EA039461B1 - Method for monitoring corrosion processes - Google Patents

Abstract

The invention relates to means for monitoring and diagnosing corrosion processes inside technical equipment and pipelines. A method for monitoring corrosion processes includes installing a marker, sampling a fluid, and monitoring indicators. A marker is installed on the inside surface of an item to be inspected. Said marker is selected such that it can be applied to a metal surface, is resistant to the working fluid, does not contain any of the substances contained in the working fluid, is biologically and chemically inactive with respect to the working fluid and the surface to which it is applied, and is resistant to the effect of pressure and temperature. The marker is then applied to predetermined regions of the item to be inspected. Said item is put into operation and filled with a working fluid. Once a corrosion process begins, the marker applied to the regions subject to corrosion, together with particles of metal or of an anticorrosive coating on said regions subject to corrosion, peels off the item. The marker then passes into a fluid sampling zone for monitoring of the concentration of markers which indicate the presence of corrosion, the time period within which corrosion took place, and the intensity of the corrosion process. Differently identifiable markers are applied to different designated regions of the item. The corrosion rate is determined according to the concentration of the amount of the markers during the inspection period. A marker is selected from fluorescent substances, or radical-type indicators, or substances with high thermal neutron absorption, or radioactive isotopes, or coloured substances. The marker is applied to a maximum area of potential corrosion.

Description

State of the art

Currently, 350,000 km of field pipelines are in operation in Russia. Every year, about 50-70 thousand failures occur on oilfield pipelines. 90% of failures are the result of corrosion damage.

Of the total number of accidents, 50-55% are accounted for by oil gathering systems and 30-35% - by formation pressure maintenance communications. 42% of pipes do not withstand five years of operation, and 17% - even two years. The annual replacement of oilfield networks consumes 7-8 thousand km of pipes or 400-500 thousand tons of steel. Depressurization of pipelines and process equipment causes enormous damage to the flora and fauna of the region where companies operate.

Timely identification of the presence and location of corrosion in technological devices, pipelines and engineering networks in the process of continuous operation can prevent many forced downtime and emergency situations, determine the most typical places for the occurrence of defects, which should be focused on during inspections.

At present, the main tool of the system of diagnostic inspection of pipelines is in-line diagnostics. To date, various methods for diagnosing pipelines based on various physical laws are used.

Diagnostics of pipelines with the help of video filming.

The use of the most modern methods for analyzing the state of pipelines is always accompanied at the final stage by a visual inspection for the fact of detection of defects and omissions during automatic inspection. The quality of pipelines has recently been checked using video diagnostics from inside the pipe; in-pipe diagnostics of pipelines is carried out by special robots, which gradually move along the pipe channel, form a continuous image, thereby revealing defects that require localization. This method is able to detect only gross violations of the continuity of pipelines, detect leaks in sections located in the ground or closed tunnels, as well as places of clogging and sedimentation of silt.

Pressurization of pipes.

As the oldest and most reliable method, which has high accuracy and reliability in combination with a low cost of implementation, the high-pressure pipe crimping method is used. After the installation of the pipeline, a gas mixture, mainly inert gases or water vapor, is supplied to it under high pressure (exceeding the operating pressure by about several times). Further, joints, welds and places of attachment of pipelines to boiler equipment are observed. Due to the difference in pressure inside and outside the pipe, the leak is immediately visible due to the flow of condensed vapor that precipitates when the pressure drops sharply.

Non-contact magnetometric survey.

The integral express method is a variation of the metal magnetic memory method. It is based on the registration and analysis of the distribution of own magnetic stray fields (SMPR) of products in order to determine the zones of stress concentration, defects, heterogeneity of the metal structure.

VIC.

Conducting visual and measuring control is regulated by the Instruction for visual and measuring control (approved by the resolution of the Gosgortekhnadzor of the Russian Federation dated June 11, 2003 No. 92). For visual-measuring control, special sets of devices are used.

Ultrasonic flaw detection.

Ultrasonic flaw detection - the search for defects in the material of the product by the ultrasonic method, i.e. by emitting and receiving ultrasonic vibrations and further analyzing their amplitude, arrival time, shape, etc.

Ultrasonic thickness measurement.

