Changes in composition and pore space of sand rocks in the oil water contact zone (section YU[1] {3-4}, Klyuchevskaya area, Tomsk region)

Abstract

The article provides an analysis of specific features in changes of rocks in the oil water contact zone. The object of study is the formation YU[1] {3-4} (J[3]o[1]) of Klyuchevskaya oil deposit (West Siberian oil-gas province, Tomsk region). The research data allow the authors to determine vertical zoning of the surface structure and identify the following zones: oil saturation (weak alteration), bitumen-content dissolution, non-bitumen-content dissolution, cementation, including rocks not affected by hydrocarbon deposit. The rocks under investigation are characterized by different changes in composition, pore space, as well as reservoir filtration and volumetric parameters. Detection of irregularity in distribution of void- pore space in oil-water contact zones is of great practical importance. It helps to avoid the errors in differential pressure drawdown and explain the origin of low-resistivity collectors.