Mathematical Model of Hydraulic Fracturing of a Bed

© 2016, Springer Science+Business Media New York.A study has been made of the problem on the process of formation of a zone of higher-than-average permeability with a moving boundary in an initially low-permeability porous medium (problem on hydraulic fracturing of a bed) in a three-dimensional formulation. A characteristic feature of the three-dimensional problem was the taking into account the existence of two zones (zone with a regular permeability and the destruction zone) in the porous medium, whose contact region was determined using the condition of mass balance on the moving boundary. Special features fundamental to the process of mass transfer in such filtration-inhomogeneous porous media have been revealed and analyzed

Illitization of smectite as biomineralogical process

The analyzed data of 3D structure investigation for the most low-temperature illite indicate that in smectite illitization at least two mechanisms can be involved, from which one is associated with biota activity and doesn't require temperature increasing. In this case in the somewhat later initiated 'dissolution-reprecipitation' process involved are as smectite packages as well secondary mica packages, this being reflected in the reaction kinetics and its products structure

Interstratified illite-smectite phases: formation mechanisms and practical applications

© 2018 Secondary micas after smectite, including mix illite-smectite phases, can form in sediments by three mechanisms, each being specific to particular environments. As the process develops, the newly formed phases undergo structure ordering. Two mechanisms involve transformation of 2:1 mixed-layer structures, and the third is the growth of screw dislocations, with formation of ordered mix phases having a Reichweite parameter of R = 1 or R = 2. We propose methods for identifying such phases when they are present in small amounts or when their XRD patterns lack well-pronounced superperiodic reflections, as well as mathematical formalism for illitization modeling. The theoretical issues are illustrated with field examples, and the illitization mechanisms are discussed in terms of their possible practical applications

Mass transfer in aggregated porous media with nonlinear compressibility

The problem of the squeezing out of a solution from aggregates in a porous medium has been considered and investigated. A specific feature of the problem lies in taking account of the existence of two compaction zones in deforming aggregates of a porous medium. Features essential to mass transfer in a deformable aggregated porous medium have been determined and analyzed. © 2008 Springer Science+Business Media, Inc

Changes in the structures of mixed-layer illite-smectite during flooding of terrigenous oil reservoirs

A difference-spectrum method is proposed for the qualitative assessment of changes of illite-smectite structures accompanying the flooding of oil reservoirs. The method permits one to get an open system and reduce the application of procedures based on Markov's chain formalism. A computer simulation is made to obtain spectra by subtracting the spectrum of an ethylene glycol-saturated sample from the spectrum of an air-dried preparation throughout the entire range of concentrations of illite and smectite components with a short-range order factor R = 0 or R = 3.It has been established that only in the presence of filtration are the maximum and minimum of the spectra in the range of 12.5-9.4 A complicated by a number of local extrema, whose position is specified by the structure of intermediate phases. The flooding process first involves mixed-layer phases with R = 0, leading to a partial segregation of the structures into phase with one and two networks of interlayer H2O. When the secondary mica particles break, phases with R = 3 appear along the boundaries of nanoblocks, first only with 1 H2O and then only with 2 H2O in labile interspaces. Their coexistence with the phases R = 0 in the sample proves the existence of percolation effects due to two-phase filtration in the porous medium. The fully flooded reservoir is always dominated by a mechanical mixture of illite-smectite phases of different nature with R = 0 and with different ratios of components. Transformation of mica that can drastically reduce oil production begins long before the appearance of flooding zones, which are revealed by standard logging methods. © 2014

Клапаносохраняющее протезирование восходящей аорты при аномальном расположении огибающей коронарной артерии

Highlights. The combination of congenital aortic valve insufficiency and abnormal coronary artery discharge is rare. Taking into account the fact that coronary angiography is not indicated for young patients, there may be a risk of injury to the coronary artery during the correction of aortic malformation. The published case indicates the need for routine coronary angiography for all patients, regardless of their age, who are going to have aortic valve surgery.Background. Anomalous origin from right sinus and pathway of circumflex coronary artery can complicate aortic valve and root procedures. Computed tomography scan with contrast and selective angiography help to recognize the malformation and protect circumflex artery. Herein we present the case of valve sparing root replacement in patient with bicuspid regurgitant aortic valve and anomalous origin of circumflex artery.Основные положения. Сочетание врожденной недостаточности аортального клапана и аномального отхождения коронарных артерий встречается редко. С учетом того что молодым пациентам коронарография не показана, возможен риск травмы коронарной артерии при коррекции аортального порока. Публикуемый случай свидетельствует о необходимости рутинного выполнения коронарографии всем больным, которым планируется пластика аортального клапана, независимо от возраста.Актуальность Аномалия в виде отхождения огибающей артерии от правого синуса может осложнить выполнение операций на аортальном клапане и корне аорты. Компьютерная томография с контрастированием позволяет выявить аномалию и сделать безопасным клапаносохраняющее протезирование восходящей аорты с пластикой врожденного двустворчатого аортального клапана. В статье представлен случай ремоделирования врожденного двустворчатого аортального клапана при аномальном расположении огибающей коронарной артерии

