Salt tolerant corrosion and scale inhibitor for underground oil-gas wells and preparation method thereof

Abstract

The invention relates to a salt tolerant corrosion and scale inhibitor for underground oil-gas wells and a preparation method thereof. The salt tolerant corrosion and scale inhibitor is composed of an oxazoline derivative, thiourea, cetyl pyridinium chloride, dodecyl dimethyl benzyl ammonium chloride, amino trimethylene phosphonic acid, hydroxyethylidene diphosphonic acid, hexamethylenetetramine, and methanol. The corrosion and scale inhibitor has very strong salt resistance, and under high salinity conditions (100000-200000mg / L), has a significant inhibiting effect on metal corrosion, and the corrosion inhibition rate can reach more than 80%. The organic phosphonic acid molecular structure of the reagent contain a double bond structure, the structure and the calcium ions and magnesium ions in water can chelate to form a stable complex to be adsorbed on seed crystal surface active sites, thereby inhibiting crystal normal growth. With significant scale inhibiting effect and a scale inhibiting rate up to 94%, the product is suitable for inhibiting corrosion and scaling phenomena of oil-gas well rods and pipes containing carbon dioxide, hydrogen sulfide and other complex media conditions under high salinity.

Description

technical field [0001] The invention relates to the field of anticorrosion of oil production equipment in oil fields, in particular to a salt-resistant corrosion and scale inhibitor used for oil and gas downhole pipe strings and a preparation method thereof. Background technique [0002] At present, the formation water in the production medium of some oil wells in the oil field has high salinity, high content of chloride, calcium, magnesium and other ions, and contains H 2 S, CO 2 Corrosive gas, low pH value, this produced liquid has a strong tendency of corrosion and scaling, resulting in frequent corrosion and scaling of rods and pipes. This brings huge economic losses to the production and operation of oil and gas wells, and becomes a hidden danger to the normal production of oil fields. [0003] Anti-corrosion and anti-scaling technologies are often used in oil fields, including: cathodic protection, spraying organic coatings, and dosing chemicals. Among them, the che...

AI Technical Summary

Problems solved by technology

However, for oil and gas wells, H 2 S, CO 2 Acid gas, as well as a variety of complex corrosion and scaling substances, often cannot achieve satisfactory anti-corrosion and anti-scaling effects

[0006] On-site use of a single agent for oil well corrosion and scaling protection can neither solve the problem of coexistence of on-site corrosion and scaling, but also increase production costs and workload, and there are potential problems of incompatibility between agents

The anti-corrosion and scale inhibitors developed by oilfields such as Huabei and Shuanghe for the reasons of oil well corrosion and scaling have achieved remarkable results in field application, but they are mostly used for the prevention and control of oil wells with a salinity of less than 100,000 mg / L and above 100,000 mg / L. no significant effect

This is mainly because under the condition of high salt content, the existing corrosion inhibitors cannot form an effective protective film, and the protective performance on metals is not strong.

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