Shale gas reservoir crustal stress logging prediction method based on rock physics model

Abstract

The present invention relates to a shale gas reservoir crustal stress logging prediction method based on a rock physics model. According to the method, a shale gas reservoir rock physics model which takes kerogen particles into consideration is established, so as to predict a longitudinal and transverse wave velocity of the logging; based on the above, a maximum and minimum horizontal principal stress and a fracture pressure of the reservoir are calculated; and an accurate stress assessment of a shale gas reservoir is carried out while a transverse wave logging is not provided. The beneficial effects of the invention are that: the rock physics model in line with characteristics of the shale gas reservoir is established to improve precision of the prediction velocity; and based on the rock physical model, the maximum and minimum horizontal principal stress and the fracture pressure are obtained, so that while the measured transverse wave logging data are not provided, the underground stress can be predicted on the basis of a conventional logging curve, and the prediction result is high in accuracy.

Description

Technical field

[0001] The invention belongs to the field of in-situ stress logging prediction of shale gas reservoirs, and in particular relates to a shale gas reservoir in-situ stress logging prediction method based on a petrophysical model. Background technique

[0002] For shale gas reservoirs, since fracturing reforms directly affect gas production, the prediction of underground stress determines the quality of fracturing reforms. There are many well-logging evaluation models for reservoir in-situ stress, the more mature ones are Mohr Coulomb model, Huang Rongzun model (see Reference 1), uniaxial strain model, etc. Through these models to obtain the maximum and minimum horizontal principal stresses, and then to obtain the fracture pressure, stress gradient, etc., the reservoir can be evaluated; but the application of these models must be based on the more accurate Young's modulus, Poisson's ratio and other rock mechanics Parameters are used as input parameters, and accurate...

Examples

specific Embodiment approach

[0024] Such as figure 1 Shown is the flow chart of the method for predicting in-situ stress logging in shale gas reservoirs based on petrophysical models. First, the mineral volume, porosity, saturation, and kerogen volume in the formation are obtained through logging interpretation; and obtained through rendezvous analysis The elastic modulus and density of the main minerals. The elastic modulus and density of the fluid are obtained through literature research. The elastic parameters here specifically refer to the bulk modulus and shear modulus; the logging interpretation results are introduced into the newly established shale gas reservoir The petrophysical model, by adjusting the pore type distribution spectrum parameters in the petrophysical model, iteratively calculates the longitudinal wave velocity and the shear wave velocity. Use the predicted longitudinal and transverse wave velocities to calculate the dynamic Young's modulus and Poisson's ratio, and convert the dynamic...

Technical field

[0001] The invention belongs to the field of in-situ stress logging prediction of shale gas reservoirs, and in particular relates to a shale gas reservoir in-situ stress logging prediction method based on a petrophysical model. Background technique

[0002] For shale gas reservoirs, since fracturing reforms directly affect gas production, the prediction of underground stress determines the quality of fracturing reforms. There are many well-logging evaluation models for reservoir in-situ stress, the more mature ones are Mohr Coulomb model, Huang Rongzun model (see Reference 1), uniaxial strain model, etc. Through these models to obtain the maximum and minimum horizontal principal stresses, and then to obtain the fracture pressure, stress gradient, etc., the reservoir can be evaluated; but the application of these models must be based on the more accurate Young's modulus, Poisson's ratio and other rock mechanics Parameters are used as input parameters, and accurate...

Examples

specific Embodiment approach

[0024] Such as figure 1 Shown is the flow chart of the method for predicting in-situ stress logging in shale gas reservoirs based on petrophysical models. First, the mineral volume, porosity, saturation, and kerogen volume in the formation are obtained through logging interpretation; and obtained through rendezvous analysis The elastic modulus and density of the main minerals. The elastic modulus and density of the fluid are obtained through literature research. The elastic parameters here specifically refer to the bulk modulus and shear modulus; the logging interpretation results are introduced into the newly established shale gas reservoir The petrophysical model, by adjusting the pore type distribution spectrum parameters in the petrophysical model, iteratively calculates the longitudinal wave velocity and the shear wave velocity. Use the predicted longitudinal and transverse wave velocities to calculate the dynamic Young's modulus and Poisson's ratio, and convert the dynamic...

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