Method and device for determining layer velocity at seismic scale

Abstract

The present invention relates to a method and device for determining the layer velocity at the seismic scale. The method includes: obtaining the layer velocity under the logging frequency band; determining the rock physical statistical relationship according to the layer velocity under the logging frequency band and the corresponding known quality factor Correlation coefficient; establish the first objective function according to the layer velocity in the logging frequency band and the correlation coefficient in the petrophysical statistical relationship, and obtain the layer velocity at the seismic scale satisfying the velocity-dispersion relationship according to the first objective function; determine the current position The length of the scale coarsening window, using the length of the scale coarsening window at the current position to obtain the number of sample points in the scale coarsening window at the current position; and determining the current position according to the layer velocity at the seismic scale satisfying the velocity-dispersion relationship and the corresponding number of sample points The layer velocity after the coarsening of the seismic scale at the current position is corrected to obtain the layer velocity at the seismic scale that accurately reflects the travel time information of seismic wave propagation.

Description

technical field [0001] The invention relates to the technical field of petroleum geophysical exploration, in particular to a method and device for determining layer velocity under the seismic scale that can accurately reflect travel time information of seismic wave propagation. Background technique [0002] With the continuous deepening of oil and gas exploration and development, how to make full use of the high-resolution characteristics of well logging data in the vertical direction and the control ability of 3D seismic data in the lateral direction, and improve reservoir prediction and oil and gas identification under the constraints of limited logging data Reliability is an inevitable trend in the development of oil and gas seismic exploration technology. Well seismic calibration is a bridge for accurate cross-scale calibration of logging data and seismic data. Through the production of fine synthetic seismic records, the quantitative mapping between the elastic paramete...

AI Technical Summary

Problems solved by technology

Among them, the center frequency of acoustic logging is usually 10-20kHz, while the frequency range of seismic exploration is usually 5-100Hz. That is to say, there is a big difference between the frequency of acoustic logging and seismic exploration data. There is an obvious dispersion problem in the velocity of the data. The difference in velocity characteristics at two different frequencies leads to differences in synthetic seismic records, and also affects the time-depth conversion accuracy in the process of synthetic seismic records.

In addition, there is a large difference in the vertical resolution scale between well logging data and seismic data, and the direct production of synthetic seismic records at the well logging data scale will inevitably lead to a certain difference between well side channels at the seismic scale. Conducive to fine calibration and comparison of well seismic data

Moreover, in the actual production process, it is usually necessary to artificially stretch / compress or drift the synthetic seismic records, resulting in large errors in the calibration results, which affect the accuracy of seismic interpretation. The time-depth relationship cannot meet the accuracy of the wellside seismic trace calibration

[0003] To sum up, how to obtain the interval velocity that satisfies the calibration accuracy of side-hole seismic traces at the seismic scale is the key to solving the differences in scale and frequency characteristics between well logging data and seismic data and the low accuracy of conventional synthetic seismic record production methods

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