Method and device for determining reservoir lithology

Abstract

The invention provides a method and device for determining reservoir lithology. The method comprises the steps that whether a reservoir to be determined is a sand-mudstone formation; under the condition that the reservoir to be determined is the sand-mudstone formation, the stratum correction constant quantity of the reservoir to be determined is obtained; the low-frequency component of an interval transit time curve and the shale content of the reservoir to be determined are obtained; according to the stratum correction constant quantity, the shale content and the low-frequency component of the interval transit time curve of the reservoir to be determined, a reservoir characteristic curve of the reservoir to be determined is obtained through calculation; and according to the reservoir characteristic curve, the reservoir lithology of the reservoir to be determined is determined. In the embodiment, the distinguishing precision of sand shale is greatly improved, and therefore the purpose of improving the reservoir predicting effect is achieved.

Description

technical field [0001] The invention relates to the technical field of geological exploration, in particular to a method and a device for determining reservoir lithology. Background technique [0002] At present, the wave impedance inversion method can generally be used to determine the reservoir lithology. Since the P-wave impedance difference between sandstone and mudstone in the reservoir is not obvious, and the P-wave impedance of gas-bearing sandstone and mudstone overlaps seriously, it is difficult to predict reservoir lithology using P-wave impedance information. For prestack wave impedance inversion, the reservoir lithology can be determined according to the variation of amplitude with angle (ie, offset) in the work area. However, for the sand-mudstone work area where the amplitude changes little or remains unchanged with the increase of angle or offset, the prediction of reservoir lithology by using the pre-stack wave impedance inversion method will be obviously li...

AI Technical Summary

Problems solved by technology

However, for the sand-mudstone work area where the amplitude changes little or remains unchanged with the increase of angle or offset, the prediction of reservoir lithology by using the pre-stack wave impedance inversion method will be obviously limited, and the inversion results are also relatively poor. It is difficult to reflect the gas content of the actual underground reservoir

[0003] For the above problems, no effective solution has been proposed

Images