Increase in Intake Capacity by Dynamic Operation of Injection Wells

The method of pumping water to compensate for fluid withdrawals from an oil formation in order to maintain formation pressure has long established itself as an effective technology and is widely used at oil and gas fields. At the same time, field operator is often faced with the problem of reduction in the intake capacity of injection wells, which may be caused by various complications arising in the near-wellbore area due to a violation of water treatment technology or other factors. This problem is typical for reservoirs with low permeability values, which leads to a decrease in the performance indicators of the formation pressure maintenance system. In order to counter contamination of the bottomhole zone of the well, as a rule, injection of specialized acid compositions for the purpose of cleaning is used. To increase the effectiveness of this procedure, the authors of the article propose to discharge the injection well at the maximum permissible speeds. This event will allow primary cleaning of the bottomhole zone of the formation from moving particles clogging the pore space, and reduce formation pressure in the vicinity of the injection well, which will subsequently improve the intake capacity of the well during treatment with acid compositions. The decrease in formation pressure in the bottomhole zone of the well also has a positive effect on the radius of acid penetration into the formation. The proposed approach has been successfully tested on a number of injection wells at one of «Gazprom Neft» enterprises. The results of pilot operations showed an increase in the quality of cleaning the bottomhole zone of the formation and an increase in the intake capacity of injection wells with subsequent preservation of intake dynamics

Electromagnetic response of the three-layer construction on the basis of barium hexaferrite and a foam glass

This paper contains results of study of the frequency dependence of reflection coefficient of the ceramic surface coated with the construction consisting of following layers: metal, composite on the basis of ferrite with hexagonal structure, and foam glass. It is shown that foam glass layer reduces significantly the reflecting characteristics of the construction

Radiation-thermal synthesis of W-type hexaferrites

The results of investigations of the phase composition, structural parameters, static and dynamic magnetic properties of BaCo0.7Zn1.3Fe16O27 hexaferrites obtained by the method of self-propagation high-temperature synthesis in combination with mechanochemical activation and radiation-thermal post-sintering are presented. The prospects of the proposed energy-saving approach for the production of ferrite ceramics with a hexagonal structure is shown

Electromagnetic properties of LaCa[3]Fe[5]O[12] in the microwave range

The X-ray diffraction analysis of the LaCa[3]Fe[5]O[12] ferrite (lanthanum ferrite) prepared through high-temperature synthesis via ceramic technology was performed. It was found that ferrites belong to tetragonal system. The electromagnetic response from a flat layer of the composite based on this material under electromagnetic radiation in the frequency range of 0.01-18 GHz was investigated. It is shown that the developed material effectively interacts with electromagnetic radiation. The interaction effectiveness is directly proportional to ferrite concentration. Increased concentration of ferrite leads to growth of the reflection coefficient due to high conductivity of the material and visible decrease in the transmission coefficient in the frequency range of 4-14 GHz

Carbon Supported Polyaniline as Anode Catalyst: Pathway to Platinum-Free Fuel Cells

The effectiveness of carbon supported polyaniline as anode catalyst in a fuel cell (FC) with direct formic acid electrooxidation is experimentally demonstrated. A prototype FC with such a platinum-free composite anode exhibited a maximum room-temperature specific power of about 5 mW/cm2Comment: 11 pages, 3 Postscript figures, atricle tex styl

