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Microemulsion for eliminating water blocking damage of low-permeability reservoirs

A microemulsion and oil seepage technology, applied in drilling compositions, chemical instruments and methods, etc., can solve the problems of water lock pollution, low production of oil wells, affecting the economic development of oilfields, etc. , Prevent and remove the effect of water lock damage

Active Publication Date: 2018-09-25
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Once external water invades the oil well under a certain pressure during the production operation, causing water lock pollution in the near well area, it is difficult to recover through natural energy, resulting in low production and low liquid of the oil well, which seriously affects the economic development of the oil field
The current release system is mainly aimed at medium-high permeability reservoirs, and the release effect is not ideal for low-permeability reservoirs. Therefore, it is urgent to develop a water lock damage release system suitable for low-permeability reservoirs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Example 1 Preparation of a microemulsion for removing water lock damage in low permeability reservoirs

[0018] The components and dosage are as follows: 10g non-ionic surfactant nonylphenol polyoxyethylene ether, 10g sodium dodecylbenzene sulfonate, 8g alkyl dimethyl betaine (alkyl refers to alkane with 12 carbon atoms Base), 6g ethanol, 8g light diesel, 58g water.

[0019] The preparation method is as follows: at room temperature, add the auxiliary agent to water, stir evenly, stirring speed 20r / min; then, add non-ionic surfactant, stir evenly, stirring speed 5r / min; add anionic surfactant, stir evenly, Stirring speed 5r / min; add stabilizer, stir evenly, stirring speed 5r / min; finally add diesel oil, stir evenly, stirring speed 30r / min, that is, uniform transparent agent, after testing, its performance parameters are as follows: at 20 ℃ , The solubility of colloid is 21mg / L, the recovery rate of oil phase permeability of low permeability reservoirs after water invasion is...

Embodiment 2

[0020] Example 2 Preparation of a microemulsion for removing water lock damage in low permeability reservoirs

[0021] The components and dosage are as follows: 15g non-ionic surfactant nonylphenol polyoxyethylene ether, 12g sodium dodecylbenzene sulfonate, 10g alkyl dimethyl betaine (alkyl refers to alkane with 12 carbon atoms) Base, namely: dodecyl dimethyl betaine), 8g ethanol, 8g light diesel, 47g water.

[0022] The preparation method is: mixing and stirring at room temperature to obtain a uniform transparent agent, which is a microemulsion. After testing, its performance parameters are as follows: at 20℃, the solubility of colloid is 28mg / L, and it is resistant to low permeability reservoirs after water invasion. The oil phase permeability recovery rate is ≥92%, and the salinity resistance is 25000mg / L.

Embodiment 3

[0023] Example 3 Preparation of a microemulsion for removing water lock damage in low permeability reservoirs

[0024] The component composition and dosage are as follows: 20g non-ionic surfactant nonylphenol polyoxyethylene ether, 15g sodium dodecylbenzene sulfonate, 15g alkyl dimethyl betaine (alkyl refers to alkane with 12 carbon atoms Base), 10g ethanol, 8g light diesel, 32g water.

[0025] The preparation method is: mixing and stirring at room temperature to obtain a uniform transparent agent, which is a microemulsion. After testing, its performance parameters are as follows: at 20℃, the solubility of colloid is 31mg / L, and it is resistant to low permeability reservoirs after water invasion The oil phase permeability recovery rate is ≥95%, and the salinity resistance is 20000mg / L.

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Abstract

The invention discloses a microemulsion for eliminating water blocking damage of low-permeability reservoirs. The microemulsion comprises, by weight, 10% to 20% of a nonionic surfactant, 10% to 15% ofan anionic surfactant, 8% to 15% of a stabilizer, 6% to 10% of an auxiliary, 8% of diesel oil and 32% to 58% of water. The microemulsion for eliminating water blocking damage of low-permeability reservoirs has high oil-water intermiscibility, is free of oil-water two-phase interfacial tension, can effectively treat water invasion damage at near-wellbore zones of low-permeability reservoirs, and allows oil-phase permeability recovery to be no less than 90%. The microemulsion has high salt tolerance, being 20,000 mg / L or above. Besides the ability of eliminating water blocking damage, the microemulsion can also dissolve colloidal asphaltenes precipitated in the near-wellbore zone, with a dissolution rate being 20 mg / L or more. The microemulsion of the invention can effectively prevent and eliminate water locking damage and protect oil and gas layers to the greatest extent.

Description

Technical field [0001] The invention relates to a microemulsion used for removing water lock damage in low-permeability oil reservoirs, and belongs to the field of low-permeability oil reservoir mining operations. Background technique [0002] With the large-scale development of petroleum, the water content of medium and high permeability reservoirs has gradually increased, and the comprehensive water content of domestic high permeability reservoirs is above 92%, and the focus of oil development has shifted to low permeability reservoirs. Due to the small pore throat diameter of low-permeability oil reservoirs, the capillary force of the reservoir is stronger, which is different in magnitude compared with medium-high permeability oil reservoirs. In the course of mining operations, once external water intrudes into the oil well under a certain pressure and causes water lock pollution in the near-well area, it is difficult to recover through natural energy, resulting in low oil pro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/584C09K8/60C09K8/524
CPCC09K8/524C09K8/584C09K8/602
Inventor 汪庐山刘希明李建兵党娟华张金秋宋志东张君杨景辉李强宋欣
Owner CHINA PETROLEUM & CHEM CORP