Method for three-dimensional velocity geological modeling with structures and velocities randomly arranged

A method for three-dimensional velocity geological modeling with structures and velocities randomly arranged, comprising:

• determining a base point in a three-dimensional space, building an equation according to the base point to determine a planar layered model, and complicating a tilt layer of the planar layered model to build a fold layer model of a curved surface in the three-dimensional space;
• building a three-dimensional fault folded model based on the three-dimensional surface fold layer model combined with a fault plane of a random reference point and displacement of each point in a global coordinate system;
• building a velocity model containing salt body based on the three-dimensional fault folded model, and simulating salt body intrusion in a geological body of certain depth;
• and
• performing a random velocity amplitude to realize three-dimensional velocity modeling according to the layered type which has been set and according to the set velocity range and the velocity difference range between each layer of geology;
• the complicating a tilt layer of the planar layered model specifically comprising:
• the planar layered model is determined by building an equation according to the base points, and the different layer models are divided into different categories;
• a fluctuation function is built for each point based on the plane model;
• by adjusting a period and amplitude of a trigonometric function in the fluctuation function, a tilt term is built for the surface, the tilt layer is further complicated, and the fold layer model of the surface in the three-dimensional space is built.