Синтез, структура и электромагнитные свойства нанокомпозитов FeCoCu/C

FeCoCu ternary nanoparticles distributed and stabilized in the carbon matrix of FeCoCu/C metal-carbon nanocomposites have been synthesized using controlled IR pyrolysis of precursors consisting of the “polymer / iron acetylacetate / cobalt and copper acetates” type system obtained by joint dissolution of components followed by solvent removal. The effect of the synthesis temperature on the structure, composition and electromagnetic properties of the nanocomposites has been studied. By XRD was shown that the formation of the FeCoCu ternary nanoparticles occurs due to the interaction of Fe3С with the nanoparticles of the CoCu solid solution. An increase in the synthesis temperature leads to an increase in the size of the metal nanoparticles due to their agglomeration and coalescence as a result of matrix reconstruction. Furthermore, ternary alloy nanoparticles having a variable composition may form depending on the synthesis temperature and the content ratio of the metals. Raman spectroscopy has shown that the crystallinity of the carbon matrix of the nanocomposites increases with the synthesis temperature. The frequency responses of the relative permittivity and permeability of the nanocomposites have been studied at 3–13 GHz. It has been shown that a change in the content ratio of the metals noticeably increases both the dielectric and the magnetic losses. The former loss is caused by the formation of a complex nanostructure of the nanocomposite carbon matrix while the latter one originates from an increase in the size of the nanoparticles and a shift of the natural ferromagnetic resonance frequency to the low-frequency region. The reflection loss has been calculated using a standard method from the experimental data on the frequency responses of the relative permittivity and permeability. It has been shown that the frequency range and the absorption of electromagnetic waves (from –20 to –52 dB) can be controlled by varying the content ratio of the metals in the precursor. The nanocomposites obtained as a result of the experiment deliver better results in comparison with FeCo/C nanocomposites synthesized under similar conditions.Синтезированы тройные наночастицы FeCoCu, распределенные и стабилизированные в углеродной матрице металлоуглеродных нанокомпозитов FeCoCu/C. Синтез нанокомпозитов осуществлен методом контролируемого ИК-пиролиза прекурсоров типа «полимер — ацетилацетонат железа — ацетаты кобальта и меди», полученных совместным растворением компонентов с последующим удалением растворителя. Исследовано влияние температуры синтеза на структуру, состав и электромагнитные свойства нанокомпозитов. Методом рентгенофлуоресцентного анализа показано, что образование тройных наночастиц FeCoCu происходит за счет взаимодействия Fe3С с наночастицами твердого раствора CoCu. С повышением температуры синтеза увеличивается размер наночастиц металлов, что обусловлено процессами их агломерации и коалесценции при перестройке матрицы. Также в зависимости от температуры синтеза и соотношения металлов могут образовываться наночастицы тройного сплава с различным составом. Методом рамановской спектроскопии показано, что с повышением температуры синтеза степень кристалличности углеродной матрицы нанокомпозитов возрастает. Исследованы частотные зависимости относительной комплексной диэлектрической и магнитной проницаемости нанокомпозитов в диапазоне 3—13 ГГц. Показано, что изменение соотношения металлов приводит к значительному увеличению как диэлектрических, так и магнитных потерь. Первые связаны с формированием сложной наноструктуры углеродной матрицы нанокомпозита, а вторые обусловлены увеличением размера наночастиц и сдвигом частоты естественного ферромагнитного резонанса в низкочастотную область. Расчеты потерь на отражение проведены по стандартной методике на основе экспериментальных данных частотных зависимостей комплексной магнитной и диэлектрической проницаемости. Показано, что регулирование частотного диапазона и значения поглощения электромагнитных волн (от –20 до –52 дБ) может осуществляться путем изменения соотношения металлов в прекурсоре. Полученные нанокомпозиты обеспечивают более высокие результаты по сравнению с нанокомпозитами FeCo/C, полученными при аналогичных условиях

Shattered pellet injection experiments at JET in support of the ITER disruption mitigation system design

A series of experiments have been executed at JET to assess the efficacy of the newly installed shattered pellet injection (SPI) system in mitigating the effects of disruptions. Issues, important for the ITER disruption mitigation system, such as thermal load mitigation, avoidance of runaway electron (RE) formation, radiation asymmetries during thermal quench mitigation, electromagnetic load control and RE energy dissipation have been addressed over a large parameter range. The efficiency of the mitigation has been examined for the various SPI injection strategies. The paper summarises the results from these JET SPI experiments and discusses their implications for the ITER disruption mitigation scheme

New H-mode regimes with small ELMs and high thermal confinement in the Joint European Torus

New H-mode regimes with high confinement, low core impurity accumulation, and small edge-localized mode perturbations have been obtained in magnetically confined plasmas at the Joint European Torus tokamak. Such regimes are achieved by means of optimized particle fueling conditions at high input power, current, and magnetic field, which lead to a self-organized state with a strong increase in rotation and ion temperature and a decrease in the edge density. An interplay between core and edge plasma regions leads to reduced turbulence levels and outward impurity convection. These results pave the way to an attractive alternative to the standard plasmas considered for fusion energy generation in a tokamak with a metallic wall environment such as the ones expected in ITER.& nbsp;Published under an exclusive license by AIP Publishing

Overview of JET results for optimising ITER operation

The JET 2019–2020 scientific and technological programme exploited the results of years of concerted scientific and engineering work, including the ITER-like wall (ILW: Be wall and W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major neutral beam injection upgrade providing record power in 2019–2020, and tested the technical and procedural preparation for safe operation with tritium. Research along three complementary axes yielded a wealth of new results. Firstly, the JET plasma programme delivered scenarios suitable for high fusion power and alpha particle (α) physics in the coming D–T campaign (DTE2), with record sustained neutron rates, as well as plasmas for clarifying the impact of isotope mass on plasma core, edge and plasma-wall interactions, and for ITER pre-fusion power operation. The efficacy of the newly installed shattered pellet injector for mitigating disruption forces and runaway electrons was demonstrated. Secondly, research on the consequences of long-term exposure to JET-ILW plasma was completed, with emphasis on wall damage and fuel retention, and with analyses of wall materials and dust particles that will help validate assumptions and codes for design and operation of ITER and DEMO. Thirdly, the nuclear technology programme aiming to deliver maximum technological return from operations in D, T and D–T benefited from the highest D–D neutron yield in years, securing results for validating radiation transport and activation codes, and nuclear data for ITER