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Corrosion inhibitor concentration detection method

A detection method and corrosion inhibitor technology, which is applied in the field of chemical analysis and detection, can solve the problems of inability to accurately measure the actual concentration of low-content corrosion inhibitors, poor ultraviolet absorption of corrosion inhibitors, and low effective concentration of corrosion inhibitors, so as to save manpower The effect of material resources, short time and simple operation

Active Publication Date: 2019-11-19
XIAN UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The evaluation and concentration monitoring of indoor corrosion inhibitors are generally in accordance with the relevant indoor corrosion experiments in GB10124-88 "Metallic Materials Laboratory Uniform Corrosion Full Immersion Test Method" and SY5329-1994 "Recommended Indexes and Analysis Methods for Injection Water Quality of Clastic Reservoirs" However, there is no suitable method for on-site corrosion inhibitor content determination, and the effective concentration and content of corrosion inhibitors are low, which brings great challenges to on-site analysis
Ultra-high performance liquid chromatography (UPLC) is commonly used in the detection of trace substances. However, due to the poor ultraviolet absorption and low sensitivity of most corrosion inhibitors, the application range of UPLC method is very limited, and it cannot accurately determine the content of low-level corrosion inhibitors. actual concentration

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Taking the concentration detection of imidazoline corrosion inhibitor RX-210 in high water injection wells as an example

[0034] Taking the imidazoline corrosion inhibitor RX-210 (molecular weight 584) being used in Changqing Oilfield as an example, the concentration of the corrosion inhibitor is detected by the monitoring method provided by the present invention. The specific steps include: 1) sample preparation; 2) determining chromatographic separation conditions; 3) determining mass spectrometry conditions; 4) measuring the content of optical isomers.

[0035] 1. Sample preparation

[0036] RX-210 uses an automatic downhole dosing device to add medicine. The dosing valve is opened for 3 minutes every 4 hours, and the sample to be tested is taken out from the oil well outlet. The sample to be tested is crude oil with high water content. After standing for 10 minutes, take 100uL of the sample to be tested and add 900μL of methanol , acetonitrile and water in the mix...

Embodiment 2

[0059] Taking concentration detection of corrosion inhibitor RX-210 in produced water as an example

[0060] The crude oil flows into the gathering station through the pipeline, and the crude oil is separated through the three-phase separator. Therefore, the content of corrosion inhibitor in the produced water can guide the dosing frequency of the automatic dosing device.

[0061] Except following conditions, other conditions are identical with embodiment 1:

[0062] ①Take 100 μL of produced water from the three-phase separator and add 1900 μL of methanol, acetonitrile and water into the mixed solution. The volume ratio of methanol, acetonitrile and water in the mixed solution is 1:1:1;

[0063] ② Chromatographic column: ZORBAX RRHD column (50mm*2.1mm*1.8μm);

[0064] ③Mobile phase A (water+0.1% formic acid), B (acetonitrile+0.1% formic acid), 0min 100%A+0%B, 0.5min100%A+0%B; 3min 1%A+99%B, 5min 1 %A+99%B, 5.5min 100%A+0%B, 6min 100%A+0%B); the flow rate is 0.15mL / min;

[...

Embodiment 3

[0071] Taking the concentration detection of corrosion inhibitor PS-10 in reinjection water as an example

[0072] PS-10 is a benzothiazole scale and corrosion inhibitor, the formula is confidential, and the molecular weight of its active ingredient is 167.2. On-site addition is through the dosing pump of the gathering station, and the concentration required by the process is 25-30ppm.

[0073] Except following conditions, other conditions are identical with embodiment 1:

[0074] ①Retrieve 100 μL of water injection, add 1400 μL of methanol, acetonitrile and water mixed solution, the volume ratio of methanol, acetonitrile and water in the mixed solution is 3:2:1;

[0075] ② Chromatographic column: Poroshell120SB-C18 chromatographic column (75mm*4.6mm*2.7μm);

[0076] ③Mobile phase A (water+0.1% formic acid+5mM ammonium acetate), B (acetonitrile+0.1% formic acid), 0min 100%A+0%B, 0.5min 100%A+0%B; 8min 1%A+99 %B, 9min 1%A+99%B, 9.5min 100%A+0%B, 10min100%A+0%B); the flow rat...

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Abstract

The invention belongs to the technical field of chemical analysis and detection, and relates to a corrosion inhibitor concentration detection method. The corrosion inhibitor concentration detection method comprises the following steps of 1) preparing a mixed solution of methyl alcohol, acetonitrile and water, adding a to-be-detected sample containing a corrosion inhibitor into the mixed solution,separating a precipitant by centrifuging, and drying a supernatant obtained by centrifuging to obtain a to-be-analyzed sample containing the corrosion inhibitor; 2) determining ultra performance liquid chromatography and a mass spectrum separation condition; and 3) performing Ultra performance liquid chromatography-mass spectrum / mass spectrum analysis on the to-be-analyzed sample containing the corrosion inhibitor, and calculating concentration of the corrosion inhibitor in the sample by an external standard method. The corrosion inhibitor concentration detection method is simple to operate, is accurate in quantitation, high in sensitivity, short in analysis time and low in mass cost and is particularly suitable for demand of site corrosion inhibitor detection / monitoring, automatic detection can be achieved, and a new idea and a new method for corrosion inhibitor concentration detection are provided.

Description

technical field [0001] The invention belongs to the technical field of chemical analysis and detection, and relates to a method for detecting the concentration of a corrosion inhibitor. Background technique [0002] In the process of crude oil extraction, scaling, corrosion, waxing and other phenomena in the downhole are prominent, which have a serious impact on the output of crude oil and the maintenance time of the oil well. Therefore, adding chemicals to the oil well to achieve corrosion inhibition, wax prevention, and viscosity reduction The effect is to delay the stable production cycle of crude oil and improve economic benefits. [0003] At present, the dosing methods in domestic oilfields mainly include manual dosing, continuous automatic dosing and downhole pulse dosing. With the improvement of the modernization of oilfield exploitation, centralized automatic dosing devices are being used on a large scale. However, due to the mechanism of corrosion inhibition and th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N30/02
CPCG01N30/02
Inventor 陈福欣李侃社吴燕赵伟邹芳汪广恒李振陈创前周安宁
Owner XIAN UNIV OF SCI & TECH