An organic acid system and preparation method for acidizing carbonate reservoir

A carbonate reservoir and organic acid technology, applied in the direction of chemical instruments and methods, drilling compositions, etc., can solve the problem that the effect of acidizing stimulation cannot reach the expected purpose, the length of acid-etched fractures cannot be increased, and oil and gas production is affected out of question

Active Publication Date: 2021-04-30
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, there are many deficiencies in the conventional hydrochloric acid working fluid. At present, the acid solution system for conventional fracturing acidification is usually 15% hydrochloric acid aqueous solution, but the reaction speed of hydrochloric acid and carbonate is too fast to increase the length of acid-etched fractures, resulting in the failure of fracturing operations. Gas production of post-construction wells is not high
In addition, the dissolution ability of conventional organic acid liquid is too weak, which may also cause severe pitting in the area around the wellbore, causing formation plugging and affecting oil and gas production
Therefore, the effect of acidification modification often fails to achieve the expected purpose

Method used

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  • An organic acid system and preparation method for acidizing carbonate reservoir
  • An organic acid system and preparation method for acidizing carbonate reservoir
  • An organic acid system and preparation method for acidizing carbonate reservoir

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] First set the quality of the organic acid system to be configured, prepare organic acid liquid, the mass fraction of organic acid liquid in the organic acid system is 45%, adopt formic acid, acetic acid, benzoic acid, oxalic acid, succinic acid and propionic acid to form a mixed organic acid The acid solution has a mass ratio of 3:2:1:0.5:2:1.5.

[0025] EDTA is disodium EDTA, with a mass fraction of 0.2%.

[0026] The other components are 1% of corrosion inhibitor, 0.03% of retarding additive, 0.03% of iron ion stabilizer and 0.1% of drainage aid.

[0027] The iron ion stabilizer uses citric acid solution with a mass fraction of 40%, the drainage aid uses CF-5B and 1831 to form a mixed solution with a mass ratio of 1:1, and the corrosion inhibitor consists of imidazoline corrosion inhibitors and quaternary ammonium salts. The corrosion agents are mixed according to the mass ratio of 0.5:1 to form a mixed corrosion inhibitor.

[0028] Hydrophobic modified nano-SiO was...

Embodiment 2

[0031] First, set the quality of the organic acid system to be configured, prepare an organic acid solution, the mass fraction of the organic acid solution is 50%, use formic acid, acetic acid, benzoic acid, oxalic acid, succinic acid and propionic acid to form a mixed organic acid solution, the mass ratio It is 3:2:1:0.5:2:1.5.

[0032] EDTA is selected from disodium EDTA, and the mass fraction is 0.5%.

[0033] The other components are 0.3% of corrosion inhibitor, 0.08% of retarding additive, 0.08% of iron ion stabilizer and 0.5% of drainage aid.

[0034] The iron ion stabilizer uses citric acid solution with a mass fraction of 40%, the drainage aid uses CF-5B and 1831 to form a mixed solution with a mass ratio of 5:1, and the corrosion inhibitor consists of organic phosphonate corrosion inhibitors and thiourea series The corrosion inhibitors are mixed according to the mass ratio of 2:1 to form a mixed corrosion inhibitor.

[0035] Hydrophobic modified nano-SiO was selecte...

Embodiment 3

[0038] First, the quality of the organic acid system to be configured is set, and the organic acid solution is prepared. The mass fraction of the organic acid solution is 55%. Formic acid, acetic acid, benzoic acid, oxalic acid, succinic acid and propionic acid are used to form a mixed organic acid solution. The mass ratio It is 3:2:1:0.5:2:1.5.

[0039] EDTA is selected from disodium EDTA, and the mass fraction is 0.7%.

[0040] The other components are 0.7% of corrosion inhibitor, 1% of retarding additive, 1% of iron ion stabilizer and 0.7% of drainage aid.

[0041] The iron ion stabilizer uses citric acid solution with a mass fraction of 40%, the drainage aid uses CF-5B and 1831 to form a mixed solution with a mass ratio of 2:1, and the corrosion inhibitor consists of imidazoline corrosion inhibitors and acetylenic alcohol inhibitors. The corrosion inhibitor is mixed according to the mass ratio of 1:1 to form a mixed corrosion inhibitor.

[0042] Hydrophobic modified nano...

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Abstract

The invention discloses an organic acid system and a preparation method for acidification reformation of carbonate rock reservoirs. The organic acid system includes organic acid liquid, corrosion inhibitor, EDTA, retarding additive, iron ion stabilizer, Discharge agent and water, wherein the mass fraction of each substance is 45%-60% for organic acid, 0.3%-2% for corrosion inhibitor, 0.2%-1% for EDTA, and 0.03%-1.5% for retarding additive, The iron ion stabilizer is 0.03%-1.5%, the drainage aid is 0.1%-1%, and the rest is water. The system can prevent corrosion under strong acid conditions through the use of corrosion inhibitors and other components, slow down the acidification of pipeline equipment, reduce the corrosion of equipment and pipe strings, reduce the acid-rock reaction rate, increase the length of acid-etched cracks, So as to achieve the effect of deep acidification transformation.

Description

technical field [0001] The invention belongs to the field of reservoir transformation of oil and gas fields, and relates to an organic acid system and a preparation method for acidification transformation of carbonate rock reservoirs. Background technique [0002] Carbonate reservoirs are currently the key areas of oil and gas exploration, and acidification is the main production increase measure for carbonate reservoir reconstruction. The purpose is to form wormholes in the formation through the reaction of organic acids and carbonate rock salts, and communicate natural gas seepage channels. To increase gas production, the conventional working fluid is mainly hydrochloric acid and hydrochloric acid compound system. [0003] However, there are many deficiencies in the conventional hydrochloric acid working fluid. At present, the acid solution system for conventional fracturing acidification is usually 15% hydrochloric acid aqueous solution, but the reaction speed of hydrochl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/74
CPCC09K8/74C09K2208/10C09K2208/32
Inventor 王历历李宪文丁里张燕明石华强李小玲刘晓瑞孟磊祖凯傅鹏
Owner PETROCHINA CO LTD
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