Papers by Keyword: Polymer

Abstract: In the process of polymer flooding in porous media, polymer was detained due to interactions between surface adsorption and polymer molecules, and this could lead to negative effects on oil displacement. For polymer adsorption in Xinjiang conglomerate reservoir, HPLC analysis was adopted to study the static and dynamic laws. Results have showed that the adsorption process could be divided into 3 stages: rapid growth, slow growth and stable state. With the loss of polymer molecular weight, equilibrium adsorption quantity reduces gradually. The adsorption amount is different for the same polymer on four types of oil sands. For equilibrium adsorption, the maximum value is argillaceous sandstone, followed by conglomeratic sandstone.The third is argillaceous gravel, and the minimum is sand gravel. For polymer flooding in conglomerate cores, the dynamic retention amount of seriate conglomerate is much greater than that of fine particle conglomerate. These data have provided reference for project design of polymer flooding in conglomerate reservoir.

Abstract: A novel smart gel based on interpenetrating network of anionic polymer and surfactant was investigated. A supramolecular assembly structured gel is formed by associating polymer side chain with wormlike micelle of surfactant. The physical interaction of val der vaal and hydrogen bonding force between surfactant and polymer gives a strong viscoelastic gel at evaluated temperature. The viscoelastic properties and gel structure were characterized by dynamic rheometer and cryo-TEM. The polymer and VES complex gel is highly elastic, which elastic moduli G’ is higher than loss moduli G’’ at low angular frequency, 0.1 rad/s, in high temperature. The total concentration of surfactant and polymer is low which is economically to use in industries.

Abstract: Low-frequency acoustic method, studies of viscoelastic properties of polymers tetrazolecontaining. It was shown that the introduction of modifiers KCl and KNO₃ has a different effect on the dynamic and mechanical characteristics tetrazolecontaining polymers. It is noted that such changes are related to the restructuring of the molecular organization of cross-linked polymers.

Abstract: Sodium bicarbonate was modified with citric acid by solution coating method, and used to increase the foaming temperature and narrow the range of decomposition temperature. The thermodynamic parameters of sodium bicarbonate and modified sodium bicarbonate were studied by DSC and TG. After the modification, the initial decomposition temperature of sodium bicarbonate raised from 112.6 ^oC to 146.9 ^oC, endothermic peak temperature from 150.5 ^oC to 165.9 ^oC, the range of decomposition temperature narrows from 56.2 ^oC to 31.5 ^oC. After modification, sodium bicarbonate shows faster rate of decomposition.

Abstract: Although supercritical CO₂ fracturing has incomparable advantages compared to hydraulic fracturing as a new recreating technology of shale gas reservoir, the application of this technology has been limited by the low viscosity and weak carrying capacity of proppant. It’s critical to enhance the viscosity of supercritical CO₂ by adding thickening agents. Thickening agents for supercritical CO₂ that have been studied by researchers mainly contained polymers, small molecular compounds and surfactants. Thickening agents that match with CO₂ are characterized by low cohesive energy density, low polarity, high free volume and Lewis base. It’s necessary to study the interaction between thickening agents and CO₂ by molecular simulation to design inexpensive, green thickening agents which could increase the viscosity of supercritical CO₂ remarkably under low concentration.

Abstract: Polymer modified cementitious waterproof coating is an important construction material. In this paper, starting from the classification and choice of waterproof coatings, the importance, advantages and application prospects of the polymer cement waterproof coatings were discussed. The approaches for solving the existing problems and limitations of polymer modified cementitious waterproof coatings were put forward.

Abstract: In drilling and well completion operations, drilling fluid is a crucial element as it is employed for the purposes of several functions. The main functions of drilling fluid are to control formation pressure, maintain the wellbore stability, transport the cuttings up to surface to clean the borehole bottom as well as to lubricate and cool the drill bit. Moreover, it is used to minimize the drilling damage to reservoir and suspend cuttings when the pumping is stop, hence it will not falling back down the borehole. The purpose of this study is to formulate new drilling mud formulation modified with nanosilica. Six samples of water based mud (WBM) were prepared using three types of polymers, (Xanthan Gum, Hydro Zan Plus and Hydro Star HT), starch and nanosilica. Basic rheological tests such as density, viscosity and pH were carried out. The density test was carried out using mud balance meanwhile the pH test was using pH meter. The plastic viscosity, yield point and gel strength tests were carried out using viscometer. Besides that, physical observation was also performed for as the stability test. The results concluded that water based mud incorporated with polymer Hydro Zan Plus and nanosilica can be a potential candidate to be commercialized as a smart nanodrilling fluid.

Abstract: The present paper is concerned with constitutive modeling of the compressive stress-strain behavior of selected polymers at strain rates from 10^-3 to 10³/s using a modified Ramberg-Osgood equation. High strain-rate compressive stress-strain curves up to strains of nearly 0.08 for four different commercially available extruded polymers were determined on the standard split Hopkinson pressure bar (SHPB). The low and intermediate strain-rate compressive stress-strain relations were measured in an Instron testing machine. Six parameters in the modified Ramberg-Osgood equation were determined by fitting to the experimental stress-strain data using a least-squares fit. It was shown that the monotonic compressive stress-strain behavior over a wide range of strain rates can successfully be described by the modified Ramberg-Osgood constitutive model. The limitations of the model were discussed.

Abstract: High-speed tensile tests were carried out to investigate strain rate effect on both yield stress and failure strain using ASTM D1822 Type-S specimens made of polycarbonate. Based on test results, parameters for a material model suitable for polymers are determined, and numerical analysis is carried out to simulate test results. The material model is used to simulate tensile test using a dog-bone specimen and Charpy test other than the tensile test of Type-S specimens. It is found that good predictions can be obtained when rate dependent material parameters are used. Further, the high-speed tensile test considered in the present study is suitable for selection of parameters for material modeling of polymers for impact analysis.

Abstract: In this paper we analyze, using the Finite Element Method, the process of brittle-ductile transition in the failure mode observed in polycarbonate notched specimens under impact loads. In order to analyze this transition we have implemented, through a user subroutine, a damage model which combines a tensional fracture criterion and an energetic, acting simultaneously. The competition between both criteria predicts the difference in material behavior from a critical impact velocity, and how this transition is produced on different planes through the thickness of the specimen. These results show the necessity of employing three-dimensional models for its study.