The influence of sand complexes of components of the bitumen deposit on the estimation of reserves of high viscosity oils

Abstract

In recent times there are an active investigations and exploration of natural bitumen and high-viscosity oils. Reservoirs of high-viscosity oil are characterized by high lithological and structural heterogeneity. According to knowledge of heterogeneity new tasks arise for lithological and petrophysical studies of such reservoirs: development of interpretation technique of geophysical well logging data which is suitable for investigating structures; analysis of the obtained information on the geological structure, petrophysical properties and estimation of the reserves of the investigated object based on the results of interpretation and laboratory studies of the core. The article describes the influence of sand complex types on estimation of reserves of high-viscosity oil by the example of two terrigenous uplifts of the Sheshhminskiy horizont of Ufimian stage on the south-east of the Republic of Tatarstan. The results of the research showed that the deposits of high-viscosity oil of Nizhniy-Karmal and Melnichniy uplifts have a block structure and are subdivided into three types of sand complexes, each type having different values wavelet-GK extremes. Complexes of the type 1 are the most promising in terms of reservoir development by the steam-thermal methods of extracting high-viscosity oil, since they contain a minimum amount of clay material filling the inter-grain space, which is largely filled with fluid. Complexes of the type 2 are promising in terms of development of a reservoir in the contact zone with complexes of the type 1. With the predominance of complexes of the type 3, the reservoir porosity and permeability decrease and as a result decrease reserves estimates.