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Completion fluid pH value buffer agent and preparation method thereof

A technology of completion fluid and buffer, applied in chemical instruments and methods, drilling composition, etc., can solve problems such as high cost and strong corrosion, achieve high efficiency, prevent casing damage and cracks, and prevent metal from further The effect of corrosion

Inactive Publication Date: 2019-01-04
CNPC BOHAI DRILLING ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a pH buffering agent for completion fluid that solves the problems of high cost and strong corrosion caused by the current single ammonia-ammonium chloride buffer system

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A pH buffering agent for well completion fluid, the preparation steps of which are as follows:

[0019] S1. Prepare 0.1mol / L NH 4 Cl solution and 0.1mol / L NH 3 .H 2 O, then weigh 70 parts by weight of NH 4 Cl solution and 30 parts by weight of ammonia water, and the two are stirred and mixed uniformly to obtain the first buffer solution system with a pH of 9.25;

[0020] S2, prepare 0.1mol / L Na 2 CO 3 solution with 0.1mol / L NaHCO 3 solution, then weigh 60 parts by weight of Na 2 CO 3 solution and 40 parts by weight of NaHCO 3 solution, and the two are stirred and mixed uniformly to obtain a second buffer system with a pH of 10.15;

[0021] S3. Weigh the first buffer solution system and the second buffer solution system according to the weight ratio of 8:2, and mix them evenly to obtain the pH buffer I for well completion fluid.

Embodiment 2

[0023] A pH buffering agent for well completion fluid, the preparation steps of which are as follows:

[0024] S1. Prepare 0.1mol / L NH 4 Cl solution and 0.1mol / L NH 3 .H 2 O, then weigh 50 parts by weight of NH 4 Cl solution and 50 parts by weight of ammonia water, and the two are stirred and mixed uniformly to obtain a first buffer system with a pH of 10.15;

[0025] S2, prepare 0.1mol / L Na 2 CO 3 solution with 0.1mol / L NaHCO 3 solution, then weigh 50 parts by weight of Na 2 CO 3 solution and 50 parts by weight of NaHCO 3 solution, and the two are stirred and mixed uniformly to obtain a second buffer system with a pH of 9.65;

[0026] S3. Weigh the first buffer solution system and the second buffer solution system according to the weight ratio of 7:3, and mix them evenly to obtain the pH buffer agent II for well completion fluid.

Embodiment 3

[0028] A pH buffering agent for well completion fluid, the preparation steps of which are as follows:

[0029] S1. Prepare 0.1mol / L NH 4 Cl solution and 0.1mol / L NH 3 .H 2 O, then weigh 60 parts by weight of NH 4 Cl solution and 40 parts by weight of ammonia water, and the two are stirred and mixed uniformly to obtain the first buffer solution system with a pH of 9.65;

[0030] S2, prepare 0.1mol / L Na 2 CO 3 solution with 0.1mol / L NaHCO 3 solution, then weigh 70 parts by weight of Na 2 CO 3 solution and 30 parts by weight of NaHCO 3 solution, and the two are stirred and mixed uniformly to obtain a second buffer system with a pH of 10.85;

[0031] S3. Weigh the first buffer solution system and the second buffer solution system according to the weight ratio of 9:1, and mix them evenly to obtain the pH buffer agent III for well completion fluid.

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PUM

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Abstract

The invention discloses a completion fluid pH value buffer agent which is a mixed liquid of a first buffer liquid system and a second buffer liquid system, wherein the pH value of the mixed liquid is9.85-10.45; the first buffer liquid system is a mixed solution of an ammonium chloride solution and ammonia water; the pH value of the first buffer liquid system is 9.15-10.35; the second buffer liquid system is a mixed solution of sodium carbonate and sodium bicarbonate; the pH value of the second buffer liquid system is 9.0-10.5. The completion fluid pH value buffer agent is high in efficiency in removing hydrogen sulfide and the like and inhibiting iron scale and is capable of effectively preventing sleeve damage and cracks caused by hydrogen brittleness and hydrogen induced brittleness; inaddition, due to addition of the completion fluid pH value buffer agent, a completion fluid is constantly maintained under an alkali condition, corrosion products, namely ferric hydroxide and iron carbonate, have very low solubility, a metallic surface is solidly covered by a small amount of generated ferric hydroxide and iron carbonate, further corrosion of a metal can be prevented, and a stablecompletion fluid system can be maintained.

Description

technical field [0001] The invention relates to the technical field of well completion fluid, in particular to a pH buffer for well completion fluid and a preparation method thereof. Background technique [0002] At present, the commonly used brine completion fluid system has CaCl 2 system, CaBr 2 system, CaCl 2 / invent CaBr 2 system, formate system, etc. CaCl 2 The system is widely adapted to the density of 1.4g / cm 3 For the following completion fluid systems, the pH value of the system is neutral; CaCl 2 / invent CaBr 2 The system is widely adapted to the density of 1.8g / cm 3 The completion fluid system below is low in corrosion, and the pH value of the system is approximately neutral; while the formate system belongs to the completion fluid system for reservoir protection and is suitable for a density of 1.55g / cm 3 Below, low corrosion, the pH value of the system is weakly alkaline. When the completion fluid of the above system is used in a sour gas field, due to...

Claims

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Application Information

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IPC IPC(8): C09K8/03
CPCC09K8/032
Inventor 刘音王晓磊马吉龙王颖解同川李博曹宁王丹唐智博杨津王瑞泓
Owner CNPC BOHAI DRILLING ENG
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