Statistical Justification for the Formation of Skin Factor Values during Acid Treatment in Layered-Heterogeneous Bashkir Deposits of Perm Krai

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Abstract

Carbonate deposits of the Bashkirian Stage in Perm Krai are characterized by a high degree of heterogeneity, which makes it difficult to develop oil reserves evenly. Acid treatments are currently one of the most popular methods of regulating development in carbonate reservoirs. However, in conditions of layeredheterogeneous sediments the most permeable part of the section is mainly affected, while the low-permeable part of the section remains uninvolved in the development process. In this connection, it is an urgent task to predict the degree of impact of acid treatment on individual reservoir layers. The purpose of this study was to create mathematical models for predicting the skin factor of the reservoir after acid treatment. As input data we used skin factor determinations in reservoirs and geologic characteristics of these reservoirs: porosity coefficient, permeability coefficient, oil saturation coefficient and reservoir thickness. Mathematical modeling methods were used in the study: stepwise regression analysis, construction of probabilistic-statistical models. According to the results of statistical analysis it was revealed that reservoirs are divided into two classes, in which the formation of the skin factor value depends on different characteristics of the reservoir. To determine the class to which the reservoir formation belongs, univariate probabilistic-statistical models were built and subsequently combined into a single complex model. For each identified class, regression models were developed to predict the skin factor of the formation after acid treatment. The obtained mathematical models can be applied in the design of geological and technological measures, as well as to improve the accuracy of hydrodynamic modeling by taking into account the values of skin factors in the bottomhole zone in the adaptation of the model.

Keywords

stepwise regression analysisprobabilistic-statistical modelcomplex probabilityacid treatmentcarbonate reservoirskin factorporositypermeabilityoil saturation

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Article information

Published
31 October 2024
Issue date
31 October 2024
Issue
Vol. 24, No. 4 (2024)
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