GB/T 35509-2017 Application and evaluation of corrosion inhibitors in oil and gas fields GB/T35509-2017 |tt||Standard compression package decompression password: www.bzxz.net
This standard specifies the evaluation method and field application of corrosion inhibitors for surface gathering and transportation systems in oil and gas fields. This standard is applicable to the screening, evaluation and application of corrosion inhibitors for surface gathering and transportation systems in oil and gas fields.

ICS25.220.99
National Standard of the People's Republic of China
GB/T35509—2017
Application and evaluation of corrosion inhibitors in oil and gas fields2017-12-29Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of ChinaStandardization Administration of China
2018-07-01Implementation
GB/T35509—2017
Normative references
Terms and definitions
Performance indicators
Field application
8 Documents and preservation
Appendix A (Normative Appendix)Determination of static corrosion inhibition rate by laboratory high temperature and high pressure immersion methodAppendix B (Normative Appendix) ）Determination of dynamic corrosion inhibition rate by laboratory high temperature and high pressure immersion method Appendix C (normative appendix)
Determination of static corrosion inhibition rate by laboratory high temperature and high pressure electrochemical method: Appendix D (normative appendix)Determination of dynamic corrosion inhibition rate by laboratory high temperature and high pressure electrochemical method Appendix E (informative appendix)
Field application of corrosion inhibitor
Appendix F (normative appendix)
References
Methods for removing corrosion products
This standard was drafted in accordance with the rules given in GB/T1.1-2009. This standard was proposed by the China Petroleum and Chemical Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Anti-Corrosion (SAC/TC381). GB/T35509—2017
The drafting units of this standard are: Shenyang Zhongke Corrosion Control Engineering Technology Co., Ltd., Shenyang Zhongke Surface Engineering Technology Co., Ltd., China International Corrosion Anti-Corrosion Technology Research Institute (Beijing) Co., Ltd., China National Petroleum Corporation Tarim Oilfield Branch, China Petrochemical Corporation Northwest Oilfield Branch, China Petrochemical Corporation Zhongyuan Oilfield Branch, Beijing Bihaizhou Corrosion Protection Industry Co., Ltd., China Industrial Anti-Corrosion Technology Association, Xinjiang Zhongzhong Tongxing Anti-Corrosion Technology Co., Ltd. The main drafters of this standard are: Zang Hanyu, Chen Jiajian, Jin Wei, Wang Guiming, Kong Wei, Wang Fengping, Chang Zeliang, Li Mingzhi, Zhang Zhihong, Huang Xuesong, Xie Junfeng, Song Wenwen, Di Jianjun, Li Yixuan, Liu Qiang, Chen Bo, Xu Jizhuan, Liu Yan, Liu FuyuniKAoNi KAcabzxZ.net
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1 Scope
Application and evaluation of corrosion inhibitors in oil and gas fields
This standard specifies the evaluation method and field application of corrosion inhibitors for surface gathering and transportation systems in oil and gas fields. This standard is applicable to the screening, evaluation and application of corrosion inhibitors for surface gathering and transportation systems in oil and gas fields. 2 Normative references
GB/T35509—2017
The following documents are indispensable for the application of this document. For all dated references, only the dated version applies to this document. For any undated referenced documents, the latest version (including all amendments) shall apply to this document GB/T 2481.1 Detection and marking of abrasive particle size composition for bonded abrasives Part 1: Coarse abrasive particles F4~F220 GB/T 3535 Pour point determination of petroleum products
GB/T 6324.1 Test methods for organic chemical products Part 1: Water miscibility test for liquid organic chemical products SY/T 5273-2014 Performance indicators and evaluation methods of corrosion inhibitors for oilfield produced water treatment ASTM G170-2012 Standard Guide for Evaluating and Qualifying Oilfield and Refinery Corrosion Inhibitor the Laboratory 3 Terms and definitions
The following terms and definitions apply to this document. 3.1
Oil-gas gathering and transferring system
oil-gas gathering and transferring system gathers the oil, associated natural gas and other products produced by scattered oil wells, and after necessary treatment and preliminary processing, transports qualified oil and natural gas to refineries and natural gas storage stations respectively. The general term for the pipelines, storage tanks, other equipment and other facilities involved in the whole process.
Corrosion inhibitor
Chemical substances that exist in the corrosion system at an appropriate concentration and do not significantly change the properties and concentration of the corrosive medium, but can significantly reduce the corrosion rate.
