Quantitative assessment of hydraulic tortuosity of oil and gas reservoirs in Western Siberia based on capillarimetric studies

Abstract

It is known that a capillary model with a given size pore channels distribution does not allow estimating the absolute reservoir permeability with sufficient accuracy. In this case, it is necessary to introduce a certain correction factor into the formula, which is called either the lithological factor or hydraulic tortuosity. The paper shows that the need for a correction factor appears mainly due to the capillary model inconsistency to the real geometry of the reservoir void space. In this regard, we propose to use the dumbbell model when calculating the absolute permeability, in which the filtering channels are represented by alternating pores and interporous narrowings. This paper presents a methodology for calculating the hydraulic tortuosity for reservoirs of Western Siberia based on the results of capillary studies, as well as based on the data from the capacitive properties study. Hydraulic tortuosity is explained by the process of expansion of current lines in the pores and their contraction in the interporous tubules of the rock. It is noted that the residual water leads to a narrowing of the pores’ open area and, accordingly, to a certain decrease in the hydraulic tortuosity.