Numerical calculation of intermolecular bonds under the action of ultrasonic cavitation

The linear model of macromolecules was proposed. Expression for probability of macromolecules breakup under ultrasonic cavitation action was obtained. The fractional composition and viscosity of uncured polymer were calculated. As a result of the calculations, it was evaluated that the cavitation-acoustic effect for a time of no more than 1 min at an vibration intensity of at least 6 W/cm2 and an initial viscosity of 0.2 Pa· s reduces the viscosity of polymers by at least 8 times. At the same time, it was theoretically revealed that the cavitation-acoustic effect is also capable of reducing the viscosity of polymers with an initial viscosity of more than 1 Pa·s up to 4 times.

Study on Formulation with Lower Initial Viscosity Gel/Alkali/Surfactant/Polymer After Polymer Flooding and Scenario Design of Field Test

The blocks of polymer flooding have gradually entered into the stage of chase water flooding after polymer flooding in Daqing Oilfield and the comprehensive water cut is close to the exploitation limit of 98%. So it is urgent to develop some new technologies to further enhance oil recovery after polymer flooding. On the basis of laboratory research, a field test of alkali/surfactant/polymer flooding was carried out after polymer flooding in Daqing Oilfield in 2015, which achieved good development effect, but the polymer concentration was relatively large. Based on the field test of alkali/surfactant/polymer flooding, a new technology of the lower initial viscosity gel/alkali/surfactant/polymer flooding has further been studied according to the technical route combining plugging, adjusting and displacing, which can reduce the polymer dosage greatly under the premise of ensuring good oil displacing effect. In this paper, some laboratory studies are carried out, which realize significant technology breakthrough. Firstly, the adjusting and plugging agent of lower initial viscosity gel is screened out, which can be injected into the high permeability layers of low flow resistance like the water and migrate to the deep location of the high permeability layers and then gelatinize on spot. Therefore it can plug high permeability layers effectively and does not pollute the middle and low permeability layers at the same time. Secondly, the injection parameters of lower initial viscosity gel/alkali/surfactant/polymer system are optimized. The results of laboratory experiments show that the lower initial viscosity gel/alkali/surfactant/polymer system can enhance oil recovery by 13.5% OOIP under the optimal injection parameters, which is 1.2% OOIP more than that of the alkali/surfactant/polymer flooding and can save polymer dosage by 17.8%. In view of the good results obtained in laboratory experiments, the scenario design of field test is carried out and the incremental oil recovery is 10.1% OOIP predicted by numerical simulation. The field test is expected to start chemical flooding in 2021.

Experimental Investigation of a Novel Nanosilica for Blocking Unwanted Water Production

Nanotechnology is the design and application of engineered nanoparticles with one minimum dimension in the range of 1 to 100 nanometers. To achieve a specific target, innovative methods are highly required to overcome the challenges in the oil and gas industry, such as undesired water production. Herein, we present an advanced nanosilica, a new eco-friendly, cost-effective, and promising approach to control undesirable water production. The objective of this work is to evaluate our nanofluid system that can be used for water management in different water production mechanisms, including: high permeability streak, wormhole, and fractured reservoirs. A systematic evaluation of novel nanosilica/activator for water shut-off application requires an examination of the chemical properties before, during, and after gelation at given reservoir conditions. The placement of this water shut-off system is highly dependent on gelation time and viscosity. Therefore, we emphasized in this study on investigating these gelation kinetics by conducting extensive rheology experiments at varied temperatures and activator concentrations. We have looked into evaluating the optimum breaker for the gel as a contingency plan for improper placement. Measurements of the nanosilica fluid’s initial viscosity exhibited a low viscosity, less than 10 cP at normal temperature and pressure (NTP) conditions; this provides significant benefit for mixing at surface and pumping requirements for pilot testing. The nanosilica gelation time can be tailored by adjusting activator concentration to match field job design at a given temperature, which is more than 200°F. The gelation time revealed an exponential relationship with temperature and reversible proportionality. The nanosilica gel proved to be a thermally stable fluid system along with different activation ratios. For breaker tests, the gellant fluid showed complete breakdown at altered temperatures to mimic downhole conditions. Our lab observations conclude that nanosilica fluid is verified to be acceptable as a water shut-off system for field applications. This novel nanofluid system is a promising technology to control water production from oil wells. The system has low initial viscosity that can be injected in porous media without hindering the injectivity and getting at risk of fracking the sand. In case of inappropriate placement, the fluid can break down entirely using a non-damaging chemical breaker instead of using mechanical approaches that might damage the completion.

