Speed modeling method based on true earth surface and floating datum plane

Abstract

The invention discloses a speed modeling method based on a true earth surface and a floating datum plane. The method includes the steps that a superficial part speed model is built by using superficial part speed resources reflected by excitation well depth, uphole time, short-refraction information and logging information; medium-deep part speed spectrum resources are processed, and a medium-deep part speed model is built; on the basis of a fusion technology, the superficial part speed model and the medium-deep part speed model are fused to be a full speed model based on the true earth surface and the floating datum plane; on the basis of a newly derived average statics correcting value method floating datum plane sea level elevation expression, the condition that the floating datum plane deviates from the earth surface is quantified, and a full speed model datum plane correction technology is innovatively built. The full speed module obtained according to the method conforms to the underground geological rules better, and not only can be applied to a prestack depth migration link of earthquake information processing to improve migration imaging precision, but also can be applied to a time-depth conversion link of earthquake information interpretation to improve structural interpretation precision.

Description

technical field [0001] The invention relates to the technical field of seismic exploration velocity modeling, and more specifically, relates to a velocity modeling method based on a real surface or a floating datum. Background technique [0002] In existing seismic data interpretation techniques, conventional velocity modeling and variable-velocity time-depth conversion are generally based on a fixed datum. Firstly, it is necessary to migrate the first-hand velocity spectrum and time-shift of the seismic body from the floating datum to the fixed datum, and then perform calibration interpretation, velocity modeling and time-depth conversion based on the fixed datum data, in an attempt to accurately locate the data in the depth domain. Structural or Hydrocarbon Favorable Sites Interpreted by Time Domain Seismic Signals. [0003] Under complex surface conditions, the positioning accuracy of velocity modeling and time-depth conversion based on a fixed datum is low. Taking the i...

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Problems solved by technology

[0003] Under complex surface conditions, the positioning accuracy of velocity modeling and time-depth conversion based on a fixed datum is low. Taking the interpretation of 3D seismic data in a work area in the northern Tarim Basin as an example, the ground elevation of the work area is between 986 and 2027m. The relative error of structural map depth obtained by fixed datum velocity modeling is 11.46%, and the standard deviation is 232m

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