Preparation method of microbial polysaccharide modified copolymer gel plugging agent

A technology of microbial polysaccharide and gel plugging agent, applied in the field of oilfield chemistry, can solve the problems of poor temperature and salt resistance and erosion resistance, operator and formation damage, short production cycle, etc., and achieve salt resistance and shear resistance. Good, high sweep efficiency, improve the effect of mobility ratio

Inactive Publication Date: 2017-01-11
WUHAN INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, polyacrylamide is the most widely used blocking agent at home and abroad. Its molecular structure belongs to linear polymer compounds, and its temperature resistance, salt resistance and erosion resistance are poor. Using -CONH in its molecule 2 And -COOH can form a body-shaped structure polymer with a cross-linking agent, thereby increasing its strength. The chelating metal cross-linking system can withstand a temperature of 70-90 °C, and the organic phenolic cross-linking system can withstand a temperature of 70-120 °C, but The two cross-linking agents are highly polluting to the environment, and will cause varying degrees of harm to operators and formations
[0005] Microbial polysaccharides have a short production cycle and are not limited by seasons and regions. They are widely used due to their safety, non-toxicity, and unique physical and chemical properties. It is seldom used in profile control and is mostly suitable for medium and low temperature reservoirs

Method used

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  • Preparation method of microbial polysaccharide modified copolymer gel plugging agent
  • Preparation method of microbial polysaccharide modified copolymer gel plugging agent
  • Preparation method of microbial polysaccharide modified copolymer gel plugging agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The xanthan gum was prepared into a solution with a mass fraction of 0.1% with distilled water and stirred evenly, followed by adding 2.5 g of acrylamide (the mass ratio of xanthan gum to acrylamide was 1:10), 0.0825 g of N,N'-methylene bisacrylamide (accounting for 3% of the total mass of xanthan gum and acrylamide), nitrogen was introduced into the system, and Na 2 SO 3 0.0294g, (NH 4 ) 2 S 2 O 8 0.0532g (this initiation system accounts for 3% of the total mass of xanthan gum and acrylamide, wherein Na 2 SO 3 with (NH 4 ) 2 S 2 O 8 The molar ratio of 1:1), stirred evenly, and reacted in a constant temperature water bath at 50 °C for 8 h to form a gel.

[0033] The viscosity of the gel was measured by NDJ-8S viscometer 3.68×10 4 The effects of mPa·s, temperature and salinity on the gel strength of copolymers are as follows figure 2 and attached Figure 4 shown.

[0034] from figure 2 In the specific example 1, the influence curve of temperature on the ...

Embodiment 2

[0037]Xanthan gum is mixed with distilled water and is the solution that mass fraction is 0.3% and stirs evenly, adds the 2-acrylamido-2-methylpropanesulfonic acid of 5.0g successively (xanthan gum and 2-acrylamido-2- The mass ratio of methylpropanesulfonic acid is 1:20), 0.0525g of N,N'-methylenebisacrylamide (1% of the total mass of xanthan gum and 2-acrylamido-2-methylpropanesulfonic acid %), feed nitrogen into the system, add Na in turn 2 SO 3 0.0373g, (NH 4 ) 2 S 2 O 8 0.0676g (this initiating system accounts for 2% of the total mass of xanthan gum and 2-acrylamido-2-methylpropanesulfonic acid, wherein Na 2 SO 3 with (NH 4 ) 2 S 2 O 8 The molar ratio is 1:1), stirred evenly and reacted in a constant temperature water bath at 50°C for 8 hours to form a gel.

[0038] Measure the viscosity of the gel with NDJ-8S viscometer 4.26×10 4 mPa·s, the effect of temperature and salinity on the gel strength of the copolymer is shown in the attached figure 2 and attached ...

Embodiment 3

[0042] Chitosan was formulated with distilled water into a solution with a mass fraction of 1% and stirred evenly, followed by adding 15g of acrylamide (the mass ratio of chitosan to acrylamide was 1:15), 0.8g of N,N'-methylene base bisacrylamide (accounting for 5% of the total mass of chitosan and acrylamide), feed nitrogen into the system, add initiator (NH 4 ) 2 [Ce(NO 3 ) 6 ] 0.64g (the initiation system accounts for 4% of the total mass of chitosan and acrylamide), stirred evenly and reacted in a constant temperature water bath at 50°C for 8h to form a gel.

[0043] Measure the viscosity of the gel with NDJ-8S viscometer 8.64×10 4 mPa·s, the effect of temperature and salinity on the gel strength of the copolymer is shown in the attached figure 2 and attached Figure 4 shown.

[0044] from figure 2 In specific example 3, the influence curve of temperature on the copolymer gel strength can be seen that as the ambient temperature increases, the gel viscosity increas...

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Abstract

The invention relates to a method for preparing a microbial polysaccharide modified copolymer gel plugging agent. The method comprises the following steps: adding an amide monomer into a microbial polysaccharide solution, further adding a cross-linking agent, introducing nitrogen for isolating air into a sealed system, adding an initiator, and reacting for 4-24 hours at the constant temperature of 30-60 DEG C, thereby preparing the gel plugging agent. The method has the advantages that firstly, the gelling time and the gel strength are controllable; secondly, injection risk is prevented, pipelines and shafts are not plugged, the plugging agent has pseudoplastic property, and after the gel is filled into an underground layer, the original strength can be still recovered after a pump is stopped and the shaft is closed; thirdly, large-scale treatment can be performed, the gel can be filled into a deep part of a stratum and is not greatly retained near the shaft bottom to limit the entering depth; fourthly, relatively high strength is achieved, high temperature oil deposit of 70-130 DEG C is adapted, and technical guarantee is provided for exploration of the high temperature oil deposit; and fifthly, the mineralization degree is 25*10<4>mg / L, so that the gel is relatively high in strength and is applicable to high-salt oil deposit.

Description

technical field [0001] The invention belongs to the technical field of oil field chemistry, and relates to a preparation method of a microbial polysaccharide modified copolymer gel plugging agent. [0002] technical background [0003] Due to the complex formation structure, formation heterogeneity, and differences in crude oil physical properties, injection into the exploitation oil field, the three contradictions within the formation, between layers and plane are prominent, resulting in the production of oil wells, and the water production of oil wells consumes more formation energy, and at least makes oil well production. The decrease in oil volume will lead to an increase in the pressure of the liquid column in the wellbore, which will make the oil well lose its production value. In addition, the water output of the oil well will harm the oil production equipment, increase the corrosion rate of the equipment, and increase the dehydration treatment of crude oil, thereby inc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F251/00C09K8/42
Inventor 杨隽闫霜王芬徐黎刚姚棋谢浩杨晓梅
Owner WUHAN INSTITUTE OF TECHNOLOGY
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