness not less than the nominal wall thickness of the pipe being repaired. The inner surface of the coupling halves is treated in the same way as the outer surface of the pipe to obtain the same adhesion between the composite material 6 and the metal of the coupling 3.

Coupling Installation:
Before pumping into the annular gap of the composite material 6 based on epoxy resin, the ends of the coupling are sealed with a sealant 7 (Fig. 3) based on polyester resin, which hardens within an hour. As sealant 7, any of the known materials suitable for this purpose can be used. The outer side of the sealed ends of the sleeve 3 is formed with a smooth contour, as shown in FIG. 3, in order to provide a denser wrapping with insulating tape for corrosion protection (not shown) of the repaired pipe.

 Steel inlet pipes 8 and 9 located at the edges are screwed into the lower coupling half 4. The output steel pipes 10 and 11 are screwed into the upper coupling half 5 located at the edges. The location of the input 8, 9 and output 10, 11 nozzles at the edges of the coupling halves allows you to effectively control the process of filling the peripheral space of the annular gap and completely eliminates the formation of air bubbles when filling the peripheral space of the annular gap with composite material. In addition, in the upper coupling half 5 there are three rows of control holes, into which control bolts 12 are screwed, designed to control the level of the composite material when filling the annular gap and the exit of air bubbles. When the composite material 6 exiting through the control holes is free of air bubbles, the holes are closed with control bolts 12.

 In both coupling halves 4 and 5, there are four threaded holes into which mounting bolts 13 are screwed, designed to adjust the annular gap between the coupling 3 and the pipeline 1 and perform the function of supports when installing the coupling 3 on the pipeline 1. After performing the technological operation of sealing the ends of the coupling 3 (Fig.3) the mounting bolts 12 are turned out flush with the edges of the coupling 3.

 On the pipe 8 put on one of the ends of the reinforced hose 14 with a length of at least 0.5 m, fix it on the pipe 8 with a clamp 15, then install a clip 16 on the hose, while the other end of the hose 14 is connected to the discharge pump (in figure 2 not shown). The discharge pump can be connected both to the inlet pipe 8 and to the inlet pipe 9, which is equivalent.

 Reinforced hoses 17, 18, 19 are put on the pipes 9, 10, 11, at least 0.5 m long, fixed with clamps 20, 21, 22 and clamps 23, 24 and 25 are put on them, respectively.

 The device operates as follows.

 The injection pump is turned on and composite material 6 is pumped through the reinforced hose 14 into the annular gap until the composite material 6 appears in the reinforced hose 17 of the inlet pipe 9.

Preparation of polymer composition
The polymer composition is prepared immediately before use.

 The composition of the polymer composition is given in the table.

 Example 1. In a reactor equipped with a stirrer, load 100 wt. parts of the resin part and 35 wt. parts of hardener, mix thoroughly for 2 minutes, then add 410 wt. parts of the filler.

 Examples 2-16 are carried out in a similar manner with the ratio of components shown in the table.

 The injection of the composite material 6 is continued until the entire reinforced hose 17 is filled with the composite material. After that, the pump is stopped and, with the help of clamp 23, the reinforced hose 17 of the inlet pipe 9 is closed. After that, the pump is turned on and the annular gap 6 is filled with composite material until the reinforced hoses 18 and 19 of the extreme outlet pipes 10 and 11 are filled with composite material 6. Stop the pump and use the clamps 24 and 25 to block the outlet pipes 10 and 11 and the inlet pipe 8 using the clamp 16. Disconnect the pump from the hose 14.

 The pressure at the pump outlet when the composite material 6 is fed into the annular gap is maintained at a level of 7-10 atm.

 Composite material 6 in the annular gap hardens to the required strength within 24 hours. After curing the composite composition in the annular gap, all protruding parts (inlet 8, 9 and outlet 10, 11 nozzles, control 12 and installation bolts 13) on the cylindrical surface of the sleeve 3 are removed and a smooth outer surface is applied to apply the insulation tape as a corrosion protection to the repaired area the pipeline.

Claims (1)

A method of repairing a pipeline, including installing a cylindrical coupling (3) with nozzles (8, 9, 10, 11) on a damaged section of the pipeline (1) with the formation of an annular gap between them, sealing the ends of the coupling (3) on the pipeline (1) and feeding an annular gap between the sleeve (3) and the pipe (1) through its inlet pipe of the composite material based on epoxy resin until the composite material appears in the output pipes, where the composite material is a cold cured polymer composition based on epoxy dianes resins as hardener Mannich base (A) of the general formula

where R: - (CH ₂ ) _n - or - (C ₂ H ₄ NH ₂ C ₂ H ₄ ) _n -, n = 1-10,
which is a condensation product of phenol, aldehyde and an aliphatic amine, characterized in that the resin part additionally contains an epoxy aliphatic resin in the ratio diane resin: aliphatic resin from 20:30 to 95: 5, a powder filler, and an additional base in the hardener Schiff (B), which is the product of the interaction of an aliphatic di- or polyamine with a ketone at a ratio of A: B from 5:95 to 95: 5, while the composition contains, by weight:
Resin part - 100
Hardener - 10-60
Powder filler - 20-800o

Images