Organic-matter-rich mud shale rock physical model establishing method

Abstract

The invention discloses an organic-matter-rich mud shale rock physical model establishing method. According to the method, pore shape influences are fully taken into consideration through the Wu (1966) two-dimensional pore surface ratio and / or four special Berryman (1980) three-dimensional pore shapes; critical porosity limitation influences are eliminated oriented to different pore types of critical porosity limitation through a differential effective medium theory, organic matter is used as solid inclusion compound of rock, solid substation is performed through a Brown-Korringa equation, and an organic-matter-rich mud shale rock physical model capable of predicting elastic wave speed is established. The organic-matter-rich mud shale rock physical model established with the method can approximate physical properties of the organic-matter-rich mud shale rock, and the longitudinal wave speed and the shear wave speed of a seismic wave in the organic-matter-rich mud shale rock can be accurately predicted. The efficiency for establishing the organic-matter-rich mud shale rock physical model is high.

Description

technical field [0001] The invention relates to a method for establishing a petrophysical model, in particular to a method for establishing a petrophysical model of organic-rich shale. Background technique [0002] Due to the complex lithology and pore morphology of mud shale, there is no effective petrophysical model to describe the elastic properties of mud shale. Core analysis and microscope observation show that the shale pores are mainly fractures, characterized by low porosity and low permeability, and have a high content of organic matter, some of which exist in the form of fracture fillings. Practice and laboratory analysis show that the existence of fractures and organic matter will significantly affect the elastic characteristics of shale, including bulk modulus and shear modulus. In order to simulate its elastic properties more accurately, it is necessary to consider the influence of fractures and organic matter. model research. [0003] An important aspect in s...

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Problems solved by technology

The reason why the velocity prediction with dry rock is used is mainly because the self-consistent theory itself is a high-frequency model, which assumes that the cavities are isolated from each other, and the relative motion between the fluids cannot occur, so it cannot fully take into account The influence of fluid on rock properties, and Berryman (1980) pointed out that there is a limit to the critical porosity of the self-consistent theory. Agnibaha Das (2009) believes that the effective porosity falls between 40% and 60%, which obviously does not meet most formations Pore ​​Condition Requirements

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