Ultrasonic thickness measurement is carried out in order to assess the actual value of the wall thickness of structural elements by the method of single measurements in places inaccessible for measuring the thickness with a mechanical measuring tool. Ultrasonic thickness measurement is carried out by the echo-pulse method.

Ultrasonic control (ultrasonic screening).

This method allows you to quickly determine where the problem is on the pipe. The guided wave method used in the inspection is completely different from the methods used in conventional ultrasound methods.

Thermal control.

Thermal imaging inspection is one of the advanced areas of non-destructive thermal imaging control over the state of structures and electrical equipment. Thermal imaging inspection is an effective way to detect defects.

Eddy current method of control.

The eddy current control method is based on the analysis of the interaction of an external electromagnetic

- 1 039461 fields with an electromagnetic field of eddy currents induced by an exciting coil in an electrically conductive test object (OK) by this field.

Electrical control.

Methods for surveying the state of the ECP of underground pipelines are applied. Classification can be carried out on a technological basis - measurements by the methods of electrometric diagnostics of the main gas pipeline itself are made directly above the pipeline.

In-line projectiles.

In-pipe diagnostics of pipelines is based on the use of autonomous flaw detectors (pistons, pigs) moving inside the controlled pipe under the pressure of the pumped product (oil, oil products, gas, etc.). The projectile is equipped with equipment (usually ultrasonic or magnetic).

Acoustic emission (AE).

The AE method is based on the registration and analysis of acoustic waves arising in the process of plastic deformation and fracture (crack growth) of controlled objects. This makes it possible to form an adequate system for classifying defects and criteria for their evaluation.

Radiation control methods.

Radiation control methods are based on the registration and analysis of ionizing radiation when it interacts with a controlled product. The most commonly used methods of control by transmitted radiation, based on different absorption of ionizing radiation.

Magnetic particle method.

The magnetic particle method, among other methods of magnetic control, has found the greatest application due to the ease and simplicity of obtaining the required result.

Remote-controlled diagnostic complex (TDK).

TDK is a remote-controlled diagnostic complex for examining pipelines from the inside. TDK is designed to control pipelines with a diameter of 700-1400 mm. Moving inside the pipe, the robot measures the wall thickness, detects defects in the pipe body and performs visual inspection.

X-ray crawler.

Crawler is an autonomous self-propelled X-ray complex designed to control the quality of welded joints in pipelines. This is a completely independent exposure device that works without wires.

optical control.

The optical range of the spectrum, as defined by the International Commission on Illumination (CIE), is electromagnetic waves, the length of which is from 1 mm to 1 nm. Optical methods are based on the use of reflection phenomena.

penetrating substances.

Capillary testing is also used for objects made of ferromagnetic materials, if their magnetic properties, shape, type and location of defects do not allow achieving the required sensitivity by the magnetic particle method.

Technical endoscopy.

Endoscope (or borescope) is an optical device that is used in visual inspection for various purposes. For example, an endoscope (borescope) is used in engineering to examine hard-to-reach places.

Hardness test.

Hardness testing is a method of non-destructive testing of the hardness of metals, alloys, rubber, plastics, concrete and other materials. Hardness testing is one of the main types of mechanical testing of metal and an effective tool for diagnosing its structural and mechanical state.

Metal magnetic memory method.

The processes preceding operational damage are changes in metal properties (corrosion, fatigue, creep) in stress concentration zones. Accordingly, the magnetization of the metal changes, reflecting the actual stress-strain state of pipelines, equipment and structures.

The main disadvantages of the above methods are the complexity of the devices, the significant cost of diagnostic devices, long-term training of personnel, as well as the impossibility of using corrosion diagnostic methods due to the design features of the object under study or the need to remove the object from the technological process.

Known RF patent for invention No. 2511787, IPC F17D 5/02, Marker for in-line diagnostics. The invention relates to magnetic in-line diagnostics and can be used in the oil and gas industry in determining the coordinates of metal defects in pipes of underground pipelines. The marker consists of two marker pads made of a ferromagnetic material, namely, a pre-magnetized composite material with high plastic properties, installed on the top of the pipeline with a certain distance between them. The marker also contains milestones with an information pointer. The pads are fixed due to the force of the magnetic interaction between the pad and the steel pipe, and a milestone with an information indicator is installed in the ground when the pipeline is backfilled. The technical result is a reduction in the mass of the marker and the complexity of its installation, as well as an increase in the quality of installation and the reliability of its operation.

