Numerical modeling of multiphase mass transfer processes in fractured-porous reservoirs

The paper presents an algorithm for solving the problem of the process of mass transfer of a two-phase fluid in a fractured-porous reservoir in a one-dimensional formulation. The presence of natural fractures in such reservoirs impedes various types of exploration and field development. Fractured-porous reservoirs are characterized by intense exchange fluid flow between fractures and porous blocks. Each system has its own individual set of filtration-capacity parameters, and this fact complicates the problem under consideration. To study the mass transfer of a two-phase fluid in a medium with double porosity, a four-block mathematical model with splitting by physical processes is proposed. The model is described by a system of partial differential equations. The splitting method forms two functional blocks on the water saturation and the piezoconductivity. For the numerical solution of this system, an absolutely stable implicit finite-difference scheme is constructed in the one-dimensional case. On the basis of the proposed difference scheme, pressures and saturations in the fracture system and matrix are obtained.

FEATURES OF HYDRODYNAMIC MODELING OF DEVELOPMENT OF UNDERGROUND GAS STORES IN CRACKED POROUS RESERVOIRS

При разработке подземных хранилищ газа наблюдается образование конусов подошвенной воды, что ведет к самозадавливанию скважин. Для борьбы с данным явлением необходимо определять оптимальные объемы буферного газа. В данной статье представлены результаты моделирования данной технологии в гидродинамическом симуляторе. In the development of underground gas storage facilities, the formation of cones of bottom water is observed, which leads to self-suppression of wells. To combat this phenomenon, it is necessary to determine the optimal volumes of cushion gas. This article presents the results of modeling this technology in a hydrodynamic simulator.

Solution of the Problem of Natural Gas Storages Creating in Gas Hydrate State in Porous Reservoirs

Underground gas hydrate storage of natural gas is a rather promising way of creating underground storage facilities for hydrocarbon raw materials in porous reservoirs. This paper presents a solution to the problem of the formation of CH4 hydrate in a porous medium during the injection of methane into a reservoir at a temperature lower than the initial temperature of the reservoir. Self-similar solutions of the problem in axisymmetric approximation are given, describing the pressure and temperature distribution in separate reservoir regions at the formation of gas hydrate on the frontal surface. On the basis of the method of sequential change of stationary states, an analytical solution was obtained, which allowed us to determine the position of the methane hydrate formation boundary depending on different parameters for any moment of time. The limits of the applicability of the proposed model are also given. Thus, the analysis of the calculation results showed that the constructed solution allows one to sufficiently and accurately determine the values of parameters at the frontal surface for a highly permeable medium (k0 > 10−13 m2). It was proved that in the case of a highly permeable medium, the methane hydrate formation intensity will be limited by convective heat dissipation during hydrate formation.