Pour point
The lowest temperature at which oil products can flow when cooled under specified conditions. 3.4
Oil produced water
Water containing crude oil produced during the oil field exploitation process. 3.5
Inhibition efficiency
The percentage of the difference between the corrosion rate without corrosion inhibitor and the corrosion rate with corrosion inhibitor added and the corrosion rate without corrosion inhibitor added.
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GB/T35509—2017
Maximum pit depthmaximumpitdepth
The vertical distance between the bottom of the pit with the maximum pit depth on the corroded metal surface and its original surface. 3.7
rotating cylindrical cage
rotating cage
A hanging device used in immersion corrosion test, which can obtain a higher flow rate than the simple stirring method. 3.8
rotating disk electrode
rotating disk electrode
An electrochemical test working electrode used in corrosion evaluation test that can simulate different flow rates and different flow states (laminar flow, eddy current, flow).
4 Performance indicators
The selection of corrosion inhibitors should be based on various factors affecting corrosion, the physical and chemical properties of the corrosion inhibitors and the conditions of use, and should be determined according to the following items 4.1
:
The causes and types of corrosion;
The types of metals and the working conditions of the corrosive environment; b)
Whether the corrosion inhibitor protective film has a lasting protective effect; whether it is easy to store, transport, use and inject; and the possible harmful effects on subsequent processes. The performance indicators of liquid corrosion inhibitors used in oil and gas gathering and transportation systems shall comply with the requirements of Table 1 Table 1 Physical and chemical performance indicators of corrosion inhibitors
Solubility
Emulsification tendency
Compatibility
Corrosion inhibition rate
5 Evaluation
5.1 Basic requirements
Uniform liquid
≤-10℃
Water-soluble oil dispersion or oil-soluble water dispersion
No emulsification tendency
Does not reduce the performance of itself and other agents
Immersion method static and dynamic uniform corrosion inhibition rate ≥70%Immersion method static and dynamic pitting corrosion inhibition rate ≥60%Electrochemical method static and dynamic corrosion inhibition rate ≥80%
（ When evaluating the effect of corrosion inhibitors, the actual concentration of the product shall be used as the basis) Evaluation method
GB/T3535
GB/T6324.1
SY/T5273—2014
SY/T5273—2014
Appendix A, Appendix B,
Appendix C, Appendix D
5.1.1 The performance of the manufacturer's corrosion inhibitor products shall comply with the requirements of Table 1 and shall have a product quality certificate and quality inspection report. 5.1.2 Before the corrosion inhibitor is used in the oil and gas field, the manufacturer shall provide samples. Such samples shall be inspected by a qualified third-party inspection agency and can only be used after meeting the requirements.
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2 Sampling rules
GB/T35509—2017
5.2.1 Randomly sample the corrosion inhibitor samples submitted for inspection, 2 barrels for less than 10 barrels, 4 barrels for less than 50 barrels, 6 barrels for 50 barrels or 100 barrels, and 8 barrels for more than 100 barrels; mix the selected samples to make them uniform and divide them into two parts, each of which is not less than 500mL; one part is submitted for inspection and the other part is kept for reference. The retention period is three months
5.2.2 The samples should be packaged in clean plastic bottles, sealed, labeled and marked with relevant information as required. 5.3 Evaluation method
5.3.1 Appearance
Visual inspection.
5.3.2 Pour point determination
Perform according to the provisions of GB/T3535.
5.3.3 Solubility test
Perform in accordance with the provisions of GB/T6324.1.
5.3.4 Emulsification tendency determination
Perform according to the provisions of 4.5 of SY/T5273-2014. 5.3.5 Compatibility test
Perform according to the provisions of 4.10 of SY/T5273-2014. 5.3.6 Corrosion inhibition rate
The experimental method for evaluating the corrosion inhibition rate of corrosion inhibitors by indoor static high temperature and high pressure immersion method is shown in Appendix A; the experimental method for evaluating the corrosion inhibition rate of corrosion inhibitors by indoor dynamic high temperature and high pressure immersion method is shown in Appendix B; the experimental method for evaluating the corrosion inhibition rate of corrosion inhibitors by indoor static high temperature and high pressure electrochemical method is shown in Appendix C; the experimental method for evaluating the corrosion inhibition rate of corrosion inhibitors by indoor dynamic high temperature and high pressure electrochemical method is shown in Appendix D; 6 Acceptance
Acceptance shall be carried out in accordance with the following requirements:
After inspection, the product fully meets the requirements of Table 1 and is a qualified product. a)
In the test results, if one of the indicators of the product does not meet the requirements, the same product can be re-tested. If all indicators meet the requirements, the batch of products is considered qualified. If there are still non-compliant items in the second test, the batch of products is unqualified. c
The user should accept the product according to the inspection rules and test methods specified in this standard within 20 days after receiving the product. 7 On-site application
For details, please refer to Appendix E.