The disadvantage of this invention is that in order to eliminate the risk of damage to the tag, it is necessary to set an information pointer, such as a checkbox; in addition, during natural disasters (hurricane, hail, etc.), the label can be displaced due to strong mechanical impact.

Closest to the claimed method is the USSR patent for the invention No. 1226171, Method for determining the wear of parts of an internal combustion engine. On the wear surface of a part, such as a piston ring, several marks with different radioactive isotopes are evenly placed. The number of marks, the order of their placement, and the composition of the isotopes are chosen so that the penetration of radiation quanta from neighboring marks through the backs of the collimator can be neglected. Measure the initial intensity of radiation from the isotopes of the labels in the selected intervals and establish their relationship with the thickness of the labels. The determination of the radiation intensity is carried out according to the characteristics of the energy spectra of the radiation of individual isotopes using a radiation analyzer. After that, the engine is operated for a predetermined time. Then the engine is stopped and the piston is set to top dead center. A scanner with a narrow angular collimation is moved above the cylinder head along the trajectory of the marks and the position of one of the marks is set, the isotope of the mark is determined by the type of radiation, and the wear of the piston ring is determined by the change in the total intensity of the mark radiation. Sequentially moving the scanner at known distances, along the trajectory of the movement of the marks, the wear of the piston ring is determined at the locations of the marks.

The disadvantages of this invention are the complexity in hardware design and the limited variety of labels. These methods are costly and labor intensive. Suitable for use in the laboratory, on test benches, but have no use in the field; in addition, radio tags are limited in variety and cannot be used on large products and areas. The need to stop the equipment also creates a big problem.

Disclosure of invention

The objective of the proposed method for monitoring corrosion processes is to create a low-cost, informative, reliable and efficient method for determining the dislocation and propagation rate of corrosion defects in real time, completely protected from the effects of the external environment and requiring a minimum of additional equipment for fixing the mark, while not requiring equipment shutdown.

The problem is solved due to the fact that the method of control of corrosion processes includes the installation of a label, the selection of fluid and the control of indicators. The label is set on the inner surface of the object under study. The label is chosen with the possibility of being applied to a metal surface, ensuring resistance to the working fluid, the absence of analogues in the composition of the working fluid, biological and chemical inactivity with respect to the working fluid and the surface on which the mark is applied, and also ensuring the resistance of the label to barothermic effects. After that, the label is applied to predetermined areas of the object under study. Put into operation, filling with working fluid. After the beginning of the corrosion process, the mark applied to the areas subjected to corrosion, together with particles of metal or an anti-corrosion coating of the areas subjected to corrosion, peel off from the object. Then the mark enters the fluid extraction zone to control the concentration of marks, which determine the presence and interval in which corrosion occurred and the intensity of the corrosion process. Marks of various identification marks are applied to different pre-planned sections of the object. The corrosion rate is determined by the concentration of the number of labels during the study. As a label, fluorescent substances, or indicators of a radical type, or substances with high absorption of thermal neutrons, or radioactive isotopes, or colored substances are chosen. The mark is applied to the maximum area of possible corrosion.

Implementation of the invention

On the inner cavity of the tank of the technological apparatus of tubular products, including at the joints, one of the types of marks is applied, followed by coating it with a protective material. When the protective coating becomes thinner due to the impact of aggressive factors of the working environment, marks (tracer markers) are released. The presence of the interval in which corrosion occurred and its intensity are determined by the content of control marks in the samples of the working fluid. This invention can be used, in particular, to determine the time, extent and localization of the interval of destruction of the protective coating or surface layer;

optimization of costs for maintenance and inspection;

control of hard-to-reach areas subject to corrosion.

Sampling methods.

GOST 2517-2012 Oil and oil products. Sampling methods standardizes methods for sampling from all types of containers, tanks of any kind, road and rail tanks. Equipment is subject to unification, which primarily includes samplers with the specifics of oil products and containers, in particular, stationary ones;

portable;

samplers for sampling liquefied hydrocarbon gases (GOST 14921-78. Liquefied hydrocarbon gases. Sampling methods) and various tanks with pressurized products.

The methodology specifies sampling in vertical, horizontal, ice-ground storages, tanks, incl. hidden underground, in trenches, tankers, tank trucks, etc.

