Oil displacement micro-lactic acid system for acidizing and plugging removal and preparation method thereof

Abstract

The invention provides an oil displacing microemulsified acid system for acidizing plugging removal and a preparation method of the system. The oil displacing microemulsified acid system is prepared from the following components in percentage by weight: 10-35% of diesel fuel, 40-75% of acid fluid, 10-30% of alkylsulfobetaine, 1-15% of fatty amine polyoxyethylene ether phosphate, and the balance of 10% hydrochloric acid. The preparation method of the system comprises the following steps: weighing the raw materials by weight; firstly, putting acid fluid into a vessel, heating and stirring in water bath at 60 DEG C, adding alkylsulfobetaine and fatty amine polyoxyethylene ether phosphate for dissolving thoroughly, and then adding 10% ydrochloric acid; and next, adding the diesel oil and stirring for 0.5 hour, thereby obtaining the finished product. The oil displacing microemulsified acid system is a thermodynamic stable system, has excellent dissolving property to inorganic matters and organic matters, and excellent oil displacing property, and can be widely applied to the measures of a water injection well and an oil well conversion well.

Description

technical field [0001] The invention relates to the field of oil field chemical agents for oil exploitation, in particular to an oil displacement microlactic acid for acidification and plugging removal and a preparation method thereof. Background technique [0002] Water flooding and chemical flooding are important oil recovery methods in the process of oil production, which are called "2+3" oil recovery by experts at home and abroad. For medium and low permeability reservoirs that are clogged by inorganic and organic substances during water injection, acidification is usually used to remove plugging measures. Because conventional acid systems, such as hydrochloric acid and soil acid, have too fast acid-rock reaction and cannot complete deep plugging removal, retarded acid systems are usually used. Microlactic acid systems are a new type of retarded acid systems developed on the basis of microemulsions. It is a microemulsion spontaneously formed mainly by acids, oils and sur...

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Problems solved by technology

[0003] There are following problems in the microlactic acid system of prior art: Poor thermal stability, easy to demulsify above 70°C; Cationic or Gemini cationic surfactants are used as surfactants, which are prone to strong adsorption in the reservoir, resulting in rapid destruction of the microemulsion system and premature release of acid; The acid used is hydrochloric acid or earth acid, both of which are strong acids and cannot complete acidification and blockage removal in deep or ultra-deep parts; There is still residual oil in the seepage channels of water flooding, which affects the water injection pressure and injection volume, and requires residual acid to have oil displacement performance

[0004] No useful diesel oil, polyhydric acid or organic tartaric acid, alkyl sulfonate betaine, fatty amine polyoxyethylene ether phosphate, hydrochloric acid has been found A report on preparation of oil displacement microlactic acid by mixing

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