Medium-low temperature gel based on cationic cross-linking agent and used for stratum plugging

A cationic, low-temperature gel technology, applied in the direction of drilling compositions, chemical instruments and methods, etc., can solve the problems of unfavorable time control, poor resistance to mineralization, prolonged gelation time, etc., to achieve easy Good operation, good salt resistance, good gelling effect

Active Publication Date: 2020-07-03
YANGTZE UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although low-toxicity polyethyleneimine (PEI) is widely used to cross-link HPAM under low temperature conditions, the gel system has poor resistance to mineralization, and when the gel solution is mixed with formation water, the gelation time is greatly prolonged , which is not conducive to the control of on-site operation time

Method used

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  • Medium-low temperature gel based on cationic cross-linking agent and used for stratum plugging
  • Medium-low temperature gel based on cationic cross-linking agent and used for stratum plugging
  • Medium-low temperature gel based on cationic cross-linking agent and used for stratum plugging

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Experimental program
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Effect test

Embodiment 1

[0026] In this embodiment, the preparation method of the medium and low temperature gel for formation plugging comprises the following steps:

[0027] Step 1. Synthesis of cationic crosslinking agent-poly(4-vinylbenzenetetrahydrothiophene tetrafluoroborate)

[0028] S1: Add 0.25mol 4-vinylbenzyl chloride and 0.24mol tetrahydrothiophene to methanol, keep stirring in a dark environment for 4 days, remove methanol by vacuum distillation, wash with a large amount of acetone for 3 times and dry , to obtain a light yellow powdery solid, dissolve the solid in 40g of water, add 0.50mol sodium tetrafluoroborate, stir at room temperature for 1 hour, then filter to obtain a precipitate, wash the precipitate with a small amount of cold water and 250mL ether, and dry to obtain White powdery solid particles, that is, 4-vinylbenzenetetrahydrothiophene tetrafluoroborate;

[0029] S2: Weigh 0.20mol of 4-vinylbenzenetetrahydrothiophene tetrafluoroborate, dissolve it in 300mL of dimethylformami...

Embodiment 2

[0039] In this embodiment, the preparation method of the medium and low temperature gel for formation plugging comprises the following steps:

[0040] Step 1. Synthesis of cationic crosslinking agent-poly(4-vinylbenzenetetrahydrothiophene tetrafluoroborate)

[0041]S1: Add 2.5mol 4-vinylbenzyl chloride and 1.0mol tetrahydrothiophene to methanol, keep stirring in a dark environment for 4 days, remove methanol by vacuum distillation, wash with a large amount of acetone 3 times and dry , to obtain a light yellow powdery solid, dissolve the solid in 30g of water, add 2mol sodium tetrafluoroborate, stir at room temperature for 1.5 hours, then filter to obtain a precipitate, wash the precipitate with a small amount of cold water and 1000mL ether, and dry to obtain a white Powdered solid particles, that is, 4-vinylbenzenetetrahydrothiophene tetrafluoroborate;

[0042] S2: Weigh 2mol of 4-vinylbenzenetetrahydrothiophene tetrafluoroborate, dissolve it in 300mL of dimethylformamide, an...

Embodiment 3

[0046] In this embodiment, the preparation method of the medium and low temperature gel for formation plugging comprises the following steps:

[0047] Step 1. Synthesis of cationic crosslinking agent-poly(4-vinylbenzenetetrahydrothiophene tetrafluoroborate)

[0048] S1: Add 0.06mol 4-vinylbenzyl chloride and 0.06mol tetrahydrothiophene to methanol, keep stirring in a dark environment for 4 days, remove methanol by vacuum distillation, wash with a large amount of acetone 3 times and dry , to obtain a light yellow powdery solid, dissolve the solid in 20g of water, add 0.12mol sodium tetrafluoroborate, stir at room temperature for 1 hour, then filter to obtain a precipitate, wash the precipitate with a small amount of cold water and 100mL ether, and dry to obtain White powdery solid particles, that is, 4-vinylbenzenetetrahydrothiophene tetrafluoroborate;

[0049] S2: Weigh 0.05mol 4-vinylbenzenetetrahydrothiophene tetrafluoroborate, dissolve it in 250mL dimethylformamide, and ad...

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Abstract

The invention provides a medium-low temperature gel based on a cationic cross-linking agent and used for stratum plugging. The cationic cross-linking agent is poly(4-vinylbenzene tetrahydrothiophene tetrafluoroborate), and the medium-low temperature gel for stratum plugging is prepared by the following steps: dissolving polyacrylamide and the cationic cross-linking agent in water, and fully and uniformly stirring under the condition of heating to 22-90 DEG C to obtain a mixed solution; adjusting the pH value of the mixed solution to be 3-11, continuously stirring uniformly, and standing at constant temperature sufficiently to obtain the medium-low temperature gel for stratum plugging. The cationic cross-linking agent and polyacrylamide are subjected to covalent cross-linking in a large temperature range (including medium and low temperature), so that the medium-low temperature gel for stratum plugging, which has relatively good salt resistance and mechanical properties, is further provided.

Description

technical field [0001] The invention relates to the technical field of petroleum underpressure operation, relates to a medium-low temperature gel used for formation plugging, and in particular to a cationic cross-linking agent. Background technique [0002] In the process of drilling and completion or workover operations in oil and gas fields, sufficient and safe balance pressure must be provided to ensure the smooth progress of construction operations. Conventional formation pressure plugging is generally a mechanical isolation device, but as the downhole environment becomes more and more complex, mechanical isolation devices are prone to problems such as insufficient plugging, ineffective switching, or poor sealing. Gel materials with "solid-like" characteristics can be used to replace mechanical isolation devices to isolate oil and gas pressure in formations. [0003] Gels are three-dimensional hyperhydration macromolecular networks cross-linked by permanent or reversibl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F112/14C09K8/512C09K8/88
CPCC08F112/14C09K8/512C09K8/5083C09K8/887C09K8/882
Inventor 程立廖锐全李振
Owner YANGTZE UNIVERSITY
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