Samples are placed in special bottles that are resistant to aggressive environments, hermetically sealed with a cork or screw cap, wrapped in a dense material for safety, tied with twine, and sealed. The label contains all the required information about the product and the identity of the person taking the sample.

Usually two samples are taken, one of which goes to the laboratory, and the other is stored for arbitration analysis (it is called arbitration). Arbitration analysis can be performed upon presentation of claims on oil quality.

The rules for sampling petroleum products also provide for compliance with safety and fire safety standards, MPE standards (GOST 12.1.005-88. General sanitary and hygienic requirements for air in the working area), sampler materials, the behavior of the sampler according to the instructions, etc.

To implement the method for monitoring corrosion processes, the following types of marks can be used.

Labels (markers-tracers), various substances that differ in the method of identification:

fluorescent substances (rhodamine, sodium fluorescein, eosin disodium salt, erythrosin, etc.), substances used for acid-base titrations of turbid or strongly colored solutions, in which, when illuminated with UV rays and at a certain pH value, it appears (or disappears) ) fluorescence or its color or shade changes;

radical type indicators (urea, ammonia sulfur, stable nitroxide radicals and their derivatives (amines, amine salts)); are used as indicators of compounds from the class of nitrogenous stable nitroxy radicals; widely tested in Tatarstan, Bashkiria at 15 fields (Indicators of a radical type - stable nitroxide radicals, dissolve well in reservoir and injected water, have no analogues in nature, are biologically inactive (environmentally friendly), do not chemically interact with oil, are stable in reservoir conditions, allow you to create a range of indicators with similar physical and chemical properties and a single registration method.As indicators of the radical type, triacetonamine, triacetonamine benzoate, etc. are used.This technology can be used at temperatures not exceeding 70°C.);

substances with high absorption of thermal neutrons (for example, chlorine, radon, solutions of barium salts, boron, cadmium, rare earth elements);

radioactive isotopes, for example, tritium with a long half-life a background measurement of HA is done.The most widely tested is the tritium isotope iodine-131.).

In table. 1 shows the conditions for the applicability of stable labels.

- 4 039461

Table 1

Indicator deposits Conditions of applicability Formation oil composition Mineralization of formation water, kg/m' medium pH Filtration rate, m/day Extreme temperature! cheers, °C Sulfuric acid Terrigenous with a carbonate content of 1-2% the presence of aromatic compounds UP TO 200 less? • 150 Fluorescein Carbonate and terrigenous with clay content not more than 10% up to 250 7-1) >100 170 Uronin Carbonate and terrigenous up to 250 5-10 >100 171) Chloride (sodium chloride) too various oils dose 3-11 various 200 Rhodanite (ammonium thiocyanate) too high content of gasoline fractions, the presence of resins and asphaltenes up to 200 5-10 >4 200 Nntroxyl radicals too up to 250 »00 Triacetone amine hydrochloride too up to 250 >1 70 1 Phosphates (disodium phosphate) Terrigenous with clay content not more than 10% various oils up to 250 5-10 >10 150 Nitrates Carbonate and terrigenous Too up to 300 5-10 various 250

It is also known to use radioactive isotopes as labels in industry. One example of this is the following method for monitoring piston ring wear in internal combustion engines. By irradiating the piston ring with neutrons, they cause nuclear reactions in it and make it radioactive. When the engine is running, particles of the ring material enter the lubricating oil. By examining the level of radioactivity of the oil after a certain time of engine operation, the wear of the ring is determined. Radioactive isotopes make it possible to judge the diffusion of metals, processes in blast furnaces, etc. These labels can also be used as labels for implementing the proposed method.

Applied types of chemical labels (tracer markers) are as follows:

fluorescent tracers;

ion tracers;

organic tracers.

There are color marks, namely color;

glow - chemiluminescent and fluorescent;

marks for the formation of a heterophase (in the particular case - sediment) and changes in its properties - sediment-forming, turbidity and adsorption.

Of these indicators, color labels are most commonly used.

Tags (markers-tracers) are used to identify factors associated with their presence, i.e. to determine the fluid flowing into a specific zone of the mark of ownership of fluids in tanks.

The equipment and technologies for identifying tags are different according to the characteristics of the selected tags.