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GB/T35509—2017
Document and preservation
The test report, test record, test report involved in the evaluation of corrosion inhibitors, and the filling plan involved in the application of corrosion inhibitors and other related materials need to be archived and preserved for 3 years.
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A.1 Test principle
Appendix A
(Normative appendix)
Determination of static corrosion inhibition rate by laboratory high temperature and high pressure immersion method GB/T35509—2017
The average corrosion rate, pitting corrosion rate and corrosion inhibition rate are calculated based on the mass loss of the test piece suspended in the test water sample before and after the test. A.2 Test equipment and instruments
The test equipment and instruments are as follows:
High temperature and high pressure reactor, working temperature: 0℃～200℃ (soil 1℃); working pressure: 0MPa～20MPa (soil 0.1MPa) a)
Analytical balance: accuracy 0.1mg.
Vernier caliper: accuracy 0.02mm.
Dissolved oxygen tester: range 0mg/L～19.99mg/L, 0℃~50℃. e)
Electric hair dryer.
Chemical reagents and gases
Chemical reagents and gases are as follows:
Petroleum ether: analytical grade, boiling range: 60℃~90℃. a
Anhydrous ethanol: analytical grade.
Nitrogen: high-purity nitrogen, purity not less than 99.999%. d)
Carbon dioxide gas: food grade, purity not less than 99.99%Hydrogen sulfide gas: purity not less than 99.9%. f)
Corrosion product cleaning solution (see Appendix F for corrosion product removal method). A.4 Test medium
Fresh oilfield produced water is recommended as the test medium for corrosion inhibitor evaluation and screening. If it is not possible to use on-site oilfield produced water, use prepared simulated oilfield water (prepared with reagents that meet the requirements and distilled water according to the actual water quality and main ion components on site, so that the self-prepared simulated water sample simulates the on-site produced water to the greatest extent). A.4.2 The water sample should be prepared before use, and sufficient water samples should be kept. The same batch of tests can only use the water sample prepared at the same time. A.4.3 The prepared water sample is generally driven by nitrogen for 12h to 14h until the dissolved oxygen content in the water meets the on-site requirements. The dissolved oxygen content in the water can be tested in real time using a dissolved oxygen tester, and the concentration is required to be controlled below 5×10-°, preferably below 1×10-\. A.4.4 For the carbon dioxide corrosion system, carbon dioxide gas is introduced into the simulated oilfield water; for hydrogen sulfide corrosion, hydrogen sulfide gas is introduced into the simulated oilfield water; for the corrosion system of carbon dioxide and hydrogen sulfide mixture, carbon dioxide and hydrogen sulfide mixed gas are introduced into the simulated oilfield water.
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GB/T35509—2017
A.5 Test piece
A.5.1 Test piece material
The test piece material should be the same as the steel actually used in the oil and gas field. The material for processing the test piece should be taken from the metal pipe or plate that has not been used after leaving the factory.
A.5.2 Preparation of test pieces
The preparation of test pieces should comply with the provisions of 4.7.5.2 of SY/T5273-2014. The shape of the test piece should be a rectangular parallelepiped with an outer dimension of 50mm×10mm×3mm. Drill a small hole with a diameter of 6mm in the middle position 5mm away from the edge line at one end, and print the steel number. The shape, specification and surface roughness of the test pieces in the same batch of tests should be the same, and the roughness of the inner ring surface of the center hole of the same test piece should be consistent with the roughness of other surfaces of the test piece. The test piece is planed and ground to make its surface roughness Ra=1.6μm. A.6 Test conditions
A.6.1 Test temperature and pressure: Determined according to the actual temperature and pressure of the corrosion inhibitor used on site. A.6.2 Test cycle: The evaluation cycle of corrosion inhibitors for oil and gas gathering and transportation is generally 7d. A.6.3 Test simulated water dosage: not less than 20mL for every 1cm test piece surface area. A.7 Test steps
A.7.1 Wipe the test piece with filter paper first, then put it in a container containing petroleum ether, remove the grease on the surface of the test piece with absorbent cotton, and then soak it in anhydrous ethanol for 5 minutes for further degreasing and dehydration. Take out the test piece and place it on the filter paper. After drying with cold air, wrap the test piece with filter paper and place it in a desiccator. Weigh it after 24 hours, and the mass is accurate to 0.1mg. A.7.2 Measure the size of the test piece with a vernier caliper, accurate to 0.02mm, and calculate the surface area of ​​the test piece according to formula (A.1). 2nd”+dh
S=2（l+lh+wh）
Where: l, w, h, d are the length, width, thickness and hole diameter of the test piece, respectively, in mm....
