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Preparation method of polymer weak gel deep profile control agent

A deep profile control and weak gel technology, which is applied in the direction of drilling compositions, chemical instruments and methods, can solve the problems of narrow range of temperature and salt resistance, short gelation time, high cost, etc., to reduce production costs, The ratio of solid content is low and the gelling performance is good

Inactive Publication Date: 2013-10-02
WUHAN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Bulk gel deep profile control technology has high cost, short gelation time, difficult liquid preparation and construction, requires special liquid preparation and aging equipment, and is not suitable for deep reservoir profile control; colloidal dispersion gel is not suitable for fractures and large pores For oil reservoirs, the service limit temperature is 94°C, and it is prepared with clean water. The formation adaptability is poor, and the evaluation is difficult. Factors such as shear, adsorption, salinity, and long-term migration will affect the strength of the colloidal dispersion gel; The preparation process of pre-crosslinked gel particles is complicated, the cost is high, and the scope of application is narrow
[0004] Weak gel deep profile control technology combines the advantages of polymers to improve mobility ratio and control and flooding to improve reservoir heterogeneity, and can well solve the problems of interlayer flow and intralayer flow in reservoirs. The treatment of water injection wells in most oilfields has been successfully implemented. However, there are still great limitations in the field application of weak gels in oilfields. One of them is that the temperature range of weak gels is narrow (30-90°C). At 30°C, the gelation speed is too slow or even no gelation at all. When the temperature is higher than 90°C, the gelation speed is too fast and difficult to control, and the stability after gelation is poor
[0005] At present, many oil fields use phenolic resin weak gel, and use a highly toxic phenolic crosslinking agent, but this chemical reagent is highly volatile, has a serious impact on the environment and operators, and has low reaction ability and large dosage
The research on the modification of sodium carboxymethyl cellulose grafting other monomers found that the resulting polymer has shorter branched chains and a smaller molecular weight. The research on sodium carboxymethyl cellulose grafting acrylamide, although the molecular weight of the obtained polymer has Significantly improved, but the polymer is a linear polymer with a narrow range of temperature and salt resistance, which is limited in the application of oil reservoirs

Method used

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  • Preparation method of polymer weak gel deep profile control agent
  • Preparation method of polymer weak gel deep profile control agent
  • Preparation method of polymer weak gel deep profile control agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 1% solution with distilled water and stir evenly, then add 10.00 g of acrylamide and 0.0075 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0566g, (NH 4 ) 2 S 2 o 8 0.1065g, stir well and react in a constant temperature water bath at 40°C for 8 hours to form a gel.

[0033] Precipitate and separate the prepared polymer weak gel with ethanol solvent, dry to obtain a crude cross-linked polymer, extract the crude cross-linked polymer with acetone in a Soxhlet extractor for 10 hours to remove the homopolymer, and dry it in a vacuum to obtain Pure cross-linked polymer. Take the dried raw material of sodium carboxymethyl cellulose and purified polymer weak gel 2~3mg and 200~300mg of dry KBr powder and mix them in an agate mortar, fully grind until the particle diameter is less than 2μm, and use stainless steel Scoop 70-90mg into...

Embodiment 2

[0039] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 1% solution with distilled water and stir evenly, then add 10.00 g of acrylamide and 0.0063 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0666g, (NH 4 ) 2 S 2 o 8 0.1209g, stirred evenly and reacted in a constant temperature water bath at 30°C for 8 hours to form a gel.

[0040] The viscosity of the gel measured by NDJ-8S viscometer is 10520mPa·s, and the temperature and salt resistance properties are shown in the attached image 3 And attached Figure 5 shown.

Embodiment 3

[0042] Prepare 2.50 g of sodium carboxymethylcellulose (CMC) with a viscosity of 800-1200 mPa·s into a 2% solution with distilled water and stir evenly, then add 12.50 g of acrylamide and 0.0075 g of N,N'-methylene Base bisacrylamide, pass nitrogen into the system, add Na in turn 2 SO 3 0.0694g, (NH 4 ) 2 S 2 o 8 0.1255g, stir well and react in a constant temperature water bath at 40°C for 8 hours to form a gel.

[0043] The viscosity of the gel measured by NDJ-8S viscometer is 13280mPa·s, and the temperature and salt resistance properties are as follows: image 3 And attached Figure 5 shown.

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Abstract

The invention relates to a preparation method of a polymer weak gel deep profile control agent. The preparation method comprises the following steps of preparing sodium carboxymethyl cellulose and distilled water into sodium carboxymethyl cellulose water solution of which the mass percentage is 1%-2%; adding acrylamide of which the mass is 2-8 times as great as that of the sodium carboxymethyl cellulose into the sodium carboxymethyl cellulose water solution, and then adding a cross-linking agent which accounts for 0.01%-2% of the total weight of the sodium carboxymethyl cellulose and the acrylamide; enabling nitrogen to enter into a closed system and isolating the air, and adding an initiating agent which accounts for 1%-2% of the total mass of the sodium carboxymethyl cellulose and the acrylamide; and discharging after carrying out constant-temperature reaction for 4-12 hours under the temperature of 30-60 DEG C. According to the preparation method disclosed by the invention, the acrylamide is grafted to the sodium carboxymethyl cellulose, polymer weal gel with a mesh structure is formed under the action of the initiating agent and the cross-linking agent, and a polymer weak gel system integrates the advantages of the sodium carboxymethyl cellulose and the acrylamide.

Description

technical field [0001] The invention belongs to the technical field of oilfield chemistry and relates to a preparation method of a polymer weak gel deep profile control agent. technical background [0002] At present, most oilfields on land in China are already in the period of high water-cut or ultra-high water-cut exploitation, and the pore structure of most oil layers has undergone great changes after long-term water injection or water flooding, and the heterogeneity has become more serious, and high-permeability channels have gradually formed in the oil layers Or large pores make the formation pressure field and streamline field form a fixed potential, forming a dominant water flow channel between oil and water wells, resulting in a "short circuit" of water flooding, and the injected water rushes into the oil well along the high permeability zone, resulting in an increase in the water content of the oil well. decline. For conventional cross-linked polymer profile contro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/44C09K8/588C08F251/02C08F220/56C08F222/38
Inventor 杨隽闫霜高玉军徐黎刚谢浩杨晓梅姚棋
Owner WUHAN INSTITUTE OF TECHNOLOGY
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