In the article experience of use of monocarboxylic acid in oil well treatment are reviewed. Noted range of advantages of monocarboxylic acid compared to usually used hydrochloric acid solutions. Main advantages are: slower rate of interaction with carbonate matrix; lower corrosion rate; better iron and aluminum ions stability features. Monocarboxylic acid can be used as additives to hydrochloric acid solutions at oil well treatments (acetic acid, formic acid etc.).
To optimize cost of treatments we tested out hydrocarbon liquid-phase oxidation products (hereafter referred to as ‘mono-mix’) - mixture of monocarboxylic acids and organic solvents. Production of mono-mix is well spread at gasoline plants or in situ at oil fields treating facilities. Mono-mix manufactured from co-produced gas or gas and condensate from gas fields. To define reservoir condition limitation for mono-mix well treatment series of laboratory tests was conducted. It is shown that mono-mix reaction with carbonate is exothermic. Neutralization rate of mono-mix as well as it`s solutions with HCl considerably slower compared to pure HCl. Mono-mix solutions (fresh or spent) bear low coefficient of surface tension at mono-mix – oil border. Mono-mix shows quite high stabilizing and bactericidal features. Fresh and spent mono-mix solutions significantly depress the swelling ability of formation clays as well as filtered from drilling mud, destroy and disperse clay structure supporting the takeaway from the reservoir, possessing anti-corrosion features.
Using theoretical and experimental data one-fluid and two-fluids solutions for field testing proposed. 11 oil well exploiting Kashirskian-Podolskian horizon of Arlanskoye oilfield were treated with mono-mix solution. Before pilot test those wells were treated with HCl numerous times as well as with oil-acid emulsion.
Treatment with mono-mix solutions complete in pilot test display much better result compared to previous standard HCl-solution treatments and can be recommended for common use.
References
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