The paper considers two fields characterized by high content of asphalt-resin-paraffin deposits, low permeability and high oil saturation. Carbonate fields are the primary targets for geological exploration and account for the majority of incremental oil and gas reserves. Carbonate reservoir development has been widely practiced in Tatarstan. To date, TATNEFT PJSC has set an objective to stabilize commercial oil production using chemical enhanced oil recovery methods in such fields. Improvement of oil field production performance entails application of controlled matrix and deep selective acidizing of carbonate reservoirs using acid compositions of different purposes and principles of action. However, field development is challenging because low-permeability rock matrix does not allow achieving any significant oil inflow. Productivity results predominantly from oil inflow through natural and induced fractures. In such conditions, thermo-foam acid treatment of bottomhole formation zone offers one of the promising solutions to improvement of well productivity. The authors considered a number of thermo-foam-acid compositions, evaluated their applicability and performance in producing wells of Novo-Yelkhovskoye and Aksubayevo-Mokshinskoye fields. For selection of appropriate acid composition, physical modeling of bottomhole treatment process was performed to simulate two typical injection designs: simultaneous and sequential injection of components. Created pore channels were evaluated based on reservoir properties and using 3D computer tomography methods.
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