Retardance and low damage acid solution system for high temperature condensate oil gas reservoir acidification

Abstract

The present invention discloses a retardance and low damage acid solution system for high temperature condensate oil gas reservoir acidification. The acid solution system is suitable for acidification modification of high temperature deep well, particularly condensate gas reservoir, and comprises the following components, by weight, 0.5-3 parts of hydrofluoric acid or 6-12 parts of fluoroboric acid, 8-10 parts of an organic ester, 0.01-0.05 part of a catalyst, 0.1-1 part of a corrosion inhibitor, 0.1-1 part of an iron ion stabilizer, 0.1-1 part of a clay stabilizer, 1-2 parts of a cleanup additive, and 80-100 parts of water. According to the present invention, effects of retardance and corrosion inhibition of the acid solution system can be well achieved at a high temperature, and water blocking can be released and acid solution backflow can be easily achieved with the finally produced methanol and the carbon dioxide.

Description

technical field [0001] The invention relates to an acidizing working fluid for oil and gas wells, which is suitable for acidizing reformation of high-temperature condensate oil and gas reservoirs above 120°C. Background technique [0002] Acidizing can effectively remove the damage to the reservoir during drilling and completion operations, restore or improve the formation permeability, and is an important measure to increase the production of oil and gas reservoirs. At present, my country's onshore oilfield development has a trend of high temperature and deep well development. The temperature of the reservoir is getting higher and higher, and the development is becoming more and more difficult. The conventional acid system has a small treatment range, serious secondary damage, and relapse due to the rapid reaction with the rock. Due to the slow discharge rate and fast corrosion rate, it is impossible to effectively realize high-temperature deep well acidizing operations, esp...

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Problems solved by technology

[0004] The main problems of the organic ester acid liquid systems that have been used at present are strong toxicity, poor compatibility, long hydrolysis time, and low hydrolysis efficiency. water lock

Inorganic acid liquid systems in condensate gas reservoirs, such as hydrochloric acid, hydrofluoric acid, and fluoboric acid, react quickly at high temperatures, seriously reducing the acidizing effect, and easily form secondary precipitation under high temperature conditions. The corrosion of the pipe string and other wellsite equipment by the liquid is serious. For the reservoir with difficult flowback, the residual acid flowback is not complete, which will cause serious damage to the reservoir.

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