....(A. )
A.7.3 Fix the prepared test piece on the test piece holder. The fixing device of the test piece should avoid crevice corrosion. The test piece is not allowed to contact with the container wall. The distance between the test pieces should be more than 1cm. The upper end of the test piece should be more than 3cm from the liquid surface. Three parallel samples should be made for each test. A.7.4 Prepare a simulated test solution containing a certain concentration of corrosion inhibitor in a volumetric flask according to the test requirements, and transfer the prepared test solution containing corrosion inhibitor to the autoclave, and then use nitrogen to drive oxygen for 1 hour. At the same time, measure the pH value of the test solution. A.7.5 Carefully place the autoclave cover on the autoclave body in a fixed position and tighten the main nut. It should be tightened symmetrically in multiple times and evenly. Do not allow the autoclave cover to tilt to one side to achieve good A.7.6 After installing the autoclave, connect the nitrogen cylinder and the autoclave air inlet valve, and keep the air inlet valve in the open state and the air outlet valve in the closed state. Pass nitrogen into the autoclave. When the pressure in the autoclave reaches 2MPa, stop pressurizing. At the same time, close the cylinder valve and the autoclave air inlet valve, and check whether the autoclave is leaking. After 3 minutes, open the air outlet valve to exhaust the mixed gas in the autoclave. After exhausting, close the air outlet valve.
A.7.7 Open the air inlet valve, pass nitrogen into the autoclave. When the pressure in the autoclave reaches 2MPa, stop venting. At the same time, set the test temperature, turn on the heating switch on the controller to heat up the autoclave. A.7.8 Wait until the temperature of the solution in the autoclave reaches After the test reaches the preset temperature, the test gas (such as HS, CO) is introduced into the autoclave to the specified partial pressure. After stabilization for 10 minutes, if the pressure drops, pressurize the autoclave again, and repeat this process until the pressure stops dropping. Finally, nitrogen is introduced into the autoclave to make the pressure reach the preset total pressure of the test, and the test begins. A.7.9 After the test, when the temperature inside the autoclave drops to room temperature, the mixed gas in the autoclave is released. When the pressure drops to normal pressure (the pressure gauge shows zero), remove the cap and place it on the bracket. At the same time, measure the pH value of the solution after the test. GB/T35509—2017
A.7.10 Take out the test piece that has reached the test cycle, observe, and record the surface corrosion morphology. , immediately rinse with clean water and wipe dry with filter paper. A.7.11 Place the test piece in a container filled with petroleum ether, remove the oil on the surface of the test piece with absorbent cotton, take out the test piece and soak it in the corrosion product cleaning solution prepared in Appendix A for 5 minutes, and gently wipe the corrosion products on the surface of the test piece with absorbent cotton; take out the test piece from the cleaning solution, rinse the residual cleaning solution on the surface with tap water, and then place it in anhydrous ethanol for dehydration. Take out the test piece and place it on the filter paper, blow it dry with cold air, then wrap the test piece with filter paper, store it in a desiccator, and weigh it after 12 hours, accurate to 0.1mg. A.7.12 If there are pits on the surface of the test piece, measure its depth and record it, A.8 Representation and calculation of test results
A.8.1 Calculation of corrosion rate: The average corrosion rate is calculated by the weight loss of the test piece before and after the test, and the pitting corrosion rate is calculated by the maximum pitting depth, so as to understand the corrosion of the test solution on the test piece before and after the addition of the drug. The specific calculation process is carried out according to the following requirements: Calculate the uniform corrosion rate r according to formula (A.2). : a
Where:
8.76 X10*X (mm)
Uniform corrosion rate, in millimeters per year (mm/a): The mass of the test piece before the test, in grams (g); The mass of the test piece after the test, in grams (g); The surface area of ​​the test piece, in square centimeters (cm); The density of the test piece material, in grams per cubic centimeter (g/cm): Experimental time, in hours (h).
b) Calculate the pitting corrosion rate rp according to formula (A.3): 8.76×10°×h
Where:
pitting corrosion rate, in millimeters per year (mm/a); the maximum pitting depth on the surface of the test piece after the test, in millimeters (mm): test time, in hours (h).
