ANALYTICAL LINKS BETWEEN POROSITY AND PERMEABILITY CORRELATIONS OF PRODUCTIVE STRATA OF WESTERN SIBERIA BASED ON A GENERALIZED MATHEMATICAL MODEL OF CAPILLARY CURVES

Abstract

Relevance. Analytical relationships between the reservoir properties of Western Siberia deposits make it possible to estimate permeability and potential well production rates. Obtaining such multidimensional relationships at the initial stage of development is an important and urgent task. Multidimensional relations between reservoir parameters, proposed by different researchers, require selection and adaptation to a specific object. However, the analytical relationships proposed in this work are obtained basing on the analysis of the capillary pressure curves behavior of a reservoir. In this case, the relation automatically adapts to a specific object and is optimal in structure and character. The aim of the research is to obtain analytical expressions for multivariate associations between the filtration and capacity properties of reservoir rocks based on the analysis and generalization of core sample studies resulting from the capillarimetric studies. The obtained dependencies should provide an estimate with sufficient for practical purposes accuracy of the absolute permeability of the formation and the potential flow rate of the well based on the known residual water saturation and porosity of the formation values according to the production geophysics data. Facilities: productive strata of the Triassic, Jurassic and Lower Cretaceous ages of the Las-Egan and Povkhov oil fields. Methods: statistical processing of the core samples data from a number of productive formations basing on their capillarimetric studies. Results. On the basis of a comprehensive analysis of the generalized mathematical model of capillary curves, a technique has been developed for obtaining analytical expressions for multidimensional relationships between porosity and permeability correlations of Western Siberia reservoirs. The paper presents analytical expressions, as well as graphs of relationships between the porosity and permeability correlations for the Las-Egan and Povkhov fields, which make it possible to estimate the absolute permeability of productive formations from the known porosity and residual water saturation values. The proposed method allows obtaining multidimensional relationships for any productive formation in the conditions of Western Siberia; it is shown in the work that in hydrophilic reservoirs there is the closest relationship between the porosity and permeability properties; the reason for the close relationship between the absolute permeability of productive formations in Western Siberia and the residual water saturation of the reservoir has been identified.

Keywords

• capillarimetry
• permeability
• porosity
• residual water saturation
• structure and nature of the bond