STUDY OF THE RHEOLOGY OF WATER-OIL EMULSIONS AT NEGATIVE TEMPERATURES

В той или иной степени, все предприятия, осуществляющие добычу, транспорт и хранение нефти в емкостях, сталкиваются с необходимостью утилизации устойчивых эмульсий промежуточного слоя. С учетом климатических условий северных регионов имеются особенности в процессах образования, разделения, переработки стойких водонефтяных эмульсий. Исследование вязкостно-температурных свойств и температуры застывания позволит разработать эффективные технологические решения по их хранению и внутрипромысловой перекачке. В работе представлены результаты измерения вязкости эмульсий нефтей Ванкорского, Тагульского, Куюмбинского месторождений, различающихся по химическому составу и исходной вязкости, и соответствующих пластовых вод с содержанием от 10 до 50 % об., при температурах от плюс 20 оС до температуры застывания, а также после выдержки в течение 7 суток при отрицательных температурах. All companies producing, storing, or transporting oil, to one degree or another, face the negative consequences of the formation of stable oil-water emulsions. Due to the climatic conditions of the northern regions, there are peculiarities in the processes of formation, separation, processing of persistent oil-water emulsions. The study of the viscosity and pour point of emulsions will make it possible to develop effective technological solutions for the storage and pumping of such emulsions in the field. The article presents the results of measuring the viscosity of emulsions of oils from Vankorskoye, Tagulskoye, Kuyumbinskoye fields, differing in chemical composition and initial viscosity, and corresponding formation waters with a content of 10 to 50 vol.%. at a temperature from plus 20 ° C to the solidification point, as well as after thermostating for 7 days at negative temperatures.

Structuring of hydroxy-terminated polydimethylsiloxane filled by fumed silica

The term “structuring” used in silicone rubber describes a phenomenon of the increase in the viscosity of polydimethylsiloxane filled with silica during storage, which limits the applications of the room temperature vulcanized (RTV) silicone rubber in the field of aerospace and military. In this pursuit, the present study was envisaged to solve the problem of structuring of the RTV. A solvent-free method was used to hydrophobize the hydrophilic silica with hexamethyldisilazane. An RTV composition prepared using eight parts of hydrophobic silica with 2.91% C content exhibited a viscosity of less than 100 Pa s, with no significant change in 21 days. In contrast, eight parts of the hydrophilic fumed silica showed an initial viscosity of RTV to be greater than 2,000 Pa s. Silica samples with different adsorbed water content were used to prepare the RTV compositions. It was found that the viscosity of the RTV prepared using the sufficiently dried silica was 5.6 times lower than that of the wet silica. The “dissolution” model of the silica–silica hydrogen bonds in water was proposed. Furthermore, the change in the viscosity of the RTV compositions at different temperatures in the range of −15°C to 30°C was studied. The viscosity of RTV stored at –15°C for 34 days did not change significantly, whereas that stored at room temperature increased from 100 to 1,710 Pa s within 21 days.

Impact of Acrylate and 2-Acrylamido-Tertiary-Butyl Sulfonic Acid Content on the Enhanced Oil Recovery Performance of Synthetic Polymers

