Gelation mechanism and rheological properties of polyacrylamide crosslinking with polyethyleneimine and its plugging performance in air‐foam displacement

Abstract

Gels based on polyacrylamide crosslinking with polyethyleneimine have attracted attention because of their resulting high strength and good thermal stability. This study investigated the gelation mechanism of the polymeric gel and its plugging performance in air-foam flooding. An optic microrheology analyzer was used to monitor the gelation process. The crosslinking reaction occurred in two steps, as determined from the elasticity factor curves, and the polymeric gels adopted a semisolid state from solution, as determined from the solid liquid balance curves. The elastic modulus values were higher than the viscous modulus values, indicating that mature gels were elastic-based materials. The yield stress increased gradually with increasing polymer dosage, which was consistent with the breakthrough pressure and the trend of displacement pressure. The mature gels showed significant thixotropy. In the core displacement test, the preferred injection volume of the gel was 0.1 pore volume, and the stable pressure of the foam flooding was increased by about three times after the core was plugged. The blocking effect for cores with small original permeability was better than that with large permeability. The best blocking resulted from simultaneous treatment of both ends of the cores, followed by front-end treatment and rear-end treatment.

Competition between Chain Extension and Crosslinking in Polyamide 1012 during High-Temperature Thermal Treatments as Revealed by Successive Self-Nucleation and Annealing Fractionation

“…The results in Figure c revealed that the elasticity modulus deviated from the scaling law in the terminal region and developed a plateau at low frequencies. This result indicated that a crosslinked structure was formed during the high-temperature isothermal treatment. − Hence, was this crosslinking process physical or chemical in nature? Was it reversible or irreversible?…”

Rational Tuning of Binding Properties of Pillar[5]arene-Based Crystalline Material by Synergistic Effect and Its Application for Fluorescent Detection and Adsorption of 1,2-Ethylenediamine

“…The intermolecular π···π interactions were also supported by macroscopic viscosity index (MVI) experiments. Rheolaser Lab Diffusing Wave spectroscopy was utilized to compare the MVI of PQ8 , EDA , and PQ8@2EDA in the CHCl 3 solution. The higher the MVI, the slower the particles move in the solution .…”

Lanthanide-Mediated Cyclodextrin-Based Supramolecular Assembly-Induced Emission Xerogel Films: A Transparent Multicolor Photoluminescent Material

“…In addition, Rheolaser Lab Diffusing Wave Spectroscopy was utilized to compare the gelation mechanism of WCB-α-CD and WCB-α-CD@Ms . As shown in Figure a, the lower the plateaus of the mean squared displacement (MSD), the higher the elasticity of the gels.…”