A kind that can absorb co 2 Acidification retarder for forming isolation layer, preparation method and application

A retarder and isolation layer technology, which is applied in the field of acidification retarder and preparation, can solve the problems of high acid fracturing construction pressure, low displacement, and reduced foam acid stability, and achieve the effect of reducing the degree of acid rock reaction

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

AI Technical Summary

Problems solved by technology

Emulsifying acid is to make acid and oil in the presence of an emulsifier to form an acid-in-oil emulsion. When stable, the oil separates the acid liquid from the surface of the formation, so that the acid liquid can enter the deep part of the reservoir and deeply stimulate the reservoir , which has the advantages of small filtration loss, good retarding performance, and can penetrate deep into the formation; the disadvantage is that the construction friction is relatively high, which is higher than that of ordinary acid, resulting in high acid fracturing pressure and low displacement
Foam acid is composed of acid liquid, gas, foaming agent, foam stabilizer, functional surfactant, etc. The system replaces conventional acid liquid with aerated or gasified acid liquid to reduce the acid-rock reaction rate and realize deep Penetration, but under high temperature conditions, the stability of foam acid decreases rapidly, thus affecting the effect of retarded acidification

Method used

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  • A kind that can absorb co <sub>2</sub> Acidification retarder for forming isolation layer, preparation method and application
  • A kind that can absorb co <sub>2</sub> Acidification retarder for forming isolation layer, preparation method and application
  • A kind that can absorb co <sub>2</sub> Acidification retarder for forming isolation layer, preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] One that can absorb CO 2 An acidification retarder forming an isolation layer, the acidification retarder is composed of a monomer solution and an initiator,

[0029] The material ratio of the monomer solution is: 4.0-6.0 wt% of acrylamide, 8.0-10.0 wt% of 2-acrylamide-2-methylpropanesulfonic acid, perfluoroalkyl amidopropyl dimethyl allyl chloride 0.1-1.0 wt% ammonium chloride, 1.0-10.0 wt% ammonium sulfate, 5-25 wt% sodium hydroxide solution with a concentration of 10% by mass, and the balance is water;

[0030] The initiator is composed of 1.0% potassium persulfate by mass percentage concentration and 1.0% 2,3,5,6-tetrahydroxy-2-hexenoic acid-4-lactone by mass percentage concentration. The dosage of body solution is 2.0-6.0wt% and 1.0-4.0wt% respectively.

[0031] The described one can absorb CO 2 Form the preparation method of the acidification retarder of isolation layer, this preparation method comprises the following steps:

[0032] Step 1: acrylamide, 2-acry...

Embodiment 2

[0041] On the basis of Example 1, the described one can absorb CO 2 The molecular structural formula of the acidification retarder forming the isolation layer is as follows:

[0042]

[0043] Wherein, X, Y, and Z are respectively the number of moles of the corresponding units, and the ratio of the number of moles of X, Y, and Z is:

[0044] X:Y:Z=(6-10):(4-6):(0.01-0.3).

Embodiment 3

[0047] Add acrylamide 5wt%, 2-acrylamide-2-methylpropanesulfonic acid 10.0wt%, perfluoroalkyl amidopropyl dimethyl allyl ammonium chloride 0.1wt%, ammonium sulfate 4.90wt% in a 2000mL three-necked flask wt% and 40.0wt% water, start stirring until completely dissolved, add 10% sodium hydroxide to dissolve 20.0wt%, adjust pH=6.35, add 20.0wt% water to obtain a monomer solution;

[0048]At a temperature of 25°C, pass nitrogen to the monomer solution for 30 minutes to remove oxygen, then add 1.0% potassium persulfate aqueous solution of 4.0 wt%, continue to pass nitrogen for 5 minutes, and add 1.0% by mass concentration 2,3,5,6 -Tetrahydroxy-2-hexenoic acid-4-lactone aqueous solution 2.0wt%. When the reaction starts, the temperature rises and the viscosity increases. When the temperature is higher than 45°C, heat the reaction at 50°C in a water bath for 8 hours to obtain a colorless transparent acidified slow Accelerator.

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Abstract

The invention relates to the field of deep acid fracturing in oil and gas wells, in particular to a 2 The acidification retarder that forms the isolation layer and its preparation method and application, on the basis of overcoming the high viscosity of the existing acid liquid system, large construction friction and combining the requirements of rapid liquid preparation and construction on site, a kind of acid that can absorb CO is prepared by polymerization reaction 2 The acid retarder that forms the isolation layer, the ionized sulfonic acid in the acid system can adsorb the rock surface, reducing the acid-rock reaction rate, and the fluorocarbon chain in the molecule can adsorb CO 2 An effective isolation layer is formed on the surface, which effectively reduces the diffusion of H+ and achieves the effect of deep acidification.

Description

[0001] Technical field [0002] The invention relates to the field of deep acid fracturing in oil and gas wells, in particular to a 2 An acidification retarder for forming an isolation layer, a preparation method and application thereof. Background technique [0003] Increasing the effective penetration distance of acid fracturing is one of the important ways to improve the output of acid fracturing. An excellent acid solution system should first have the ability to control the diffusion of H+ in the liquid phase to the rock surface, so as to reduce the reaction rate of acid rock, realize uniform acid distribution, and slow acidification, so as to increase the acidification penetration distance and achieve the purpose of deep acidification. [0004] Currently widely used thickening acid and gel acid limit the convection between acid liquid and rock by increasing the viscosity of acid liquid, and the transfer of hydrogen ions is limited to diffusion, thus effectively delaying ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F220/58C08F220/56C08F226/02C09K8/74
CPCC08F220/56C08F220/58C09K8/725C09K8/74
Inventor 石华强李宪文丁里张燕明刘晓瑞李小玲孟磊王历历祖凯傅鹏
Owner PETROCHINA CO LTD
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