Multi-hydrogen acid system suitable for reservoir plugging-removing acidification and preparing method thereof

Abstract

The invention belongs to a multi-hydrogen acid system suitable for reservoir plugging-removing acidification and a preparing method thereof. The multi-hydrogen acid system is prepared from, by weight,30-60 parts of hydrochloric acid, 7-12 parts of multi-hydrogen acid, 3-6 parts of a multipurpose additive, 2-4 parts of a shrinking agent, 1-3 parts of an activating agent, 3-8 parts of an initiatingagent, 2-4 parts of a corrosion inhibitor and 3-52 parts of water; the hydrochloric acid is selected from industrial hydrochloric acid with the HCL content of 28% to 31%; the multi-hydrogen acid is selected from one of citric acid, phosphoric acid, oxalic acid and sulfuric acid or a mixture of citric acid, phosphoric acid, oxalic acid and sulfuric acid; the multipurpose additive is a mixture of afluorocarbon surfactant, potassium amine triacetate, potassium chloride and water; the activating agent is selected from one of a demulsifying agent AE1910, a demulsifying agent 1031 and polyethenoxyether or a mixture of a demulsifying agent AE1910, a demulsifying agent 1031 and polyethenoxy ether; the initiating agent is peracetic acid. The multi-hydrogen acid system has the advantages that theacid liquor activity, H+ mild releasing and the buffering effect are achieved, and the multi-hydrogen acid system is suitable for reservoir plugging-removing acidification.

Description

technical field [0001] The invention belongs to the technical field of acidizing fluid for increasing production and injection of oilfield reservoirs, and in particular relates to a polyhydric acid system suitable for plugging removal and acidizing of reservoirs and a preparation method thereof. Background technique [0002] In oil and gas exploration and development, acidizing is widely used in the reservoir stimulation of oil wells, water wells and natural gas wells to achieve the purpose of increasing oil and gas production and increasing water injection. At present, many composition systems have been used for reservoir acidification transformation. Among these composition systems, most of them are based on hydrochloric acid and the mixture of hydrochloric acid and hydrofluoric acid. These acid solutions have strong acid activity, fast corrosion speed and good effect. characteristics, but it is not conducive to the deep corrosion of acid liquid. Although some acid liquid ...

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Problems solved by technology

At present, many composition systems have been used for reservoir acidification transformation. Among these composition systems, most of them are based on hydrochloric acid and the mixture of hydrochloric acid and hydrofluoric acid. These acid solutions have strong acid activity, fast corrosion speed and good effect. characteristics, but it is not conducive to the deep corrosion of acid liquid. Although some acid liquid systems have achieved a certain slowing effect by adding various additives on the basis of the original hydrochloric acid and the mixture of hydrochloric acid and hydrofluoric acid, it is still difficult to Meet the needs of deep formation plugging removal

In recent years, Chinese patent applications have disclosed some polyhydric acid systems for the purpose of retardation. These systems are generally based on polymeric polybasic acids and acid anhydrides. These systems can indeed play a role in deep acidification, but due to acid Weaker, the treatment effect on the near-wellbore area is weak, which has certain shortcomings for some wells with severe blockage and difficult injection, such as slow pressure drop, long time for plugging effect, and long construction time.

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