Method for determining the characteristic frequency of low frequency photography and its application in the deep water area of the South China Sea
When the seismic wave passes through the oil and gas reservoir,the low frequency accompanying shadow is the low frequency strong reflection energy mass produced under the oil and gas reservoir,and the low frequency accompanying shadow has been widely used in the prediction of oil and gas reservoir as an oil and gas mark.The characteristic frequency is an important parameter in the research of low-frequency companion shadow.Most of the predecessors use the method of frequency scanning to find out the most obvious single-frequency profile of low-frequency companion shadow.The selection of frequency depends on the manual determination of researchers,which has the problem of low accuracy.In order to solve this problem,according to the multi-layer fast-slow P-wave conversion model and the asymptotic form of the reflection and transmission coefficient of fast-slow P-wave in two-phase medium,the low-frequency characteristic frequency formula of the multi-layer fast-slow P-wave conversion model is derived in this paper.the key factors affecting the characteristic frequency are gas reservoir permeability,gas reservoir thickness and medium modulus.In this method,the low-frequency shadow characteristic frequency is calculated from the actual data,and the low-frequency shadow section corresponding to the characteristic frequency in the actual seismic data is verified by generalized S-transform.the results show that the calculation of low-frequency shadow characteristic frequency is correct.
Reservoir predictionLow frequency accompanying shadowCharacteristic frequencyTwo-phase mediumAsymptotic equation
NETL
NSTL
万方数据
