Study of the Influence of Well Operation Parameters of a Carbonate Reservoir Oil Formation on the Coefficient of Productivity Using Statistical Methods of Analysis

Well productivity index is one of the most important indicators for the development of carbonate reservoirs of oil fields, control and maintenance of high values of which determines the levels of hydrocarbon production. Determination of the complex influence of geological and technological factors on production capabilities of wells remains an actual direction of research in the field of oil producing. The present paper is devoted to improving the efficiency of production wells in a carbonate reservoir oil deposit based on the results of evaluation and consideration of the relationship between the productivity index and geological and field parameters such as reservoir pressure, bottomhole pressure, skin-factor, gas-oil ratio, water cut, using statistical methods of analysis. At the stage of preparation of initial data the materials of hydrodynamic and production-geophysical studies performed on the wells during the whole period of development of oil reservoir of one of the fields of Perm region were involved. The analysis of the obtained data sample with the use of statistical methods allowed us to study the relationships between the specific well productivity index and the considered geological and production parameters. Multivariate statistical models were developed using stepby-step regression analysis, collectively demonstrating the predominant influence of bottomhole pressure, reservoir pressure and water cut on the specific well productivity index based on the frequencies of occurrence of parameters and the order of their inclusion in the model. The study of the dynamics of changes in the accumulated multiple correlation coefficient during the development of statistical models allowed us to identify the ranges (areas) of change in the values of the specific well productivity index, which are characterized by individual correlations with geological and production parameters described by the corresponding mathematical dependencies. The developed models are characterized by high quality, which is confirmed by their statistical evaluations when comparing forecast and factual values of specific well productivity index. The criteria of applicability of models for conditions of carbonate reservoirs of oil fields are formed. The results of the study can be used for justification and regulation of technological modes of well operation, planning programs of optimization measures.

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