Field development. Reservoir engineering. Production
NUMERICAL STUDY OF THE INJECTION PROCESS OF CARBON DIOXIDE IN METHANEHYDRATE LAYERS TAKING INTO ACCOUNT GASES REAL PROPERTIES
Annotation. A mathematical model of the replacement of CH4 by CO2 in methane hydrate reservoir by injection of carbon dioxide, taking into account the finite length of the reservoir, the real gas properties, the effect of Joule-Thomson and adiabatic compression. The task with a moving interfacial boundary is solved numerically by the method of catching the front in the grid node. It is proved that depending on the parameters of the injected carbon dioxide and the parameters characterizing the initial state of the system, the process can occur with the formation of a hydrate of carbon dioxide, with the formation as hydrate of carbon dioxide and a mixture of methane and water. The maps of the solutions, i.e. the critical charts that determine the existence of each of the two modes of the process. It is shown that the mode of methane hydrate decomposition into gas and water (i.e. mode with two moving boundaries of phase transitions) is implemented in low-permeability porous media, as well as at high temperature and low pressure of the injected carbon dioxide. The dependence of the recovery rate of methane from the permeability and initial reservoir pressure is researched.
In article the necessity of increasing of attention from the state to questions of formation of the factors motivating subsoil users to long-term development and investigation of fields of hydrocarbonic raw materials is proved. It is pointed the need of formation of the system consistent for legislative ensuring oil production covering the whole range of organizational economic problems and relations including maintenance of resource base of the oil complex.
Deterioration of resource base in process of exhaustion of the exploited oil fields, decrease in size and quality of new geological deposits are distinguished from the main internal problems and restrictions of development of oil complex. Need of the solution of organization-legal and economical legal problems as their suspense most makes negative impact on reproduction of inventories of hydrocarbonic raw materials is emphasized. Special attention in article is paid to questions of improvement of the taxation of oil and gas production. In case of the existing tax regime the oil companies are aimed at intensive selection of oil with the minimum costs, develop, as a rule, the most profitable fields and the most productive oil-bearing layers of fields. Besides, conducting high-risk prospecting and evaluation works isn’t stimulated.
Possible measures of the state support in the sphere of business taxation of oil companies holding geological exploration works are considered, their comparative characteristic is given. Assessment of opportunities of use of a procedure for granting of privileges on profits tax within a regional component of this tax to the companies carrying out geological exploration works is given. For increase the efficiency of the similar mechanism the differentiated approach to granting a privilege on profit tax within a regional component depending on scales of activity of the organization subsoil user is offered.
Calculation of released amounts as a result of a privilege application at the rate of 2 % of taxable profit on the example of PJSC «ANC «Bashneft» is presented.
The presented option of privilege granting can be considered as the mechanism of redistribution of a mining rent in favor of the organizations investing in geological exploration and thus promoting accumulation of resource potential of regions. The possibility of simultaneous use of several instruments of stimulation, or their combination is noted.
Density and viscosity measurement is widely used in the drilling, production, processing of oil and sales of petroleum products. The article presents mathematical modeling of free damping oscillations plate in various fluids and experimental verification to confirm the adequacy of the model. As a result of the research, a mathematical relation linking free damped oscillations parameters (frequency, damping) and liquid parameters (density, viscosity) was obtained, and experimental research were performed. As a result of the experiments oscillograms of free oscillations of plate vibration in liquids with different density and viscosity were obtained, the resonator’s constants, the «attached» mass and the thickness of the layer of the «attached» liquid were calculated. Using the calculated coefficients, the density and viscosity of kerosene and acetone are determined. The achieved model allows to determine the regularities of the change of free oscillations frequency in a liquid, depending on the density, and also define the parameters of the damping plate vibrations in a viscous liquid; on the basis of experimental data, to calculate the necessary coefficients for a given resonator and subsequently use them to estimate fluids density and viscosity using oscillogram of damping oscillations.
The article discusses the effectiveness of the method to increase the productivity of wells when they are treated with aqueous solutions of binary mixtures. After injection of the solution into the formation, an exothermic reaction of interaction between the components of the binary mixture accompanied by the evolution of gases is initiated. The impact on the bottomhole zone of oil wells of heated chemical reaction products is combined and reduces to three phenomena: the warming of the rock and the oil in it; cleaning of the bottomhole zone from paraffins, resins and colmatizing sediments; expansion of natural cracks and the appearance of artificial cracks. As a result of the treatment near the well, two regions are formed: with increased conductivity and high temperature (where the viscosity of the oil decreases). The sizes of the areas may not coincide. Each region contributes to an increase in the productivity of the well. In the work by methods of mathematical and numerical modeling, the processes of thermal effect of chemical reaction products to the formation are investigated and the increase in the flow rate of the well is estimated due to the decrease in the viscosity of oil. A mathematical model of the reacting process for a binary mixture in a porous media, its filtrations and influence on a reservoir system is proposed. The numerical solution of the problem was carried out on the basis of the OpenFOAM open integrated platform. The results of numerical modeling of the reaction process of a binary mixture and the subsequent extraction of oil from a heated reservoir are presented. Estimates of the temperature increase and the size of the heating region during the exothermic chemical reaction in the pore space, as well as the expected increase in oil production and the duration of the effect were obtained. The cases of different concentration of active substances are investigated. The high economic efficiency of the method for increment well production is shown