Method for establishing three-part automatic parallel-series electric conduction saturation degree model

Abstract

The invention discloses a method for establishing a three-part automatic parallel-series electric conduction saturation degree model, which can solve the difficult problem that the Archie water saturation formula is not applicable due to the complex structure of an aperture gap of a compact sandstone reservoir. The aperture gap of the compact sandstone reservoir is divided into three parts, namely a large part, a medium part and a small part; under the proper hypothesis condition, the resistivity of each part of the aperture gap is given by the Archie water saturation formula, in reservoir rock, series connection conduction and parallel connection conduction synchronously exist and are automatically coupled in a series-parallel connection manner; the proportions of series connection and parallel connection change along with the change of the water saturation, and further a reservoir rock total resistivity formula is deduced, namely a three-part automatic parallel-series electric conduction saturation degree model; and series-parallel connection weight coefficient is fitted via data calculated by using a three-dimensional digital rock core technology, and the coefficient of each part is fitted by using rock electric test data. According to the invention, via practical data processing and analyzing, the model further approaches the real electric conduction condition of the reservoir rock, and the phenomenon of incorrect calculation of the water saturation, which is caused by a non-Archie phenomenon, is effectively prevented.

Description

Technical field [0001] The invention relates to a saturation evaluation method in the field of logging in the petroleum exploration and development industry, in particular to a method for establishing a three-component automatic hybrid conductive saturation model. Background technique [0002] In 1942, Archie published the famous paper "The electrical resistivity log as an aid in determining some reservoir characteristics" in the American Petroleum Technology Journal, which effectively linked resistivity logging with porosity logging, and established The foundation of well reservoir evaluation has epoch-making significance. [0003] In the experiment, Archie used salt water with different resistivity values ​​to 100% saturate the same pure sandstone core, and measured the resistivity R of the salt water in each experiment. w And the corresponding rock sample resistivity R 0 , Measure the effective porosity of the rock sample at the same time, and then calculate the different R of t...

AI Technical Summary

Problems solved by technology

However, with the reduction of the lower limit of reservoir development in oilfields, non-Archie phenomena have appeared in low-porosity, low-permeability reservoirs and tight sandstone reservoirs, and the relationship between water saturation and resistivity is no longer the only corresponding relationship, such as Mud, pore structure, wettability and other factors will affect the water saturation, thus making the Archie saturation model no longer applicable

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