A linear gel fracturing fluid for automatic gel breaking in reservoirs and its preparation method

An automatic gel breaking and linear gel technology, applied in chemical instruments and methods, drilling compositions, etc., can solve the problems of difficult gel breaking, high residue content of guar gum, large reservoir damage, etc. Viscoelasticity and sand-carrying properties, simple preparation effect

Inactive Publication Date: 2020-09-29
SOUTHWEST PETROLEUM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, most of the commonly used linear fracturing fluids are formulated with guar gum, which has a high content of guar gum residue, making it difficult to completely break the gel and cause great damage to the reservoir

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Preparation of linear gel fracturing fluid for automatic gel breaking in reservoirs

[0023] (1) Dissolve 0.1 mole of maleic anhydride in 10 mL of ethanol, slowly add dropwise the ethanol solution of 0.1 mole of dodecylamine, react at room temperature for 4 h, filter to obtain maleic acid monododecamide; the mole fraction is 99.5% Acrylamide and 0.5% maleic acid monododecylamide are dissolved in water to prepare a solution with a monomer concentration of 20%, adjust the pH, pass nitrogen gas for 30 minutes, heat up to 45°C, add an initiator, and react 8h, the anionic hydrophobic association polymer is obtained, and the critical association concentration is 3500mg.L -1 ;

[0024] (2) Disperse 5 g of oleic acid amidopropyl dimethylamine in 95 mL of deionized water, and then pass CO 2 To saturation, a clear and transparent heat-labile surfactant solution is obtained; (3) configure 3000mg.L -1 The associative polymer solution, then add 300mg.L -1 The thermally unsta...

Embodiment 2

[0028] (1) Preparation of linear gel fracturing fluid for automatic gel breaking in reservoirs

[0029] (1) Dissolve 0.1 mole of maleic anhydride in 10 mL of ethanol, slowly add dropwise the ethanol solution of 0.1 mole of dodecylamine, react at room temperature for 4 h, filter to obtain maleic acid monododecamide; the mole fraction is 99.3% Acrylamide and maleic acid monododecylamide with a mole fraction of 0.7% are dissolved in water to prepare a solution with a monomer concentration of 15%, adjust the pH, pass nitrogen gas for 30 minutes, heat up to 45°C, add an initiator, and react 8h, the anionic hydrophobic association polymer is obtained, and the critical association concentration is 3000mg.L -1 ;

[0030] (2) Disperse 5 g of erucamidopropyl dimethylamine in 95 mL of deionized water, and then pass CO 2 To saturation, a clear and transparent heat-labile surfactant solution is obtained; (3) configure 2500mg.L -1 The associative polymer solution, then add 400mg.L -1 Th...

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Abstract

The invention discloses a linear gel fracturing fluid for automatically breaking a reservoir in shale gas fracturing and a preparation method thereof. The linear gel fracturing fluid is formed through self-assembly of an anionic hydrophobic associated polymer and a thermally-unstable cationic surfactant. According to the technical scheme, the method comprises the following steps: (1) copolymerizing dodecylmaleimide serving as a hydrophobic monomer and acrylamide to obtain the anionic hydrophobic associated polymer; (2) reacting long-carbon-chain tertiary amine with CO2 to prepare a thermally-unstable ammonium bicarbonate cationic surfactant; (3) adding a thermally-unstable surfactant of 100 to 600mg.L<-1> with a hydrophobic associated polymer solution slightly lower than a critical association concentration to form the linear gel fracturing fluid for automatically breaking the reservoir. The linear gel fracturing fluid for automatically breaking the reservoir has high proppant carrying capacity in the ground and a shaft; the thermally-unstable surfactant is decomposed in the reservoir, and the linear gel fracturing fluid plays a role in automatic breaking, so that damage to the reservoir is reduced; the linear gel fracturing fluid has a wide application prospect in shale gas fracturing.

Description

technical field [0001] The invention relates to a linear glue fracturing fluid for automatically breaking glue in reservoirs for shale gas fracturing and a preparation method thereof. Background technique [0002] Due to the characteristics of low porosity and low permeability of shale gas reservoirs, exploration and development are difficult, and most shale gas wells need reservoir reconstruction to obtain ideal production. At present, foreign countries mainly use mixed fracturing fluids formed by slick water, linear gel and jelly fracturing fluids for volume fracturing. However, most of the commonly used linear gel fracturing fluids are formulated with guar gum, which has a high content of guar gum residues, making it difficult to completely break the gel and cause great damage to the reservoir. [0003] Therefore, the present invention provides a linear gel fracturing fluid for automatic gel breaking of reservoirs and a preparation method thereof. The linear glue fractu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/68
CPCC09K8/602C09K8/68C09K8/882
Inventor 郑存川黄志宇鲁红升全红平
Owner SOUTHWEST PETROLEUM UNIV
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