For example, equipment for determining the presence and concentration of labels of a radical type, fluorescent or color labels use Capillary Electrophoresis Systems KAPEL®-105M.

Capillary electrophoresis CE (Capillary Electrophoresis, CE) is a separation method implemented in capillaries and based on differences in the electrophoretic mobilities of charged particles as in

-5 039461 aqueous and non-aqueous buffer electrolytes. Buffer solutions (leading electrolytes, running buffers, background electrolyte, run buffer) may contain additives (for example, macrocycles, organic solvents, polymers, etc.) that can interact with the analyzed particles and change their electrophoretic mobility.

The main distinguishing feature of the KAPEL®-105M model is spectrophotometric detection. A deuterium lamp is used as a light source, and a diffraction monochromator with a spectral range of 190-380 nm and a spectral interval width of 20 nm is used as a dispersing element. This range makes it possible to select the detection wavelength that is most sensitive to the target components, which facilitates the development of new techniques and, in many cases, reduces the detection limit.

There are also other specialized laboratory instruments and techniques for the determination of selected labels (tracer markers) in substances.

An example of the implementation of the proposed method.

The developers of the method for controlling corrosion processes have carried out tests that prove the industrial applicability of the method.

The tests were carried out in November 2016 at the production base of OOO KomiSeverTranzit. Testing was agreed with KomiSeverTranzit LLC on 11/09/2016.

The equipment for installing test samples was provided by OOO KomiSeverTranzit. Installation of the equipment was carried out by specialists of OOO KomiSeverTranzit.

Tags (markers-tracers) were selected according to the following criteria:

1) unique characteristics to highlight;

2) environmental and sanitary and epidemiological safety;

3) high sensitivity with low material consumption;

4) no chemical reaction with the pumped medium;

5) low cost and availability in the market;

6) the possibility of simultaneous determination of different labels for one sample;

7) the ability to determine markers using available methods of analysis.

As marks, carbamides were chosen, which were deposited on sample 1 (steel pipe with a thread diameter of 73 mm, length 50 cm), and ammonium thiocyanates, which were applied on sample 2 (steel pipe with a thread diameter of 73 mm, length 50 cm).

Sample 1 was installed on the discharge line of the pump located in the pumping room by means of adapter pipes.

Sample 2 was installed at the inlet to the heating radiator located in the storage room by means of adapter pipes.

After the installation of samples 1 and 2, the equipment was put into operation and brought to a permanent mode.

Carbamide (urea) is a label, which is a white fine-crystalline substance. Carbamide crystallizes from water in the form of flat prisms, easily soluble in alcohol and water, melting at a temperature of 160-190°C. When heated to 200°C, this compound turns into ammonium cyanate, and under the influence of higher temperatures at atmospheric pressure, urea decomposes to form carbon dioxide, ammonia, cyanic acid, biuret and other components. Nitrogen is included in the composition of carbamide in an easily digestible amide form. Nitrogen in the amide form is well absorbed by the leaves and roots of plants.

Ammonium thiocyanate is a label that dissolves in ethyl and methyl alcohol, liquid ammonia, acetone. The substance is combustible and when heated above +140°C it turns into thiourea, and at a temperature of +170°C it completely decomposes.

As a protective layer for sample 1 and sample 2, two layers of anti-corrosion coating based on epoxy powder paints were chosen.

The sampling site was determined by a drain cock located in the direction of flow, after the installation sites of samples No. 1, 2. The content of markers was controlled using a KAPEL®-105M capillary electrophoresis system.

Before installation, we additionally measured the flow rate, coolant temperature, and the presence of tracer markers.

Sampling was carried out on the first day every four hours, and on subsequent days once a day.

At the moment when a mark (marker-tracer) appeared in the samples, the fluid pumping was stopped and a visual assessment of the state of the protective layer of the sample, the mark of which was identified, was carried out. After that, the pumping process was started again until the mark of sample 2 appeared. Further, a thorough visual examination of the state of the protective layer on both samples was carried out.

As a result of experimental tests, the following results were obtained, provided in table. 2.

