Impact of tailored water chemistry aqueous ions on foam stability enhancement

Generating strong and stable foam is necessary to achieve in-depth conformance control in the reservoir. Besides other parameters, the chemistry of injection water can significantly impact foam generation and stabilization. The tailored water chemistry was found to have good potential to improve foam stability. The objective of this study is to extensively evaluate the effect of different aqueous ions in the selected tailored water chemistry formulations on foam stabilization. Bulk and dynamic foam experiments were used to evaluate the impact of different tailored water chemistry aqueous ions on foam generation and stabilization. For bulk foam tests, the stability of foams generated using three surfactants and different aqueous ions was analyzed using bottle tests. For dynamic foam experiments, the tests were conducted using a microfluidic device. The results clearly demonstrated that the ionic content of aqueous solutions can significantly affect foam stabilization. The results revealed that the foam stabilization in bulk is different than that in porous media. Depending on the surfactant type, the divalent ions were found to have stronger influence on foam stabilization when compared to monovalent ions. The bulk foam results pointed out that the aqueous solutions containing calcium chloride salt (CaCl2) showed longer foam life with the anionic surfactant and very weak foam with the nonionic surfactant. The solutions with magnesium chloride (MgCl2) and CaCl2 salts displayed higher impact on foam stability in comparison with sodium chloride (NaCl) with the amphoteric alkyl amine surfactant. Less stable foams were generated with aqueous solutions comprising of both magnesium and calcium ions. In the microfluidic model, the solutions containing MgCl2 showed higher resistance to gas flow and subsequently higher mobility reduction factor for the injection gas when compared to those produced using NaCl and CaCl2 salts. This experimental study focusing about the role of different aqueous ions in the injection water on foam could help in better understanding the foam stabilization process. The new knowledge gained can also enable the selection and optimization of the right injection water chemistry and suitable chemicals for foam field applications.

Foaming Properties and Foam Structure of Produced Liquid in Alkali/Surfactant/Polymer Flooding Production

Alkali/surfactant/polymer (ASP) flooding process is proven to be vitally effective for enhancing oil recovery (EOR) in the oil industry. However, foaming behavior is generated by the breakthrough of chemical agents in the produced liquid and is increasingly concerned as a terrible problem during production. A set of experiments was recently performed to investigate the effects of foaming properties of ASP flooding produced liquid. The factors affecting foaming capacity and foam stabilization were discussed, and the differences in foaming properties of produced liquid between strong base and weak base ASP flooding were firstly compared. The results indicated that in addition to temperature and pressure, the concentrations of chemical agents in the produced liquid were responsible for the foaming properties and foam stabilization. The foaming capacity could enhance 3∼7% at 45 °C compared with a lower temperature of 35 °C. The average comprehensive index of the foam could increase from 2.2×105 at 29 psi to 2.5×105 at 73 psi. The regularity of Plateau borders was highlighted at higher pH and surfactant concentration, and thus facilitated the foam stabilization. The liquid film thickened and its shape expanded to the state of maintaining foam stabilization with the increase of polymer concentration. Furthermore, the foaming behavior of produced liquid in strong base ASP flooding production is much more troublesome than that in weak base ASP flooding production. This study is significant in that it further supports the development of efficient treatment technology for produced liquid in oilfield.

Nanoparticle and Bioparticle Deposition Kinetics: Quartz Microbalance Measurements

Controlled deposition of nanoparticles and bioparticles is necessary for their separation and purification by chromatography, filtration, food emulsion and foam stabilization, etc. Compared to numerous experimental techniques used to quantify bioparticle deposition kinetics, the quartz crystal microbalance (QCM) method is advantageous because it enables real time measurements under different transport conditions with high precision. Because of its versatility and the deceptive simplicity of measurements, this technique is used in a plethora of investigations involving nanoparticles, macroions, proteins, viruses, bacteria and cells. However, in contrast to the robustness of the measurements, theoretical interpretations of QCM measurements for a particle-like load is complicated because the primary signals (the oscillation frequency and the band width shifts) depend on the force exerted on the sensor rather than on the particle mass. Therefore, it is postulated that a proper interpretation of the QCM data requires a reliable theoretical framework furnishing reference results for well-defined systems. Providing such results is a primary motivation of this work where the kinetics of particle deposition under diffusion and flow conditions is discussed. Expressions for calculating the deposition rates and the maximum coverage are presented. Theoretical results describing the QCM response to a heterogeneous load are discussed, which enables a quantitative interpretation of experimental data obtained for nanoparticles and bioparticles comprising viruses and protein molecules.