Hydrophobic association micro-crosslinking polymer oil displacement agent and preparation method thereof

Abstract

The present invention discloses one kind of hydrophobic associated and micro cross-linking polymer oil displacing agent and its preparation process. The hydrophobic associated and micro cross-linking polymer oil displacing agent is prepared through compounding water solution of water soluble hydrophobic associated copolymer of acrylamide / (vinyl benzene sulfonic acid and / or 2-acryl amido-2-methyl propyl sulfonic acid) / (C0-C18 alkyl styrene and / or p-phenyl styrene) in 0.1-2 g / l concentration, cross-linking agent solution in 0.01-1.0 g / l concentration, surfactant solution in 0.01-8 mmol / l concentration and solution of heat stabilizer thiourea in 0.005-1.0 g / l concentration; mixing in a mixer with stirrer and regulating the solution pH to 4-11 to obtain the polymer oil displacing agent. The polymer oil displacing agent cross links during flowing in oil reservoir to increase solution viscosity, and has excellent application foreground in oil reservoir development.

Description

1. Technical field [0001] The invention relates to a hydrophobic association cross-linked polymer oil displacement agent and a preparation method thereof, belonging to the fields of polymer materials and oil field chemistry. 2. Technical background [0002] Polymer flooding is one of the important technologies for enhancing oil recovery, and the polymer oil flooding agent currently used in industry is still mainly partially hydrolyzed ultra-high molecular weight polyacrylamide (HPAM), and its viscosity-increasing ability mainly depends on High molecular weight, but for this viscosity-increasing approach, the shear degradation of macromolecules is prone to occur during the dissolution and injection process, especially in the injection of low-permeability reservoirs, and the molecular chain size is large, which is easy to block low-permeability reservoirs reservoir pores. In addition, due to poor temperature resistance and salt resistance, the application of HPAM in high temp...

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Problems solved by technology

Geng Tongmou et al., Fine Chemical Industry 2006, 23 (8): 747-751, synthesized a ternary hydrophobic association water-soluble polymer poly(acrylamide / sodium acrylate / N, N-diallyltetradecylamine (P( AM / NaAA / DiAC 14 ), and studied its solution properties, but the critical association concentration of the copolymer is relatively high, and the apparent viscosity of the solution at a mass concentration of 4g / L is still not high, and with the increase of temperature, the thermal movement of molecules is intensified , the hydrophobic association between molecules is severely damaged, and the solution viscosity drops significantly

In addition, most of the current hydrophobic monomers are hydrolyzed at a temperature higher than 80 ° C, resulting in the loss of their hydrophobic association function, making the anti-aging performance of the polymer solution poor

Moreover, although this type of polymer exhibits a salt thickening effect within a certain range of salt concentration, due to the low molecular weight and the shielding effect of salt, compared with the solution viscosity in fresh water, the viscosity of this type of polymer in salt water decreases. high rate

Lv Xin et al., Polymer Materials Science and Engineering, 2006, 22(3): studied and compared organoaluminum and phenolic cross-linked HPAM weak gel systems, and found that due to the existence of cross-linked structures, the rigidity of polymers is enhanced and the difficulty of conformational changes is increased. , HPAM weak gel system has high solution viscosity at high temperature and high salinity, but the temperature is limited to (75-90°C), and the solution viscosity drops significantly after the temperature is higher than 90°C

In addition, HPAM cross-linked polymers are easy to plug low-permeability reservoirs