A.8.2 Calculate the uniform corrosion inhibition rate n1 according to formula (A.4): 1
Where:
Inhibition rate:
ro-r×100%
The uniform corrosion rate of the blank test, in millimeters per year (mm/a); the uniform corrosion rate of the test with the addition of corrosion inhibitor, in millimeters per year (mm/a). A.8.3 Calculate the pitting corrosion inhibition rate n2 according to formula (A.5): 2
Where:
pitting corrosion inhibition rate;
Ah. -Ahi
The deepest pitting depth on the surface of the test piece in the blank test, in millimeters (mm); the deepest pitting depth on the surface of the test piece in the test with corrosion inhibitor added, in millimeters (mm). (A.2)
.(A.4)
.(A.5)
GB/T35509—2017
B.1 Test Principle
Appendix E
(Normative Appendix)
Determination of Dynamic Corrosion Inhibition Rate by Laboratory High-speed Dynamic Corrosion Test Reactor The corrosion test is carried out under the required working conditions (temperature, pressure and flow rate) using a high-speed dynamic corrosion test kettle. The uniform corrosion rate, pitting corrosion rate and corrosion inhibition rate are calculated based on the mass loss of the test piece fixed on the rotating cage before and after the test. The ASTMG170-2012 standard points out that the experimental device for evaluating corrosion inhibitors under dynamic conditions should be able to grasp the comprehensive parameters that dominate the corrosion rate, rather than blindly striving to reproduce all environmental conditions on site. Under the on-site medium flow conditions, the comprehensive fluid dynamics parameters that dominate corrosion are wall shear stress and Reynolds number. According to the fluid similarity criterion, as long as the wall shear stress is the same, it can be considered that the fluid hydrodynamic state of the simulation experiment and the on-site fluid is the same, that is, the corrosion rate and corrosion inhibition effect of the corrosion inhibitor measured in the laboratory can represent the service effect under the on-site dynamic conditions.
Under the on-site medium flow conditions, the dynamic parameters of the fluid in each component (such as round pipes, elbows, tees, etc.) The wall shear stress T is recommended to be calculated using mature fluid mechanics software. Before that, the kinematic viscosity, average flow velocity, density and component specification parameters of the on-site fluid must be provided.
The wall shear stress T of the rotating cage of the fixed test piece used in the laboratory to simulate dynamic conditions. Calculate according to formula (B.1): to = 0.0791Re-0.3prc2.3
Where:
Re Reynolds number, Re = wr2/v (a is angular velocity. r is the radius of the rotating cage, and is kinematic viscosity); 0
medium density, in grams per cubic centimeter (g/cm2); R is the radius of the rotating cage, in meters (m). . (B.1)
When the wall shear force of the on-site fluid is equal to the wall shear force of the rotating cage, that is, three t. When, calculate the angular velocity w of the rotating cage, and at the same time calculate the rotation linear velocity and number of revolutions of the rotating cage in combination with the radius R. B.2 Test equipment and instruments
The test equipment and instruments are as follows:
High-speed dynamic corrosion test kettle, the hanging device is a rotating cage (see Figure B.1). Working temperature: 0℃～200℃ (soil 1℃); working pressure: 0MPa~20MPa (±0.1MPa). Analytical balance: accuracy 0.1mg. Vernier caliper: accuracy 0.02mm. Dissolved oxygen tester: range 0mg/L~19.99mg/L, 0℃~50℃. Electric hair dryer. Corrosion product cleaning solution (see Appendix F for corrosion product removal method).99mg/L, 0℃~50℃. Electric hair dryer.
Corrosion product cleaning solution (see Appendix F for corrosion product removal methods).99mg/L, 0℃~50℃. Electric hair dryer.
Corrosion product cleaning solution (see Appendix F for corrosion product removal methods).
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