Summary Polymer flooding is a mature enhanced oil recovery (EOR) technology that has seen increasing interest over the past decade. Copolymers of acrylamide (AMD) and acrylic acid (AA) have been the most prominent chemicals to be applied, whereas sulfonated polymers containing 2-acrylamido-tertiary-butyl sulfonic acid (ATBS) have been used for higher temperature and/or salinity conditions. The objective of this study was to generate guidelines to aid in the selection of appropriate polyacrylamide chemistry for each field case. Our focus was in sandstone fields operating at the upper end of AA-AMD temperature tolerance, where there is a decision as to whether sulfonation is required. The performance of the polymer throughout the whole residence time in the reservoir was considered because the macromolecule can undergo some changes over this period. Several key properties of nine distinct polymer species were investigated. The polymers consisted of AA-AMD copolymers, AMD-ATBS copolymers, and AMD-AA-ATBS terpolymers (up to 15 mol% ATBS). The polymer solutions were studied both in their original state as they would be during the injection (initial viscosity, initial adsorption, and in-situ rheology), as well as in the state in which they are expected to be after the polymer has aged in the reservoir (i.e., in a different state of hydrolysis with corresponding changes in viscosity retention and adsorption after aging for various time periods). We note that the combination of viscosity retention and adsorption during the in-situ aging process has not been typically investigated in previous literature, and this is a key novel feature of this work. Each of the above parameters has an impact on the effectiveness and the economic efficiency of a polymer flooding project. The majority of the work was carried out in seawater (SW) at a temperature of 58°C. Under these conditions, AMD-AA samples showed similar solution viscosity at 5 to 30% AA. When the AA-AMD polymer solutions were aged at elevated temperature, the AA content steadily increased because of hydrolysis reactions. When the AA content was 30 mol% or higher, the viscosity started to decrease, and the adsorption started to increase as the polymer solution was aged further. Thermal stability improved when ATBS was included in the polymer structure. In addition, sulfonated polyacrylamide samples showed constant initial viscosity yields and decreasing initial adsorption with increasing ATBS content. The samples showed that the maximum observed apparent in-situ viscosity increased when the bulk viscosity and relaxation time of the solution increased. The information generated in this study can be used to aid in the selection of the most optimal polyacrylamide chemistry, which may not necessarily be the standard 30% AA and 70% AMD copolymer, for sandstone fields operating with moderate/high salinity brines at the upper end of AA-AMD temperature tolerance.

Structures, Properties and Potential Applications of Corncob Residue Modified by Carboxymethylation

In this study, corncob residue (CR) valorization was simply and efficiently realized via carboxymethylation, and its enhanced performance as fillers in urea-formaldehyde (UF) resin was investigated. The structures of corncob residue and carboxymethylated derivative were analyzed by nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), and Raman techniques, respectively. The thermal stability, morphology, viscosity control, and adhesive strength were then investigated to evaluate its performance as fillers in UF resin composite. Similar to commercial flour, carboxymethylated CR could effectively disperse in UF resin. It also exhibited a better initial viscosity control between 30 and 50 °C. The adhesive test analysis showed that the shear strength of resin with carboxymethylated CR addition could reach 1.04 MPa, which was comparable to flour (0.99 MPa) and significantly higher than raw CR (0.45 MPa). Moreover, a low formaldehyde emission was observed.

Research on Reliability of Packaging Materials for PVT Modules

This paper studies the difference in heat transfer and adhesion performance of glass fiber substrate thermal conductive double-sided adhesive, PVC substrate double-sided adhesive, and PET substrate double-sided adhesive to thermal conductive materials and polymer materials in photovoltaic and thermal integrated modules. Studies have shown that the use of glass fiber-based thermally conductive double-sided adhesive to bond polymer materials and thermally conductive materials can achieve the normal use of PVT modules under weather-resistant conditions. Research has shown that glass fiber-based thermally conductive double-sided adhesive has better adhesion than other materials., Initial viscosity, static shear force, thermal conductivity, etc., can realize the normal use of PVT modules under weathering conditions.

Pasting properties of raw and extruded cowpea cotyledons flours

There is little research on the viscosity profile analysis of cowpea cotyledon flour (CCF). Due to the new ways of using pulses grains in the diet, it is important to evaluate the viscoamylographic behavior of raw and processed CCF. The CCF was obtained from the cultivars BRS Guariba and BRS Novaera and evaluated in the Rapid Visco Analyzer (RVA). For raw CCF it was used the “Standard 1” program. The extruded CCF was obtained from the cultivar BRS Guariba, which was processed following a central rotational composite design, combining thermoplastic extrusion temperatures (124; 130; 145; 160; 166 °C) and conditioning moisture (16.2%; 17%; 19%; 21%, 21.8%). The obtained extrusions were ground (Ø > 0.5 mm) and evaluated in the RVA using the program “Extrusion 2”. The raw CCF from BRS Guariba presented higher protein, lipid and mineral content and lower carbohydrate content than BRS Novaera. The raw CCF from BRS Guariba showed lower values of pasting temperature (79.35 °C), viscosity breakdown (103.00 cP) and seatback (1447.33 cP) compared to raw CCF from BRS Novaera. The extrusion process drastically changed all viscosity parameters, increasing the initial viscosity value and decreasing the value of other parameters. The extruded CCF had different pasting properties. CCF extruded at 166 °C and 19% moisture resulted in flours with higher initial viscosity and lower retrogradation values, which can be used as a thickener in food products, in addition to increase nutritional value.