Rock physical modeling method for grey background turbidite reservoir

Abstract

The invention discloses a rock physical modeling method for a grey background turbidite reservoir. The rock physical modeling method comprises the following steps that S1, an equivalent matrix elasticity modulus of a rock matrix is solved on the basis of a well-logging interpretation result; S2, a dry rock framework modulus is solved based on a K-T model and a dynamic effect model (DEM); S3, a bulk modulus of a mixed fluid is calculated through a Wood equation; S4, a grey turbidite elasticity modulus of a saturated fluid is calculated and solved through a Gassmann equation; S5, the longitudinal wave speed, the transverse wave speed and the density of grey turbidite of the saturated fluid are calculated; and S6, the longitudinal wave speed calculated in the step S5 and the actually measuredlongitudinal wave speed are compared and iteratively analyzed till a rock physical model meeting the error requirements is obtained. On the basis of a traditional Xu-White sand shale model, the K-T model, a differential equivalent medium model and the DEM are fully combined, the lithologic coupling problem of sand shale and carbonatite mixed diagenesis can be solved effectively, and elastic parameters of a grey background turbidite formation are finely predicted.

Description

technical field [0001] The invention relates to the field of petrophysical modeling, in particular to a petrophysical modeling method for lime background turbidite reservoirs. Background technique [0002] Seismic inversion is the main means and method of formation lithology prediction, and rock physics analysis is the key link and technical core of seismic inversion. Petrophysical analysis shows that: in general, in consolidated sand-shale formations, the velocity of sandstone is higher than that of mudstone, and the density of sandstone framework is higher than that of mudstone framework. Therefore, post-stack wave impedance inversion can often easily distinguish sandstone and mudstone . However, due to its complex lithological combination, turbidite reservoirs in the limestone background mainly exhibit the following petrophysical characteristics: (1) In the limestone background, the P-wave velocity of the limestone mudstone is higher than that of the mudstone, and the P-...

AI Technical Summary

Problems solved by technology

However, due to its complex lithological combination, turbidite reservoirs in the limestone background mainly exhibit the following petrophysical characteristics: (1) In the limestone background, the P-wave velocity of the limestone mudstone is higher than that of the mudstone, and the P-wave velocity of the limestone sandstone is higher than that of the mudstone. The P-wave velocity is higher than that of sandstone, which makes it difficult to distinguish turbidite from lime mudstone and lime sandstone in post-stack wave impedance inversion; (2) In the limestone background, the shear wave velocity of lime mudstone is slightly lower than that of mudstone, and the shear wave velocity of lime sandstone is higher than that of sandstone. The shear wave velocity is significantly reduced. Therefore, for limestone background turbidite reservoirs, making full use of shear wave information is a more effective method to identify turbidites; (3) due to the high cost of shear wave logging, shear wave velocity data are often lacking in actual production research, so It is necessary to adopt a suitable petrophysical modeling method to predict the shear wave velocity, so as to realize the effective prediction of the lithology of the lime background turbidite and improve the accuracy of reservoir prediction

Images