Method and device for determining formation water saturation

Abstract

The invention discloses a method and a device for determining the water saturation of a stratum, and belongs to the field of oil well logging technologies. The method includes selecting series representative cores of a measured region, and measuring values of porosities POR of the series cores and values of specific resistance R<w> of saturated stratum water of the cores; creating a functional relation m(POR, R<w>) among bond indexes m of the cores, the porosities POR of the cores and the specific resistance R<w> of the stratum water; creating a functional relation n(R<w>, POR) among saturation indexes n, the porosities POR of the cores and the specific resistance R<w> of the stratum water; solving the water saturation S<w> of the stratum by the aid of an Archie water saturation interpretation model. The device comprises a selecting module, a parameter measuring module, a bond index creating module, a saturation index creating module and a saturation computing module. The method and the device have the advantages that the functional relations among values of the bond indexes m, values of the saturation indexes n, the porosities POR and the specific resistance R<w> of the stratum water are created, so that the values of the bond indexes m, the values of the saturation indexes n, the porosities POR and the specific resistance R<w> of the stratum water are relevant to one another, and the computed water saturation of the stratum is accurate and reliable.

Description

technical field [0001] The invention relates to the technical field of petroleum well logging, in particular to a method and a device for determining the water saturation of formations. Background technique [0002] Accurate calculation of formation water saturation is the basis of logging formation evaluation, and the most common method to determine formation water saturation in formation evaluation is the Archie water saturation model calculation method. This method later derived some other logging evaluation methods, and these methods were also developed on the basis of Archie's water saturation calculation model. [0003] Archie's water saturation interpretation model is established on the basis of pure sandstone lithoelectric experiments under the condition of high salinity solution, and it is the theoretical basis for quantitative interpretation of logging data. [0004] The classic Archie formation water saturation formula is: [0005] (1) The parameters to be det...

AI Technical Summary

Problems solved by technology

However, it is more complicated to solve the cementation index m(Rw, φ) and saturation index n(Rw, φ), which needs to calculate and solve multiple nested undetermined coefficients, which greatly increases the amount of calculation, reduces the calculation accuracy, and increases the error source

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