Iteration acquisition method for first arrival wave

Abstract

The invention relates to an iteration acquisition method for a first arrival wave processed by petroleum geophysical prospection data. The method comprises the following steps of: calculating an energy ratio at each sampling point to acquire an energy ratio curve; determining a first arrival prediction value; finding the maximum amplitude value by using the first arrival prediction value as a starting point; calculating an absolute value and an average value of a time difference of adjacent first arrivals; calculating a reliability coefficient in an arrangement way by using time of one first arrival and time of a front first arrival and a rear first arrival; and performing Lagrange polynomial fitting interpolation on a first arrival with the reliability coefficient of 0 by using front and rear adjacent four reliable first arrivals to acquire a first arrival prediction value. By the method, first arrival time in complicated areas influenced by larger variation of a first arrival wave shape, mutual interference of various waves, external interference and the like can be acquired accurately, and the problem of a first arrival acquisition method is solved.

Description

technical field [0001] The invention relates to a petroleum geophysical prospecting data processing technology, and is a method for iteratively picking up first arrival waves. Background technique [0002] For the first-arrival picking in the processing of petroleum geophysical exploration data, the first-arrival time of each channel was manually picked up in the early stage. This method often has a huge workload, and the number of channels even exceeds 10,000. , Labor-intensive, very complicated work. With the continuous deepening of seismic exploration and the continuous improvement of data processing accuracy, it is very important to pick up the first arrival of seismic waves accurately and quickly. In refraction static correction, VSP interpretation, shallow refraction exploration and tomography exploration, the travel time of the first arrival wave is often used to invert medium parameters such as surface velocity and thickness, especially in some complex surface areas...

AI Technical Summary

Problems solved by technology

The energy ratio formula is too sensitive to the energy change of the interference wave before the arrival of the first arrival, and the picking error of the first arrival is large for poor data

[0008] To sum up, there are many methods for automatic first-arrival picking. For data in areas where the seismic record background is relatively calm and the first-arrival waveform is simple, the general first-arrival picking method can meet the requirements, but for complex areas, due to the The waveform changes greatly, various waves interfere with each other, and at the same time, due to the influence of external interference, etc., it is often difficult to obtain accurate first arrival time, which has always been a difficult problem for the first arrival picking method

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