Encapsulated solid acid, preparation and applications thereof

A solid acid, encapsulation technology, applied in chemical instruments and methods, drilling compositions, etc., can solve the problems of short action time, inability to ensure acid-liquid binding, poor construction effect, etc. The release rate and the effect of easy on-site construction

Active Publication Date: 2017-03-08
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, according to the research, it is found that this technology cannot guarantee the effective combination of the two acid solutions in the formation when the two-liquid method is injected into the formation, and it is difficult for the nitric acid p

Method used

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  • Encapsulated solid acid, preparation and applications thereof
  • Encapsulated solid acid, preparation and applications thereof
  • Encapsulated solid acid, preparation and applications thereof

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0058] Example 1: Preparation of encapsulated solid acid by coating dry nitric acid powder with chitosan by solvent evaporation method.

[0059] (1) Disperse nitric acid powder and polymer stabilizer in an organic solvent to obtain solution A;

[0060] (2) Stir and mix the material of the capsule wall and water evenly with a stirrer at a speed of 1000-2000r / min to prepare solution B;

[0061] (3) Mix solutions A and B slowly at a volume ratio of 25:1 to form an emulsion, and at the same time, heat to 30-50°C and stir for 2-5 hours to form a white emulsion;

[0062] (4) Centrifuge the emulsion at a speed of 2000-3000r / min for 30 minutes to obtain a precipitate, and then place the precipitate at minus 70°C and a pressure of 0.01-0.005 Pa for 5-10 hours for freeze drying to obtain Encapsulated solid acid with a particle size of 20-45μm and a mass ratio of the capsule wall to the capsule core of 3:7.

Example Embodiment

[0063] Example 2: Preparation of encapsulated solid acid by coating dry nitric acid powder with chitosan by solvent evaporation method.

[0064] (1) Disperse nitric acid powder and polymer stabilizer in an organic solvent to obtain solution A;

[0065] (2) Stir and mix the material of the capsule wall and water evenly with a stirrer at a speed of 1000-2000r / min to prepare solution B;

[0066] (3) Mix solutions A and B slowly at a volume ratio of 15:1 to form an emulsion, and at the same time, heat to 30-50°C and stir for 2-5 hours to form a white emulsion;

[0067] (4) Centrifuge the emulsion at a speed of 2000-3000r / min for 30 minutes to obtain a precipitate, and then place the precipitate at minus 70°C and a pressure of 0.01-0.005 Pa for 5-10 hours for freeze drying to obtain Encapsulated solid acid with a particle size of 20-45μm and a mass ratio of the capsule wall to the capsule core of 1:2.

Example Embodiment

[0068] Example 3: Preparation of fracturing acidification fluid.

[0069] The encapsulated solid acid prepared in Example 1 was used to prepare the fracturing acidification fluid according to the amount in Table 1.

[0070] Diversion experiment, core dissolution experiment and dynamic fluid loss determination were carried out on the prepared fracturing acidification fluid. The results are shown in Table 10.

[0071] Table 1 Composition of fracturing acidification fluid according to mass

[0072] Corresponding mineral acid hydrochloric acid15% Encapsulated solid acid Dry powder nitric acid particles3% Thickener Xanthan gum0.5% Iron ion stabilizer EDTA1.0% Corrosion inhibitor Pentadecyl imidazoline1.0% water margin

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Abstract

The present invention relates to an encapsulated solid acid, which comprises a capsule core and a capsule wall, wherein the material of the capsule core is nitric acid powder. According to the present invention, the encapsulated solid acid adopted as the additive of a fracturing acidizing liquid can effectively delay the acid release rate; the fracturing acidizing liquid prepared from the encapsulated solid acid can effectively solve the problems of short action time, low acid liquid corrosion efficiency, poor construction effect, difficult filtration loss control, short acid corrosion crack and the like caused by the too rapid acid liquid reaction during the acid fracturing process; and the encapsulated solid acid further has the efficient plugging relieving ability, the solid particles have the temporary plugging and filtration loss reducing functions, and the site construction is simple.

Description

technical field [0001] The invention belongs to the field of oil field chemical industry, and in particular relates to an encapsulated solid acid and its preparation and application. Background technique [0002] The world's oil and natural gas resources are declining and the demand is rising. Exploring new reserves and tapping the potential of old oil fields are the main measures to increase production. Among the newly discovered oil reservoirs, low-permeability reservoirs are gradually increasing; and after the old oil fields are developed to a certain stage, the oil layers need to be further improved to increase production. Among the stimulation measures, especially in carbonate reservoirs, acid fracturing technology is the most commonly used stimulation measure. [0003] Acid fracturing technology can be divided into common acid fracturing technology and deep acid fracturing technology near wellbore. The near-well acid fracturing technology can effectively remove the b...

Claims

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Application Information

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IPC IPC(8): C09K8/74C09K8/70
CPCC09K8/70C09K8/725C09K8/74
Inventor 张大年苏建政赵梦云苏长明张汝生张锁兵李颖刘松史爱萍唐萍郑承纲
Owner CHINA PETROLEUM & CHEM CORP
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