Corrosion inhibitor for oil and gas wells, and preparation method and application thereof

Abstract

The invention provides a corrosion inhibitor for oil and gas wells, and a preparation method and application thereof. The corrosion inhibitor comprises, by weight (100%), 40 to 60% of an imidazoline derivative, 8 to 40% of organic phosphonate, 30 to 50% of a dispersant and 2 to 15% of a surfactant. The corrosion inhibitor for the oil and gas wells in the invention has high-temperature resistance,stable performance and excellent corrosion inhibition effect, can be used as a broad-spectrum corrosion inhibitor for exploitation in oil and gas fields, and overcomes the shortcomings of conventionalcorrosion inhibitors; the corrosion inhibitor is applicable to crude oil medium environment s in oil well, gas medium environments in gas wells, and water medium environments in water injection wellsin oil fields; and the corrosion inhibitor has good effect on improving the corrosion resistance of metal equipment used in a H2S-CO2-Cl<-> system with high temperature and high salinity during the exploitation of oil and gas wells.

Description

Technical field [0001] The invention belongs to the technical field of oil field development, and relates to a corrosion inhibitor for oil and gas wells, and a preparation method and application thereof. Background technique [0002] Corrosion has always been an important issue limiting the continuous and rapid development of oil and gas fields. Every year, oil and gas exploitation will face crises such as tubing fracture, casing damage, and scrapped oil wells caused by corrosion damage. Especially in recent years, as the corrosive environment of oil and gas fields has become more complicated and worsening (including H 2 S. The increase in water content) has gradually become prominent, and the replacement of equipment materials or surface coatings alone can no longer keep up with the corrosion protection requirements of oil and gas field mining. Therefore, adding corrosion inhibitors, as the most economical, effective, and versatile corrosion protection method, has become a brea...

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Problems solved by technology

However, in practical applications, due to the large amount of H that may be contained in oil wells 2 S and high partial pressure CO 2 In addition, it also contains corrosive Cl - , SO 4 2- , S 2- Plasma and scaling of Ca 2+ , Mg 2+ 、Ba 2+ , these complex and changeable factors make the corrosion inhibition rate of imidazoline corrosion inhibitors in the practical application need to be further improved

Especially the existing corrosion inhibitors for oil and gas wells, such as the corrosion inhibitors mentioned in the patent applications with application numbers CN200610105097.8 and CN200710180019.9, are mostly under low temperature system (2 S / CO 2 It has a good anti-corrosion effect, and the efficiency is greatly reduced due to the hydrolysis of the corrosion inhibitor at high temperature

However, as domestic oil exploitation becomes more and more difficult, most oil fields are now adopting tertiary oil recovery, the drilling depth is more than several thousand meters, and the temperature of oil wells has greatly exceeded 100°C. The existing imidazoline corrosion inhibitors It is difficult to apply to such harsh working conditions. The performance is that the corrosion inhibitor is extremely unstable and decomposes, resulting in a decrease in its corrosion inhibition performance, and the uneven distribution in oil-water mixed oil wells affects the corrosion inhibition effect.

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