Shale gas stratum geostress prediction method based on three-dimensional seismic data

Abstract

A method for predicting the in-situ stress of shale gas formations based on 3D seismic data belongs to the field of shale gas geophysical exploration. The method first uses 3D pre-stack seismic data and logging data to perform pre-stack elastic parameter inversion to obtain shale The elastic parameters of the gas formation; then the formation pressure is calculated by using the seismic layer velocity obtained based on the 3D post-stack seismic data and the stacked velocity data; then the curvature and horizontal direction of the shale gas formation are calculated based on the 3D post-stack seismic data and seismic horizon data Structural strain; finally, according to the linear isotropic combined spring model, the maximum horizontal principal stress, the minimum horizontal principal stress and the horizontal stress difference of the shale gas formation are calculated using three-dimensional data such as elastic parameters, formation pressure, and structural strain. The beneficial effect of the invention is that the three-dimensional geostress data body of the shale gas formation with high precision can be obtained effectively.

Description

Technical field [0001] The invention belongs to the field of shale gas geophysical exploration, and particularly relates to a method for predicting in-situ stress of a shale gas formation based on three-dimensional seismic data. Background technique [0002] (1) Professional terms involved [0003] (1) In-situ stress: In-situ stress is a mechanical parameter of the earth's solid medium that is affected by gravity, a variety of earth tectonic dynamics and astronomical dynamics, and additional dynamics of exploration engineering, which causes response deformation in the internal elements of the medium. The maximum horizontal principal stress and the minimum horizontal principal stress are the important basis for the well trajectory design in the shale gas development process. [0004] (2) Formation pressure: Formation pressure refers to the pressure generated by the pore fluid of the formation. When the pores of the formation are connected, its value is equal to the hydrostatic pressu...

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Problems solved by technology

[0011] The purpose of the present invention is to provide a ground stress prediction method for shale gas formations based on three-dimensional seismic data for the ground stress prediction in the field of shale gas exploration and development. It is impossible to simulate the real state of the formation under the double action of horizontal tectonic action and formation pore pressure, so it is impossible to accurately evaluate the real stress state of the low-porosity and low-permeability shale gas formation, which can be used to guide the pre-drilling prediction of oil and gas, Especially the pre-drilling prediction of shale gas and the design of horizontal well trajectory

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