Acceleration of Novel Technology Development for Stabilized Emulsion Treatment in EOR Applications

Separation of stable emulsions produced from chemical enhanced oil recovery (CEOR) in a brownfield production system using conventional 3-phase separators is almost impossible, requiring large quantities of chemical demulsifiers to meet oil production specifications. A new and novel high-voltage high-frequency (HVHF) electro-coalescence (EC) technology has been identified as potential method to enhance separation of EOR produced fluid for improving CEOR implementation feasibility. This paper aims to present results and findings from the recent EC technology development against success criteria and parameters associated for fast-track field application. Electrostatic coalescers are used as an emulsion breaker, crude dehydrator or desalter in production systems and refineries. However, significant developments are required to use this EC technology as a potential treatment technology for tight emulsions/rag layers in CEOR applications. A new prototype of Inline EC was developed and tested in a batch test setup to evaluate the separation efficiency using real crude-brine samples and a cocktail of alkaline-surfactant-polymer (ASP) chemicals. The sensitivities of separation efficiency to different water cut, demulsifier concentration, EC voltage/exposure time, concentrations of alkaline, surfactant and polymer in the brine were measured and optimal process conditions were assessed. The results and findings were evaluated based on defined success criteria and parameters associated with separation efficiency such as volume fractions of the emulsion, oil-in-water (OIW) and water-in-oil concentrations (WIO), respectively. On one of PETRONAS CEOR field case study, the test results show that EC reduced 90% of the tight emulsion. In conclusion, EC leads to a substantial improvement in separation efficiency relative to the case without EC for water cuts below the inversion point. It is also found that the EC treatment without added demulsifier is equally effective in breaking the emulsion as adding a demulsifier without EC treatment, and that EC can potentially minimise or eliminate the application of demulsifiers in the production system.

Development of a model of the optimal temperature mode of the main gas pipeline operation

The influence of the ambient air temperature on changes in the parameters and thermophysical characteristics of the gas pumped through the underground pipeline was investigated. This was done because there are no scientifically sound recommendations for the optimal gas temperature after coolers at the compressor station. The presence of the site of inversion of heat exchange between gas and soil – a change in the direction of heat exchange along the length of the gas pipeline was revealed. It was proved that the air temperature above the soil surface should be substituted into the formula for calculating the change in gas temperature along the length of the pipeline between compressor stations. This made it possible to determine quantitative changes in the thermophysical and hydraulic characteristics of the gas along the pipe length, in particular, the change in density, viscosity, heat capacity, flow regime. It is shown that the change in air temperature during the year leads to a change in the gas pressure at the end of the gas pipeline section up to 0.15 MPa. A change in air temperature by 10 °С leads to a change in gas temperature by approximately 5 °С. Analytical studies made it possible to develop practical recommendations for the power-saving operation of air coolers at compressor stations. It was determined that the optimum gas temperature at the cooler outlet will be the temperature at which the heat exchange inversion point along the length of the gas pipeline coincides with the location of the subsequent station. It is shown how to control gas cooling in air coolers. In particular, by shutting down one of several operating devices and changing the speed of the fan drive. The developed recommendations will make it possible to quickly regulate the temperature mode of the underground gas pipeline operation at optimal power consumption for the operation of the gas cooling system after gas compression

Experimental Investigation of Oil/Water Emulsion Rheology in Electric Submersible Pump and its Effect on the Pump Head Performance

The presence of formation water throughout the oil well production lifetime is inevitable and consequently forming the dispersion or the emulsion due to the immiscibility of those two phases and the strong shear force acting in a rotating ESP. The formation of stable emulsion close to the inversion point will significantly increase the effective viscosity of an emulsion. This paper will present an experimental investigation of emulsion rheology inside the ESP and its effect on ESP performance under various oil viscosities and different water cuts (WC). Multi stages radial type ESP were assembled into a viscous flow loop which was initially developed by Zhang (2017). Emulsions at each WC formed from different oil viscosities, similar oil density, and surface tension. Multistage ESP was used to circulate oil/water emulsions in a close flow loop. Mass flowmeter measures both mass flow rate and fluid density, and the effective emulsion viscosity derived from an in-line pipe viscometer (PV) which locates downstream of the ESP discharge. The pressure transmitter is occupied in each pump stage to measure the pressure increment. The experiment results present in terms of pump boosting pressure at each water cut and the flow rate delivered by the pump. A Single-phase oil experiment was run at a different temperature to validate the accuracy of the PV. The data discrepancy of PV's viscosity and rotational viscometer is ±6%. The experiment results captured the emulsion's effective viscosity trend as a function of WC. A significant increase of effective viscosity close to the inversion point was observed, and it occurs due to a higher number of water droplets and hydrogen bonds which lead to an increase in hydrodynamic forces thus generating a tight emulsion. The experiment results reveal that a higher oil viscosity 70 cp reaches an inversion point at 30% - 35% WC. Meanwhile, for lower oil viscosity 45 cp reaches the inversion point at 35% - 40% WC since the turbulence increases with the decrease of oil viscosity. The increasing of effective viscosity in the water-oil emulsion induces higher pressure loss in the pump due to high friction loss, and it deteriorates the pump head. Nevertheless, as the WC increases further, the pump head will advance close to the single-phase water performance since the water turns as the continuous phase. Eventually, we can observe a prudent relationship in the pump performance in the change of emulsions effective viscosity as a function of WC. The inversion point phenomena occur at a different range of WC for different oil viscosity. Therefore, it is vital to set the possible range of operational conditions away from the inversion point. A better understanding of these aforementioned issues will lead to an accurate ESP design for optimum well performance.

