A significant number of small oilfields on the territory of the Republic of Tatarstan are operated by small oil companies. These fields are mostly characterized by high oil viscosity and low formation pressures. Sheshmaoil Management Company LLC is a leading one among small oil companies of Tatarstan in many respects. The structure of Sheshmaoil Management Company LLC includes 7 small oil-producing companies, three of them (Sheshmaoil JSC, Ideloil JSC, Geotekh JSC) are actively engaged in R&D activities in the field of improving the oil production efficiency from wells through their evacuation. On the oilfields of Sheshmaoil JSC (Severnoye, Letneye, Novo-Sheshminskoye and Krasnooktyabrskoye fields), 19 local structures are under commercial development, the objects of which are oil deposits of carbonate sediments of the Bashkirian and Tournaisian stages, Vereiskian horizon, terrigenous sediments of the Aleksinsky and Tula-Bobrikovskiy horizons of the Early Carboniferous, Kynovskiy and Pashiyskiy horizons of the Late Devonian. 55 oil deposits confined to twelve local uplifts (Svetlogorskoye, Zagonnoye, Dachnoye, Novo-Kadeevskoye, Krasno-Klyuchevskoye, Kuteminskoye, Vostochno-Kuteminskoye, Yasakskoye, Sukhoye, Grivinskoye, Yuzhno-Ulyanovskoye, Serebryanno-Klyuchevskoye) have been identified within the area of the Dachnoye field of Ideloil JSC. Eight of them are confined to the carbonate deposits of the Vereiskian horizon, 8 — to the deposits of the Bashkirian stage, 1 deposit - to the Aleksinsky horizon, 13 deposits are confined to the deposits of the Tournaisian stage of Early Carboniferous. To terrigenous deposits of the following horizons: Tula - 4 deposits, Bobrikovskiy - 16 deposits, Kynovskiy - 5 deposits. 42 deposits of oil are under commercial development.

Hydraulic fracturing is fundamental to optimizing the development of carbonate reservoirs at fields on the western slope of the South Tatar arch in the Republic of Tatarstan. The importance of hydraulic fracturing is becoming increasingly decisive for the exploration of oil fields as the total scope of hydraulic fracturing is increasing and, consequently, the share of man-made fracturing is also increasing. The paper proposes a solution to the problem of obtaining reliable data on the nature of newly formed conducting structures and the seepage flows of formation fluids during the development of producing formations, faced by oil and gas field operators. The article also provides the analysis results of the properties of a man-made fracturing and their spatial propagation, triggered by multistage fracturing (MSHF) in horizontal well ends. The studies revealed that increased volume of proppant injection leads to an expansion of fracture's dimensions, the length being more and the height much less, while the intensity of microseismic emission is correlated with the proppant flow rate. In the process of hydraulic fracture formation, concurrent activation of the existing natural fractures occurs. Increasing the injection volume leads to greater spatial coverage of the reactivation area of existing fractures. Based on the concept of critically stressed state of the rock massif, the obtained network of natural fracturing has been schematized. The identified fractures can be grouped into fracture systems with conditional kinematics according to the Coulomb-Anderson model as reverse faults of northwest extension with the azimuth of 146.79° (326.79°), as normal faults based on azimuth of HF fractures, as strike-slip faults of northeast and west-northwest extension with azimuths of 24° (204°) and 95 (275°), respectively. The obtained results mostly confirm the common nature of the spatial variation, the causes of its occurrence, and progression of a field of fractures Besides, to increase the efficiency of well operation the technology of gas evacuation from annular space of the well and its partial utilization by means of KOGS compressor unit was applied at the wells under examination (3292 and 3294).

Enhanced recovery of residual deposits from the mature fields with steadily increasing water cut is considered one of the most important tasks in oil field development. This is particularly relevant for terrigenous deposits of minor oil fields under the third and fourth stages of development, when the water cut may grow but fail to reach the expected stabilization asymptote, thereby bringing the issue of economic feasibility of further operation into discussion. Efforts to solve these problems through the conventional techniques of cyclic injection (huff ‘n’ puff process), inflow/conformance control, filtration flow modification, and polymer flooding are generally unsuccessful. The paper reviews information on methods of steadying oil production, reducing water cut and preventing its growth, as well as on a set of measures to improve the efficiency of developing the Zarechnoye field in the Republic of Tatarstan.

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