Effect and mechanism of rheological properties and structure of a novel hydrophobically associating polymer on sand sedimentation rate

With hydrophobic associating polymer (BCG-1) and anionic surfactant sodium dodecyl benzene sulfonate (SDBS) solution as the object, this work studies the different polymer concentration and surfactant concentration on the influence law of fluid properties and examines the sand sedimentation rate and the correlation of fluid properties. After the liquid was tested by electron microscope and rheometer, it was found that the interaction between the surfactant and the polymer is with phases, which provided different angles for revealing the change rule of the deposition rate of sand. When the concentration of SDBS solution is in the second phase (0.05–0.2%), although the system property changes slightly and the microscopic morphology does not change greatly, the deposition rate of sand still decreases significantly. Relaxation time spectrometry explains that the reduction in the sedimentation rate of the sand is caused by the shift of the polymer chain motion mode, whereas the phase angle can clearly manifest this change, and the phase angle is highly correlated with the deposition rate of sand.

Adsorption Characteristics of Polymer Solutions on Media Surfaces and Their Main Influencing Factors

In practical applications, the chemical and physical adsorption of a polymer solution greatly affects its action mode and effect. Understanding the adsorption mechanism and its influencing factors can help to optimize the application mode and ensure application efficiency. Three types of polymer solutions—partially hydrolyzed polyacrylamide (HPAM), hydrophobically associating polymer (AP-P4), and dendrimer hydrophobically associating polymer (DHAP), which are viscoelastic liquids—were used as sorbates to study their adsorption by a sorbent such as quartz sand. The effects of the solution concentration, contact time, particle size of quartz sand, solid–liquid ratio, and fluid movement on the adsorption capacity of the polymer solutions were examined. The results showed that HPAM presents a typical Langmuir monolayer adsorption characteristic, and its adsorption capacity (per unit area) is 1.17–1.62 μg/cm2. The association enhances the interactions of the AP-P4 and DHAP solutions, and they present multilayer characteristics of first-order chemical adsorption and secondary physical molecule adsorption. Moreover, the dendrite structure further increases the adsorption thickness of DHAP. Hence, the adsorption thicknesses of AP-P4 and DHAP are four and six times that of HPAM, respectively. The adsorption of the three polymers is consistent with the influence of fluid motion and decreases with increasing fluid velocity. However, the larger the thickness of the adsorption layer, the clearer the influence of the flow, and the higher the decrease in adsorption capacity. Optimizing the injection rate is an effective method to control the applications of a polymer in porous media.