Perm Journal of Petroleum and Mining Engineering

Both fields considered in the study belong to the class of long-term fields that are in the final stage of development. Both fields have a tectonically complex structure. Although they have been in development since the last century, they have significant oil reserves. Therefore, the structural-tectonic structure of fields, lithofacies composition, balance and recoverable reserves, and development parameters are of great importance. Although the fields are separated from each other by conditional faults, they are very diverse from the structural and tectonic point of view. The fields of the Darwin Bank and Pirallahi Island were poorly studied from the lithofacies point of view. That is why the study of lithofacies characteristics is of particular interest. Therefore, the goal was set to determine the lithofacies of these deposits and to compare them for the first time. The facies types of deposits of the Kirmakinskaya suite (KS), Podkirmakinskaya suite (PS), Kalinskaya suite (KaS) were studied, lithofacies characteristics in the areal and vertical directions were determined, three-dimensional models were compiled and compared. As a result, the lithofacies characteristics of both fields were mutually tracked in all directions and changes were detected. It was established that the main cause of lithofacies diversity was different paleogeographic conditions, despite the proximity of fields. Thus, in the Darwin Bank field, the KS, PS, and KaS horizons, respectively, wedged from the arch to the wings. At the Pirallahi field, KaS wedged into the southern part. This wedging out sequence increased the likelihood of non-anticlinal traps forming at these locations and created a trap for hydrocarbon accumulation. The PS formation in the Darwin Bank field was mostly composed of sands, but in the Pirallahi field the lower part of this formation was composed of shale and the upper part was composed of sands. In these two deposits, the physical and geographical conditions during the KS period were different, and different lithofacies were formed. The collected materials, the research work carried out on them and the results obtained were of great importance in the effective exploitation of these fields, in the drilling of new wells and, most importantly, in the search and exploration of new oil-bearing zones.

The high geological knowledge of the south of the Perm Krai makes it possible to collect a large amount of data to determine the oil and gas potential of the structures. The main criteria in the distribution of oil and gas content are the processes of hydrocarbon generation, accumulation, as well as the safety of hydrocarbon deposits from physical and chemical destruction. Data on geochemical studies of the oil and gas source suite (Upper Devonian Semiluk deposits) were used as criteria for the generation of hydrocarbons to assess the generation potential of the deposits. Based on the conducted seismic surveys, local structures were identified in the Visean complex of deposits. The surfaces of the regional, zonal and local components were calculated, the average values of the structural parameters were obtained to assess the influence of the accumulation criteria. Hydrogeological parameters were used as criteria for the safety of hydrocarbon deposits. To predict the oil and gas potential of the structures, multilevel probabilistic models were used. At the first level, individual statistical models were calculated for each of the parameters used, as well as complex probabilistic parameters separately for each group of criteria. At the second level, complex models were calculated taking into account all available information on the generation, accumulation and preservation of hydrocarbon deposits for the entire study area. A regression analysis was carried out with a stepwise increase in the sample of initial data. This analysis made it possible to evaluate the influence of each individual group of criteria on the saturation of hydrocarbon structures. At the third level, the calculated models were differentiated by individual large tectonic elements that are part of the study area. The constructed models of the 3rd level proved that in the territory of the south of the Perm Krai, the forecast of the oil and gas potential of local structures should be carried out separately for tectonic elements. Based on the results of the oil and gas potential forecast, 15 structures potentially saturated with hydrocarbons and 80 potentially empty structures were identified.

A methodical approach to the selection of candidate wells for measures to limit water inflow is presented, considered on the example of the Carboniferous deposit of the Vozeyskoye field in the Komi Republic. To determine the list of parameters that affect the effectiveness of measures to limit water inflow, an assessment was carried out using the Student's t-criterion: the average values of geological and technological parameters for classes of effective and inefficient measures obtained from field data were analyzed. Among the analyzed parameters, the statistically significant values were the values of permeability, porosity, net-to-gross ratio, thickness of the water inflow interval, determined by the results of flow metric studies, current reservoir pressure and fluid flow rate before well interventions. With the help of discriminant analysis, candidate wells of the Carboniferous deposit of the Vozeyskoye field were assigned to the groups of effective or inefficient operations based on a set of statistically significant geological and technological parameters. Three wells of the Vozeyskoye field have been identified for pilot work to limit water inflow, which belong to an area with a sufficient amount of residual recoverable reserves. In order to exclude unfavorable conditions for the use of water inflow limitation technologies, sources of flooding in candidate wells were identified. To increase the measures success, it is necessary to exclude from consideration wells, in which excess water flows through cracks and faults. To this end, by calculating the Spearman correlation coefficients, it was found that the hydrodynamic connection between the three candidate wells and the injection well affecting them is characterized as weak, moderate and medium, which excludes the flow of excess water through fractures.

A study of non-stationary air distribution that occurs in a skip shaft with rope reinforcement when two lifting vessels move along it was made. The theoretical analysis of air distribution was carried out using numerical simulation of an unsteady turbulent air flow in the shaft section using the Ansys Fluent software package. To describe the movement of skips, the dynamic grid approach was used, based on the deformation and rebuilding of internal grid cells during the calculation process. Based on the calculated non-stationary distribution of aerodynamic parameters near the moving skips, the total aerodynamic forces acting on the skips were calculated. They were used further to analyze the horizontal vibrations of the skips, taking into account the restrictions imposed by the lifting, balancing and guide ropes. Within the framework of the accepted model simplifications, it was obtained that the maximum values of the aerodynamic forces acting on the skips were observed for the time interval corresponding to the passage of two skips next to each other, in this case the section of the mine shaft overlapped to the maximum. A short-term increase in the aerodynamic force acting on the skip during this period of time led to the appearance of skip oscillations in the horizontal plane. It was shown that the maximum peak value of the horizontal aerodynamic force component significantly depended on the allowance for the movement of skips. This indicated that the analysis of skip oscillations in the wellbore under the assumption of instantaneously resting skips was incorrect. Further, based on the calculated aerodynamic loads on the skips in the course of a series of numerical experiments, the maximum horizontal displacements of each of the skips were determined as a function of the air velocity in the shaft. On the basis of the displacements obtained, approximating dependences for the maximum displacements of the skip were constructed depending on its mass and the average air velocity in the shaft.