- 6 039461

table 2

Date and time of measurement one 09.11.16 12.00 10.11.16 12:00 10.11.16 16:00 Heh Outlet pressure, atm. 2 5.0 5.0 5.0 schakterist Consumption m ³ / hour 3 1.5 1.5 1.5 IKI Outlet temperature, °C 4 63.0 63.0 63.0 result Presence of a marker: Ammonium urea/r odanides 5 -/- -/- -/- tons of samples Concentration, (particles/litre) K/RA 6 0/0 0/0 0/0 Note _______7 Sample before the OPI. Sample after installation of samples No. 1, 2 10.11.16 20:00 5.0 1.5 63.2 -/- 0/0 11/11/16 0:00 5.0 1.5 62.8 -/- 0/0 11/11/16 4:00 AM 5.0 1.5 62.8 -/- 0/0 11/11/16 8:00 5.0 1.5 63.0 -/- 0/0 11/11/16 12:00 pm 5.0 1.5 63.0 -/- 0/0 12.11.16 12:00 5.0 1.5 63.0 TO/- 11/0 Fixing the presence of a label in the sample (carbamide) The point of destruction of the first layer of the protective coating of Sample No. 1. Stop 13:00. Dismantling. Cavities are visually visible on the inner surface of the sample. Mounting. Start 14:00. 13.11.16 12:00 5.0 1.5 63.0 K/RA 17/30 Increasing the concentration in the sample of the label (urea). Fixing the presence of a label in the sample (ammonium thiocyanate). Destruction point of the first layer of protective coating Sample #2. 14.11.16 12:00 5.0 1.5 63.0 K/RA 25/40 Increasing the concentration of labels from both samples. Sample dismantling. Cavities are visually visible on the inner surface of both samples.

The cost of implementing experimental tests amounted to 18,000 rubles.

- 7 039461

Conclusion

According to the results of experimental tests, it can be seen that the operability of the method for controlling corrosion processes through the use of marks (tracer markers) is fully confirmed.

Thus, potential areas of application are all branches of economic activity in which equipment and materials are used, the internal surface of which is subject to corrosive processes.

The advantages of the proposed method for controlling corrosion processes are as follows: the possibility of localizing the place of corrosion;

the possibility of implementing the method without stopping the equipment for work and without removing the equipment from the process;

possibility of implementation for a wide range of equipment;

the possibility of implementing the method in almost any external and internal environment;

the possibility of more detailed and efficient planning of work to identify corrosion damage, timely repair or replacement;

optimization of operating expenses;

low cost of the method;

the ability to control corrosion processes of engineering networks and process equipment in real time and in places where timely identification of corrosion processes was not available until now.

The task is to create a method for monitoring corrosion processes, as well as a low-cost, informative, reliable and effective method for determining the dislocation and propagation rate of corrosion disturbances in real time, completely protected from the effects of the external environment and requiring a minimum of additional equipment for fixing the mark, while not requiring a stop equipment, completed.

Industrial applicability has been proven by experimental tests conducted by the authors at the production base of OOO KomiSeverTranzit, Usinsk, Komi Republic.

CLAIM

Claims (4)

CLAIM 1. A method for controlling corrosion processes, including applying a label, characterized in that the label is applied to the inner surface of the object under study, and the label is selected with the possibility of applying to a surface subject to corrosion or destruction, and colored and fluorescent substances, or indicators, are selected as the label radical type, or substances with high absorption of thermal neutrons, or radioactive isotopes, moreover, there are no analogues of the specified label in the composition of the working fluid and the label is resistant to the working fluid, biological and chemical inactivity with respect to the working fluid and the surface on which the label is applied, and also resistance to barothermal effects, after which the specified mark is applied to predetermined areas of the object under study, after that the object is put into operation, filling it with a working fluid, and after the corrosion process begins, the mark applied to the areas subjected to corrosion or destruction In addition, the mark, together with particles of the metal or anticorrosion coating that covered the layer with marks, exfoliates from the object, then the mark enters the fluid sampling zone to control the concentration of marks, which determine the presence, the interval in which corrosion occurred, and the intensity of the corrosion process. 2. A method for controlling corrosion processes according to claim 1, characterized in that marks of different identification are applied to different pre-designated sections of the object. 3. A method for controlling corrosion processes according to claim 1, characterized in that the corrosion rate is determined by the concentration of the number of marks during the study. 4. A method for controlling corrosion processes according to claim 1, characterized in that the mark is applied to the maximum area of possible corrosion.