СИМУЛЬТАННАЯ ОПЕРАЦИЯ У ПАЦИЕНТКИ С ЛЕЙОМИОМАТОЗОМ ПРАВОГО ЯИЧНИКА С ИНТРАКАРДИАЛЬНЫМ РАСПРОСТРАНЕНИЕМ: КЛИНИЧЕСКИЙ СЛУЧАЙ

HighlightsIntravascular leiomyoma with heart extension is a rare occurring condition. According to the available data, the number of cases does not exceed 30 despite many years of studies. Often cardiac hospitals cannot establish the clinical picture, so the surgeon removes only cardiac tumors, which inevitably leads to the recurrence of the tumor after a few months. AbstractLeiomyomatosis is an extremely rare disease that occurs in women of childbearing age. The development of the malignant tumor is preceded by the removal of the uterine fibroids or hysterectomy. Radical surgery guarantees the complete absence of relapses, while partial removal leads to relapses in a third of cases. We performed a reoperation on a 35-year-old patient who underwent partial removal of leiomyoma in the right atrium but 3 months later had a tumor causing severe obstruction of the right heart.Основные положенияИнтравенозная опухолевая инвазия лейомиомой, достигающей сердца, встречается редко. По данным литературы, количество случаев составляет не более 30 за долгие годы наблюдений. Зачастую диагностика в кардиостационарах не позволяет определить полную картину, поэтому хирург, как правило, удаляет лишь кардиальную часть опухоли, что неминуемо ведет к возврату опухолевой инвазии спустя несколько месяцев. АбстрактЛейомиоматоз – крайне редкое заболевание, встречаемое у женщин детородного возраста. Как правило, развитию опухоли предшествуют удаление миомы матки или гистерэктомия. Радикальная операция гарантирует полное отсутствие рецидивов, в то время как частичное удаление приводит к рецидивам в трети случаев. Нами выполнено повторное вмешательство у пациентки 35 лет, которая перенесла операцию в условиях искусственного кровообращения в объеме частичного удаления лейомиомы из правого предсердия, а спустя 3 мес. возник рецидив опухоли с признаками тяжелой обструкции правых отделов сердца

Interstratified illite-smectite phases: formation mechanisms and practical applications

© 2018 Secondary micas after smectite, including mix illite-smectite phases, can form in sediments by three mechanisms, each being specific to particular environments. As the process develops, the newly formed phases undergo structure ordering. Two mechanisms involve transformation of 2:1 mixed-layer structures, and the third is the growth of screw dislocations, with formation of ordered mix phases having a Reichweite parameter of R = 1 or R = 2. We propose methods for identifying such phases when they are present in small amounts or when their XRD patterns lack well-pronounced superperiodic reflections, as well as mathematical formalism for illitization modeling. The theoretical issues are illustrated with field examples, and the illitization mechanisms are discussed in terms of their possible practical applications

Low-temperature smectite illitization as a biomineral process

This paper studies the low-temperature illitization of smectite in arid basins, where fresh sediments underwent drastic changes in redox potential. We examined Upper Permian sediments from Tatarstan and the Komi Republic, as well as Lower Triassic and Upper Jurassic sediments from the Moscow syneclise (the upper Volga region. The data obtained indicate that smectite illitization can involve at least two different mechanisms, one of which is related to biota activity and does not require temperature increase. The later dissolution-reprecipitation involves both semectite and secondary mica sheets, which affect both the kinetics of the reaction and the structure of its products. Copyright © 2005 by Pleiades Publishing, Inc

Low-temperature smectite illitization as a biomineral process

This paper studies the low-temperature illitization of smectite in arid basins, where fresh sediments underwent drastic changes in redox potential. We examined Upper Permian sediments from Tatarstan and the Komi Republic, as well as Lower Triassic and Upper Jurassic sediments from the Moscow syneclise (the upper Volga region. The data obtained indicate that smectite illitization can involve at least two different mechanisms, one of which is related to biota activity and does not require temperature increase. The later dissolution-reprecipitation involves both semectite and secondary mica sheets, which affect both the kinetics of the reaction and the structure of its products. Copyright © 2005 by Pleiades Publishing, Inc