Substantiating the removal of fat in the technology of obtaining wheat germ and devising technology for making cookies containing it

This paper reports the results of studying the effect of fat removal from wheat germ on its functional-technological properties, as well as its commercial potential, using the technology of butter biscuits as an example. The expediency of large-scale application of fat-free germ has been established for resolving two tasks at the same time: the introduction of the concept of lean manufacturing provided the germ utilization is scientifically justified, that is, creating value without losses. It has been noted that flour confectionery technology has prospects for the introduction of fat-free wheat germ. It has been shown that although wheat germ has a unique chemical composition, it contains much fat, which contributes to the processes of oxidation and rancidity. It is the lack of a scientific base on the influence of the fat removal process on the functional-technological properties of fat-free wheat germ that is a deterrent for its application in the food industry. The paper gives the results from studying the functional-technological properties of wheat germ from which fat was removed with freon-12. The solubility of proteins of fat-free wheat germ depending on the pH has been investigated; it was determined that the conditions for pronounced solubility were created at pH 9. It has been determined that NaCl at a concentration of 1...5 % does not affect the amount of dissolved protein. The results from investigating the surface tension of wheat germ protein solutions and fat-free wheat germ depending on the medium pH are presented. The dependence of values of the surface activity of wheat germ protein solutions on pH has been established. The dependence of the phase inversion point on the concentration of wheat germ and fat-free wheat germ has been investigated. It was determined that the emulsifying ability increases with an increase in the concentration of the suspension to 10 %. A technological scheme for making butter biscuits with the use of fat-free wheat germ has been devised.

INVERSION POINT OF EMULSIONS AS A MECHANISM OF HEAD LOSS REDUCTION IN ONSHORE PIPELINE HEAVY OIL FLOW

This work addresses the transportation of viscous crude oil as concentrated oil-in-water (O/W) emulsions flowing in a partially submerged onshore pipeline. The main goal of this study is to analyze the effects of inversion point of the water-in-oil emulsion in the pressure drop with the aid of Pipesim® software. Pressure drop is determined by applying the Dukler correlation (Taitel and Dukler, 1976) to represent dead oil viscosity as a function of temperature, and API density using the Hossain correlation (Hossain et al., 2005). The Brinkman model (Brinkman, 1952) is applied to calculate the viscosity of the emulsion, with the Brauner and Ullmann (2002) equation for the water cut off method (inversion point). The pipeline, of 3,600 m and 4 inches in diameter, transports the oil and consists of three sections. The first and third sections are above ground and are in contact with the external environment. The intermediate section is sitting on the river bed and is the critical part of the pipeline, once high heat losses are observed. The results of this 1D and non-isothermal problem show that water cuts of 5 and 6%, for low heat exchange and high heat exchange, respectively, make it possible to transport the oil, as an oil-in-water emulsion, through the entire extension of the pipeline. However, a water cut of 10% creates a high-pressure drop in the system, assuring the movement of the fluid in long sections without compromising the system operation. The use of isolation influences the temperature gradient but doesn’t have a high influence on pressure gradient compared to emulsions.

Sleep EEG microstructure in children and adolescents with attention deficit hyperactivity disorder: a systematic review and meta-analysis

Attention deficit hyperactivity disorder (ADHD) is commonly associated with sleep problems, possibly due to shared pathophysiology. Microstructural sleep electroencephalographic (EEG) alterations may likely represent markers of disordered cortical maturation in ADHD, although literature data are still conflicting, deserving further assessment. After having systematically reviewed the literature, we included 11 studies from 598 abstracts, and assessed 23 parameters of cyclic alternating pattern (CAP), four parameters of sleep EEG power and one parameter of sleep graphoelements through 29 meta-analyses and, when possible, univariate meta-regressions. Slow wave activity (SWA) in ADHD was significantly higher in early childhood and lower in late childhood/adolescence compared to controls, with an inversion point at 10 years. Total CAP rate and CAP A1 index in non-rapid eye movement (NREM) stage 2 sleep, and CAP A1 rate in NREM sleep were significantly lower in ADHD patients than controls. SWA and CAP A1 changes are therefore possible markers of altered cortical maturation in ADHD, consistently with the neuropsychological deficits characterizing the disorder, likely fostering earlier detection of at-risk/milder conditions, and more tailored therapeutic interventions.

Water resistance of structured sand-sodium-silicate mixtures

Purpose. To establish regularities of changes in sand-sodium-silicate mixtures (SSSM) relative water resistance, structured by steam-microwave solidification method (SMS), on their structuring parameters and sodium silicate solute (SSS) dissolution conditions. Methodology. Technical purity water, SSS with 2.83.0 silicate modulus, quartz sand with 0.23 mm average particle size were used in this work. Studies were carried out on quartz sand samples, which were preliminarily cladded with 0.52.5% (by weight) SSS and structured by SMS method. The fracture time of structured mixtures was evaluated on cubic specimens with 20 mm rib length, which were immersed in water at different temperatures. Findings. Changes in SSSM water resistance in water regularities depending on their manufacturing, use and storage conditions were established. Recommendations for SSSM rods removal from castings in water were developed. Originality. For the first time, it has been established that relative water resistance of the SSSM structured by SMS method decreases along with increase in water temperature in which it is destroyed. Depending on SSS mass used for quartz sand cladding in range 0.52.5%, water resistance dependence on treatment in steam-microwave environment with 27 minutes running time acquires an inversion character with inversion point `3.1 minutes into the processing. For the first time, it has been discovered that in boiling water the relative water resistance of SSSM, structured by SMS-process and having preheating, monotonically increases with preheating temperature rising from 100 to 600 , sharply increases when heated to 600700 and practically becomes absolute after preliminarily preheating to higher temperatures. Practical value. Research results will be useful in concepts of processes accompanying destruction of structured sands with water-soluble binders expanding, as well as in technologies and equipment development designed for SSS rods and mold rests removing from castings.