Improved seismic horizon velocity field calculation method applicable to prediction of formation pressure

Abstract

The invention relates to an improved seismic horizon velocity field calculation method applicable to prediction of formation pressure and belongs to the field of exploration of physical geography. According to the method, a subsurface formation is divided into a background formation section and a target formation section, wherein the velocity of the seismic horizon of the background formation section is obtained with a three-dimensional constraint DIX formula inversion method, and the velocity of the seismic horizon of the target formation section is obtained with a post-stack wave impedance inversion method; then, the velocity of the seismic horizon of the target formation section is subjected to three-dimensional edge-preserved smoothing processing, and the defect of high heterogeneity of the velocity of the seismic horizon of the target formation section is overcome; velocities of the seismic horizon of the background formation section and the seismic horizon of the target formation section are subjected to data fusion processing with a Gaussian weighted filtering method, and non-authentic mutation of the velocity of the seismic horizon at a transition region of the background formation section and the target formation section is effectively suppressed; accordingly, a seismic horizon velocity field for formation pressure prediction is obtained. The obtained seismic horizon velocity field has the characteristics of a local or regional stable field and has the consistent characteristics with the pressure field of the subsurface formation.

Description

technical field [0001] The invention belongs to the field of exploration geophysics, and in particular relates to an improved seismic layer velocity field calculation method suitable for formation pressure prediction. Background technique [0002] (1) The technical terms involved [0003] (1) Formation pressure: Formation pressure refers to the pressure generated by the pore fluid in the formation, and its value is equal to the hydrostatic pressure (that is, the pressure generated by the vertical water column from the surface to the target layer) when the formation pores are connected. [0004] (2) Distribution characteristics of underground formation pressure: In the same set of lithologic formations, due to the permeability of the formation, the formation with high formation pressure will transmit pressure to the formation with relatively low pressure, so the distribution of formation pressure in the underground geological body is often regional , contiguous and gradient ...

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Problems solved by technology

[0022] The purpose of the present invention is to provide an improved seismic layer velocity field calculation method suitable for formation pressure prediction for formation pressure prediction in the field of exploration geophysics, aiming at solving the problem caused by inaccurate seismic layer velocity information in the formation pressure prediction process The problem of inaccurate pressure coefficients of intervals can be used to guide the exploration and development of oil and gas, especially the exploration and development of shale gas

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