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Research On Structure Of Crosslinking System And Rheology For HPAM Weak Gels

Posted on:2017-02-18Degree:MasterType:Thesis
Country:ChinaCandidate:L ZhangFull Text:PDF
GTID:2271330488960275Subject:Chemical Engineering and Technology
Abstract/Summary:PDF Full Text Request
With the increased of water content in oil field, it was proposed to adjust the water absorption profile in the deep reservoir, to forced the liquid flow, improved the effect of water injection and the oil recovery, so as to promote the rapid development of deep profile control.Weak gels had been widely used in oil fields in deep profile control because of lower costs,longer gel time, and higher gel strengths. It was provided the scientific basis for the weak gel profile control application in research on weak gels for rheology, viscoelastic properties and shear in the process of formation migration.This paper focused on the mechanism of microstructure and gelation effect of the ions of Fe3+, salinity, main group concentration, additives for HPAM weak gel. Rheological model of HPAM weak gels of gel was established and shear stability and viscoelasticy was studied by HAKKE rheometer 6000.The experimental results showed that the salinity of the water used for the preparation of organic chromium cross-linked HPAM weak gel should be less than 8000 mg/L, otherwise it will affect the properties of gelation. when sodium lignosulfonate, carboxymethyl cellulose and chitosan were added to the original HPAM weak gel, gelation time of HPAM weak gels was delayed, the size of gel structure unit was reduced in acceleration period by microscope.It had no differences in molecular aggregates with close association in stable period. The gelation time was faster and the gel strength was larger when xanthan gum was added, which can be used for profile control in near well. The molecular aggregates are self-similar dendritic fractal images regardless of the change for concentration of the HPAM and the crosslinking agent.Rheology studies proved that HPAM weak gel adding sodium lignin sulfonate,carboxymethyl cellulose, chitosan and xanthan gum system were in accord with the power law equation. Additive did not reduce the degree of shear thinning for HPAM weak gel, but the ability of viscosity under shearing was strongger with the addition of a xanthan gum in HPAM weak gel system. Mechanical shearing was beneficial for the induction period of the crosslinked polymer gel, but the shear has no advantage for viscosity recovery of weak gel in the acceleration period. Within the linear viscoelastic region, Elastic dominated in the salinity of prepared water below 6000 mg / L for weak gel, 8000 mg / L was a typical viscoelasticity.The addition of carboxymethyl cellulose and xanthan gum can increase the elasticity of theweak gel, and the elasticity was higher than that of the HPAM weak gel,and the three weak gels were viscoelastic body, which were suitable for profile control and water plugging.
Keywords/Search Tags:HPAM weak gels, the deep profile control, molecular aggregates, shear, viscoelasticity
PDF Full Text Request
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