Перегляд за Автор "Kravchenko, Oleg"
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Документ Developing Structural Methods For Solving Boundary-Value Problems In Non-Smooth Boundary Domains(NTU "KhPI", 2016) Baranov, Igor; Kravchenko, Oleg; Suvorova, IrynaThe paper presents the development of structural methods for solving boundary-value problems in complexshape domains to enhance calculation accuracy in the neighbourhood of angular points in the boundary-value problems solution domain. Structural methods allow building bases for solving mathematical physics boundary-value problems, which accurately account for the boundary conditions and geometric information on the domain form. These methods are based on using the mathematical tools of the theory of R-functions. They can dramatically extend the potentialities of variation methods when solving mathematical physics boundary-value problems in complexshape domains with different boundary conditions. The most common systems of R-operations used in practice are normalised; however, they are not smooth in point (0,0), and all smooth R-operations are not normalised. The paper presents the results of investigating the behaviour of smooth functions up to the domain boundary, which satisfy uniform Dirichlet and Neumann conditions, and the condition at which the function proper and its derivatives over the normal to a definite order are equal to zero. New approaches are offered to build basis functions that are smooth up to the non-smooth domain boundary and which meet the above-mentioned boundary conditions. The suggested new system of asymptotically normalised R-operations whose functions belong to the given smoothness class can be used to build smooth basis functions that satisfy certain boundary conditions. The approaches developed were tested for model problems, some of which were used for problems in modelling hydrodynamic fields in complex-shape domains.Документ Improvement of technological-mathematical model for the medium-term prediction of the work of a gas condensate field(Технологический Центр, 2016) Kutia, Mykhailo; Fyk, M. I.; Kravchenko, Oleg; Palis, Stefan; Fyk, I.Authors proposed analytical and algorithmic additions to the mathematical model of the prediction of the work of a gascondensate field in the gas regime. The developed technique of improved calculations of the gasdynamic parameters was verified by the actual history of a number of real fields in Ukraine. It demonstrated good results by accuracy in the course of mediumterm prediction, which is important for estimating the efficiency of the measures for the intensification of well production. The new analytical construction of the systems of equations of the planeradial inflow of gas to the well bottom and transport of gas by the vertical column allowed us to make the algorithm of iterative calculations more universal. The universality consists, in particular, in the possibility to predict the results of thermobaric changes in the gas flow and changes in the design parameters of a well after technological measures for the intensification of well production. The unique difference is the possibility of rapid evaluation of the prediction of intensification of a well with the interference into both the productive layer and the downhole equipment. Authors emphasized the need for a similar further improvement of the technologicalmathematical model taking into account the new technologies of intensification, including innovative technological schemes of constructing the downhole equipment, equipment for the column of wells, wellhead equipment, multibottom and multirow systems of extraction, extraction of gas with injection into the layer of special chemical agents. The certain properties of the adaption correction of parameters made it possible to use the program realization of the developed technologicalmathematical model at the UkrainianSwedish gasextraction company TOV "Karpatygaz".