USE OF MULTIDIMENSIONAL STATISTICAL MODELS FOR OPERATIONAL CONTROL OF RECOVERABLE RESERVES FOR THE VISEAN DEPOSITS OF THE PERM REGION
The relevance. As part of the annual geological and economic assessment of reserves in accordance with international standards, it is recommended to use analogy methods, including multidimensional statistical methods, when assessing oil recovery factors. The currently used statistical models for the deposits of the Perm region are based on the analysis of information as of 2008. Over the past decade, for the study area, there has been a massive introduction of fundamentally new reservoir development technologies, which significantly increased the development efficiency and the attainable values of the design oil recovery factors. Accordingly, in modern conditions, it is necessary to clarify the operating models for predicting oil recovery factors.The purpose of the research is updating multidimensional models for predicting oil recovery factors for the Visean oil production objects of the Perm region, taking into account modern oil field development experience.Objects: the clastic Visean oil production objects of the Perm region.Methodology. The analysis of geological and technological indicators of development was carried out, their influence on the approved values of oil recovery factor was assessed according to the current project technological documents. The method based on the Student's t-distribution, correlation analysis and multiple regression method were used as statistical ones. The analysis was carried out separately for oil deposits developed under the conditions of the reservoir pressure maintenance system and in the natural depletion mode. The results of the statistical assessment of oil recovery factors for deposits at late stages of development are compared with those approved in the project technological documents.Results. The obtained multidimensional statistical models make it possible to promptly predict oil recovery factors for deposits developed with reservoir pressure maintenance and in natural depletion mode. Forecasting models were built in two versions: based on geological and physical indicators for fields at the exploration stage (category C1+C2 reserves) and geological and technological indicators for developed fields (category A+B reserves). The convergence of the obtained models showed satisfactory results for objects at late stages. The obtained models can be used for operational control of recoverable oil reserves when designing oil field development and conducting geo- logical and economic assessment of reserves according to international standards.