A gel acid system and its preparation for acid fracturing in carbonatite reservoirs

A carbonatite storage and jelly acid technology, which is applied to drilling compositions, chemical instruments and methods, etc., can solve the problems of inability to effectively reduce the filtration loss of formation conditions, fast reaction speed of acid rock, and limited acid viscosity.

Active Publication Date: 2016-05-11
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] 1) Under the temperature conditions of deep wells and ultra-deep wells, the reaction speed of acid rock is fast, which is not conducive to the deep penetration of acid liquid;
[0013] 2) The viscosity of the acid solution is limited, which is not enough to effectively reduce the fluid loss of the acid solution
In particular, the acid liquid has poor high-temperature shear resistance, and the retention time of the high-viscosity process is short, which cannot effectively reduce the filtration loss under formation conditions.

Method used

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  • A gel acid system and its preparation for acid fracturing in carbonatite reservoirs
  • A gel acid system and its preparation for acid fracturing in carbonatite reservoirs
  • A gel acid system and its preparation for acid fracturing in carbonatite reservoirs

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Effect test

Embodiment 1

[0030] amino acid preparation

[0031] ①Under high-speed stirring, slowly and evenly add the powdered CYY-160 gelling agent into the acid solution. Since the gelling agent is a high-molecular polymer, pay attention to avoid forming lumps (fish eyes), and stir for 2 hours (200ml is a batch);

[0032] ②Let the acid stand for at least 16-24 hours for hydration;

[0033] ③ Add 1% CYY-1 cross-linking agent or first add 1% cross-linking retarder CYY-3 and then add 1% CYY-1 cross-linking agent.

Embodiment 2

[0035] Preparation of finished acid: 20% HCl + 0.8% CYY-160 + 1% CYY-1 cross-linking agent + 1% CYY-3 cross-linking retarder.

[0036] The 6300 reciprocating capillary viscometer of Chandler Company was used to measure the rheological properties of finished acid. The detection principle is: normal temperature -90 ℃ shear rate 40s -1 ;90℃-140℃ shear rate 170s -1 .

[0037] 90℃-140℃, shear rate is 170s -1 test results:

[0038] Table 2-2-9 Viscosity temperature data of formula 190℃-140℃

[0039]

Embodiment 3

[0041] Preparation of finished acid: 20% HCl + 0.8% CYY-160 + 1% CYY-1 cross-linking agent + 1% CYY-3 cross-linking retarder.

[0042] The reaction rates of common hydrochloric acid and jelly acid were measured with a rotary rock instrument.

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Abstract

The invention relates to a colloid acid system for the acid fracturing of a carbonate reservoir and a preparation method thereof. The colloid acid system is characterized by being prepared by adding 0.8% of CYY-160, 1% of CYY-1 cross-linking agent and 1% of CYY-3 cross-linking retarder in HCl with the mass concentration of 20% in terms of the weight of HCl with the mass concentration of 20% as 100%, wherein the CYY-160 is a copolymer of 2-sulfoacrylamide-methylpropanesulfonic acid and N,N-dimethacrylamide; the CYY-1 is a compound of zirconium acetate, zirconium lactate and zirconium oxide; the CYY-3 is one of citric acid and lactic acid; and under a condition of 90 DEG C, the viscosity of a basic acid of the colloid acid system is more than 1000 mPa.s, the retardant rate is more than 85%, and the viscosity of gel breaking liquid is less than 15 mPa.s.

Description

technical field [0001] The invention relates to an acid liquid system applied to acid fracturing reformation of carbonatite reservoirs and its preparation. Background technique [0002] The deep acid fracturing technologies used in deep acid fracturing of carbonate reservoirs can be summarized into the following technical series. [0003] 1) Gelled acid (thickened acid) acid fracturing technology [0004] The optimal viscosity of thickening acid in the ground is generally around 25mPa.S-30mPa.S, and the flowback viscosity of residual acid is generally between 5mPa.S-14mPa.S, which is easy to flow back and can carry the residual acid in formation fractures after reaction. solid particles. [0005] 2) Slow acid process technology [0006] Chemical retarded acid is a conventional acid added with surfactant. This system has a large fluid loss and is mainly suitable for medium and low temperature dolomite reservoirs. Due to the poor control of fluid loss, this technology is c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/74
Inventor 袁飞王斌成一张健强
Owner PETROCHINA CO LTD
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