中国东部地区油气层的AVO检测标志

DETECTION OF INDICATIONS FOR RESERVOIR BY AVO, EASTERN PART OF CHINA

It is a fundamental work for oil/gas detection to predict the reflection characteristic of the reservoir, because it can setup appropriate indications for oil/gas detection. The key link for reservoir reflection character prediction is the correct determination for the physical parameters of the rock. The physical parameters of the rock in the eastern part of China were examined with the data provided by the long spaced full-wave acoustic logging as well as the density logging based on the Schlumberger's technique. In line with the corrected longitudinal wave velocity of the shallow mudstone of the Shengli Oil Field,the physical parameters of the shallow mudstone were modified. The procedure of the analogue acquisition and the analogue processing of the seismic data were made by the AVO technique. The indications of the reflection amplitude of the reservoir aftei stack,the character of the reservoir in AVO and waveform before stack were given after the modelling for the top of the reservoir and the thin oil -beanng formation have been made befor and after stacking. Examples show that it woulo be more in comformity with the practice to found the indications for oil/gas detection before and after the stack has been made,but it must be a correct determination for the physical parameters of the rock. The complete procedure for oil/gas detection should be:to predict the reflection character of the reservoir before and after stack by AVO technique ,then,to search for the reflection amplitude anomaly of the reservoir on seismic section and to analyse the character of the amplitude versus the offset on the record before stack,and then,to assertain the oil - bearing formation.