The paper considers the issue of increasing the hydraulic fracturing efficiency in a multilayer facility at the final stage of development with an uneven degree of reserves development along the section. Based on the results of the analysis, it was found that the upper layers, which have the worst filtration-reservoir properties, are less developed in comparison with the highly productive lower ones. When hydraulic fracturing was carried out in the upper formations, some of the operations had low success due to the breakthrough of hydraulic fractures into the lower depleted formations. On the basis of the revealed dependencies, the work determined the optimal specific loading of proppant per meter of effective power, depending on the geological conditions, and maps of the prospects for hydraulic fracturing are built. Keywords: oil fields development; hydraulic fracturing; hydraulic fracturing optimization; multilayer facilities.

The article presents the theoretical studies results of hydrochloric acid compositions filtration in carbonate collectors porous media saturated with two-phase formation liquid. Solution of filtration problem in the process of carbonate rock leaching with possible regulation of process by hydrocarbon solvents is considered. Numerical algorithm of acid effect on oil-saturated formation is proposed and tested, which allows to determine the following parameters of filtration flow: concentration of hydrochloric acid, distribution of water saturation, pressure and other parameters. A mathematical model of the carbonate collector dissolution process using composite solvents has been developed, which allows predicting technological indicators of acid impact efficiency.

The paper presents the possibilities of expanding production opportunities in the oil company PJSC Tatneft. For this purpose, the well No.xxx7g with an inclined pilot borehole was drilled at the Bavlinskoye oil field and oriented core samples were taken to study the lithological cross-section and the geological structure of the subsurface horizons. The horizontal wellbore itself is located in the dankovo-lebedyansky horizon, where multi-zone hydraulic fracturing was carried out through ports with packers there. The following methods will increase the share of recoverable oil reserves in the oldest oil-producing Volga region by starting the development of new productive horizons and increase the oil recovery factors for these reservoirs. The methods used in this work will reduce the unit costs of increasing oil production and achieve a cost-effective level of work on wells of this type. The work had its own peculiarities. One of the reasons for the difficulty in interpreting the hydraulic fracturing Minifrac (Meyer software package) was the rather long time of closing fractures in domanic deposits during the registration of pressure drop. In turn, during the minifrac analysis of the Nolte G Time Test graph showed that the fracture did not close, and therefore it is impossible to determine the closing pressure (the pressure gradient of the gap) with reliable accuracy. Note that when interpreting the flow test results, the best match of the experimental and calculated curves is achieved when using the model of a horizontal well operating a homogeneous reservoir. Also, the deterioration of the bottom-hole zone may be associated with a weak opening of the created fractures. Keywords: oil; well; hydraulic fracturing; unconventionals; fracture; core.

No abstract

Currently, the share of hard-to-recover oil reserves confined to carbonate reservoirs is more than 20% of the Volga-Urals hydrocarbon reserves. The use of traditional acid stimulation in conditions of a complex structure of carbonate reservoirs and low reservoir pressure is ineffective. In order to increase the efficiency of hydrochloric acid treatment, theoretical and experimental studies have been carried out aimed at increasing the efficiency of the work being carried out to stimulate the inflow to production wells that operate carbonate reservoirs. Filtration of the acid solution into low-permeability intervals of the carbonate reservoir involves the use of reverse counter-current capillary impregnation mechanisms. Analytical research methods made it possible to determine that the activation of the impregnation processes is carried out under conditions of nonstationarity of the pressure parameters of the reservoir system. Numerical modeling of the exposure process allowed to optimize the exposure parameters.