Method for improving viscosity stability of oil field polymer flooding

A viscosity stability, polymer technology, applied in drilling compositions, chemical instruments and methods, etc., can solve the problem of high usage of hexamethylenetetramine, reduce the formation of hydroxyl radicals, reduce losses, The effect of reducing the content

Active Publication Date: 2013-03-06
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the crosslinking agent in this invention needs to be prepared in advance before the polymerization, and additional supporting devices need to be provided; and the amount of hexamethylenetetramine used is too high

Method used

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  • Method for improving viscosity stability of oil field polymer flooding
  • Method for improving viscosity stability of oil field polymer flooding
  • Method for improving viscosity stability of oil field polymer flooding

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Polyacrylamide: The molecular weight is 18 million, and the degree of hydrolysis is 26%.

[0026] Polymerized water: the total salinity is 362mg / L, Na + 、K + The concentration is 79.2mg / L, Ca 2+ The concentration is 23.4mg / L, Mg 2+ The concentration is 9.5mg / L, Cl - The concentration is 104mg / L, SO 4 2- The concentration is 20mg / L, HCO 3 - An aqueous solution with a concentration of 126mg / L and a pH value of 7.8.

[0027] Experimental method: at room temperature, add 50mg / L thiourea to the polycondensation water, stir for 2 hours, and let it stand for 1 hour; Stir in poly water, the initial stirring speed is 300 rpm, after the polymer particles are fully dispersed, control the stirring speed at 120 rpm, stir for 2 hours, and let stand for 6 hours, and finally prepare a concentration of 1500mg / min The polymer solution of L; add hexamethylenetetramine in the polymer solution, make the concentration of hexamethylenetetramine in the solution reach 150mg / L, stir 0.5...

Embodiment 2

[0030] Polyacrylamide and polyhydric conditions are the same as in Example 1.

[0031] The experimental method is the same as in Example 1, but the concentration of thiourea added to the polycondensation water reaches 100mg / L. The viscosity retention rate of the obtained sample after storage at 80° C. for 30 days was 56.0%.

Embodiment 3

[0033] Polyacrylamide and polyhydric conditions are the same as in Example 1.

[0034] The experimental method is the same as in Example 1, but the concentration of thiourea added to the polycondensation water reaches 150mg / L. The viscosity retention rate of the obtained sample after storage at 80° C. for 30 days was 93.4%.

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Abstract

The invention provides a method for improving the viscosity stability of oil field polymer flooding. With the method, a problem of polymer viscosity reduction under high-temperature and oxygen-containing conditions is solved. The invention adopts anionic polyacrylamide, hexamethylenetetramine, and thiourea. Thiourea is dosed before polymerization, and hexamethylenetetramine is dosed after polymerization, such that polymer solution viscosity stability is greatly improved. With the invention provided by the invention, displacing fluid viscosity stability is greatly improved, and polyacrylamide high-temperature resistance and oxidation resistance are improved. The process is simple, the cost is low, and the material is easy to transport and to store.

Description

technical field [0001] The invention relates to polymer flooding in tertiary oil recovery, in particular to a method for improving viscosity stability of oilfield polymer flooding. Background technique [0002] In tertiary oil recovery technology, there are many ways to enhance oil recovery, such as injecting surfactant, injecting polymer thickened water, injecting alkali water flooding, injecting CO 2 flooding, alkali plus polymer flooding, inert gas flooding, hydrocarbon miscible flooding, oil layer combustion and steam flooding, etc. At present, polymer flooding is generally used in the production process of high water-cut oilfields in China to increase oil recovery; the mechanism of polymer flooding is to add polymers to the injected water to increase the viscosity of the displacement phase, adjust the water absorption profile, and increase Phase replacement sweeps volumes to enhance ultimate recovery. my country's crude oil has a high viscosity, which is more suitable...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/588
Inventor 邢毅曹宗仑张英雄平春霞邢琳马友富
Owner CHINA PETROLEUM & CHEM CORP
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