The article describes the first Russian experience of foamy-nitric hydraulic fracturing with proppant and acid injecting in the fourth development stage carbonate deposits of Bashneft PJSOC. Geological peculiarities and properties of oil-bearing carbonate reservoirs are given. The experience of previously tested hydraulic fracturing technologies, already implemented at Bashneft PJSOC, is reviewed. The task of justifying the main criteria for selecting the most optimal technologies of hydraulic fracturing with reference to the specific geological and physical conditions is realized. There was developed the basic principles of choosing the optimal technology for acid fracturing depending on geomechanical properties of reservoir rocks, estimated according to Acoustic Logging. To obtain the values of geomechanical characteristics of reservoirs, the authors used the methodology based on rock brittleness ratio (Poisson's ratio vs. Young's modulus). After having estimated the geomechanical properties of reservoirs we established the feasibility of applying acid fracturing with proppant in carbonate reservoirs located in the Northern part of the region. There was chosen the most optimal facilities for experimental-industrial tests aimed at fixing hydraulic fractures and increasing the effect of geological and technical measures. In the first phase we tested and further adapted hydraulic fracturing with proppant (including horizontal wells with multistage fracturing). This successful experience allowed us implementing the technology and increasing the efficiency of acid fracturing in a number of carbonate objects. In March 2016 we tested the technologies of foamy-nitric hydraulic fracturing with the injecting proppant and acid at sites with reduced formation pressure and sensitive to water. After using this technology we received an inflow with production rate of 28 t/day compared to planned value of 17.1 t/day. According to the results it was noted that the tested technology of foam-nitric acid fracturing allows continuing profitable site development where traditional simulating methods did not give the desired effect.
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