Аннотация. При разработке продуктивных карбонатных коллекторов наиболее эффективным методом увеличения добычи нефти является проведение различного вида соляно-кислотных обработок (СКО) скважин, сущность проведения которых заключается в увеличении проницаемости призабойной зоны пласта (ПЗП). На промыслах западного Башкортостана интенсификация притока нефти с использованием соляно-кислотных обработок находит достаточно широкое применение. В последние годы технология проведения кислотных обработок совершенствуется. Обобщая опыт проведения и эффективность соляно-кислотных обработок скважин в нефтегазодобывающем управлении (НГДУ) «Туймазанефть» за 1971-1985 гг. эффект на одну операцию составлял в

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One of the fundamental methods of developing low-permeability reservoirs is the use of multi-stage hydraulic fracturing in horizontal wells. Decreasing wells productivity requires geological and technical measures, where one of the methods is "blind" refracturing. Often, only one "blind" hydraulic fracturing is carried out for all ports of multistage hydraulic fracturing, the possibility of carrying out two or more stages of "blind" hydraulic fracturing is considered in this article. The purpose of the article is to increase the productivity of horizontal wells with multi-stage hydraulic fracturing by the "blind" refracturing method. A one-stage and two-stage approach was implemented when planning and performing "blind" hydraulic fracturing with analysis of treatment pressures, indicating a possibility for reorientation of the fracture during the second stage in a horizontal wellbore. Based on the experience of the "blind" hydraulic fracturing performed at the Kondinskoye field, "NK "Kondaneft" JSC carried out pilot work on "blind" refracturing at four horizontal wells of the Zapadno -Erginskoye field. A geomechanical model was used, built based on well logging and core studies carried out at "RN-BashNIPIneft" LLC. The total mass of the planned proppant per well was 280-290 tons, while this tonnage was pumped in one or more stages. A one-stage "blind" refracturing approach was successfully performed in one well, two-stage hydraulic fracturing was implemented in three wells, where in one of the wells, after two stages to open ports, initial hydraulic fracturing was also carried out to the last, previously non-activated port. In the case of two-stage hydraulic fracturing, the first stage purpose was to saturate the reservoir-fracture system with the injection of a "sand plug" with a high concentration of proppant at the end of the job to isolate the initial injectivity interval, determined based on the interpretation of well logging data and analysis of the wellhead treatment pressure. The second stage purpose was the initiation and possible reorientation of the fracture in a new interval, confirmed by an increase in surface pressure during hydraulic fracturing and instantaneous shut-in pressure. This article summarizes the results and lessons learned from the pilot works carried out using the geomechanical model and well productivity assessment before and after "blind" fracturing. The analysis of surface pressure based on production data indicating fracture reorientation is presented. The recommendations and accumulated experience presented in this work should increase the effectiveness of repeated "blind" refracturing in horizontal wells with multi-stage hydraulic fracturing.

In the structure of potential oil reserves in Western Siberia, the share of hard-to-recover reserves (HRR) is growing. At the same time, a significant share of these reserves is concentrated in low-permeability reservoirs. Horizontal wells using multi-stage hydraulic fracturing are the basis of technological solutions used for cost-effective development of low-permeability reservoirs by Russian oil and gas producers [1-4]. Due to the high efficiency of the subsea development systems with MSHF, oil production from such facilities exceeds oil production from traditional reservoirs and accounts for more than 60 % of the total oil production of the Company's fields [5]. The following characteristics are identified as the key parameters of the horizontal section, the number of hydraulic fractures, as well as the specific weight of the injected proppant at the frac stage. The decisions approved as part of the design documents for the development of facilities with TPP indicate a tendency to increase the length of the horizontal hole and the number of frac operations with a decrease in the specific mass of proppant on the port. The article examines the impact of these characteristics on the technological efficiency of wells. The purpose of the work is to assess the feasibility of increasing the technological complexity of HW with multi-stage hydraulic fracturing of the MSHF formation in the form of increasing the number of stages and length of the horizontal hole, as well as the specific mass of proppantane in the example of the AS10/1 Kondinskoye field development target. Within the framework of the study, three types of HW with MSHF were identified, the technological effectiveness of which was assessed in two ways. The first method consisted in comparing the magnitudes of the dimensionless productivity coefficient Jd (d. units) of three different types of wells with a horizontal end in relation to directional wells (FWS with frac) of the environment. Taking into account the similarity of the geological conditions of the neighboring wells, this method made it possible to assess how effectively the completion of the horizontal wells under study was completed. The multiplicity assessment methodology was developed by RN-BashNIPIneft LLC [6]. The second method was to compare the ratio of dimensionless productivity factor to the specific weight of proppant Jd/Mpr _ specific of the identified types of HW with multi-stage hydraulic fracturing (MSHR). This approach made it possible to take into account the effective thickness and permeability of the formation in the well drilling zone, as well as the weight distribution of the injected proppant. The results showed that if the length of the horizontal hole is constant, an increase in the number of frac stages while reducing the proppant weight on the port is impractical. Confirmation was also obtained based on statistical data that there is a relationship between the cumulative fluid withdrawal and the weight of the injected proppant. It has been established that drilling HW with multi-stage hydraulic fracturing of the (MSHF) formation of the most common type (1000 m, 10 stages) is not optimal for the study target: for a length of 1000 m, the maximum number of stages should be limited to 7–8 units per well. Further monitoring and analysis of production wells with horizontal termination is recommended to collect more statistical data and compare them over time.