Saturation index prediction method based on pore structure

Abstract

The invention discloses a saturation index prediction method based on a pore structure. The saturation index prediction method includes the steps that firstly, a representativeness core sample of a target layer is selected, a salt solution with a certain concentration is used for saturation, and the nuclear magnetic resonance spectrums T2 of a saturated rock core are measured; secondly, a centrifugal machine is used for centrifuging the saturated rock core under different rotating speeds, and the nuclear magnetic resonance spectrums T2 of the rock core in different centrifugal states are measured; thirdly, the geometric mean value T2 of the nuclear magnetic resonance spectrums T2 of the saturated rock core, the geometric mean value T2 of the nuclear magnetic resonance spectrums T2 of the rock core in different centrifugal states and the water saturation of the rock core are calculated; fourthly, the distribution change rate of the spectrums T2 is constructed, the pore structure index n' of the rock core is obtained according to the change relation curve of the distribution change rate of the spectrums T2 and the water saturation; and fifthly, the saturation index of the rock core is predicted according to the pore structure index n' of the rock core, and the saturation index of the target layer is determined.

Description

technical field [0001] The invention relates to the technical field of well logging evaluation of oil and gas reservoirs in petroleum exploration, in particular to a method for predicting saturation index based on pore structure. Background technique [0002] In oil exploration and development, the main task of well logging evaluation is to complete the identification and quantitative evaluation of oil and gas layers based on a series of parameters obtained from well logging. Among them, the oil saturation parameter in a series of parameters can affect the judgment of pay layer type and the accuracy of reserve calculation, so it is extremely important in the evaluation of reservoir logging in oil and gas reservoirs. [0003] On the one hand, oil saturation is the basic basis for identifying oil and gas layers. At present, when performing well logging evaluation, it is usually necessary to use saturation as the basis for dividing production layers to determine the types of o...

AI Technical Summary

Problems solved by technology

For tight sandstone reservoirs, due to their low porosity and permeability, especially the fine reservoir throat and complex pore throat structure, it is often difficult to carry out rock electrical experiments on tight sandstone, that is, the usual displacement method It is difficult to displace the water in tight sandstone, that is, it is difficult and time-consuming to carry out electrical experiments on tight sandstone

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