Oil & gas prediction by multi-wave 2D time-frequency analysis method
Du Qi-zhen1, Bai Qing-yun1, Wang Xiu-ling2, Bi Li-fei2
1. College of Earth Resource and Information,China University of Petroleum,Dongying City,Shandong Province,257061;
2. Geophysical Research Institute,Shengli Oilfield Branch Company of Sinopec,Dongying City,Shandong Province,257022,China
Abstract：The main pay zone Ng58～10 in K71 well Block in Shengli Oilfield is characterized by fluvial facies,thin and interbeded deposition with severe heterogeneity.The traditional prediction method cannot make the precise prediction for oil gas.Based on multi-well interpretation results which were used as constraint,the multi-wave 2D time-frequency analysis method was used for the prediction of oil gas in the main pay zone.The exact flowchart is as below:(1) Interpreting the data of the multi-wells to obtain the interpretation results of the main pay zone Ng58～10,(2) conducting 2D time-frequency analysis for P-and converted wave sections to obtain the data volumes in time,frequency and space domain,then converting the 2D seismic sections to 3D data volumes by using 2D S-transform to analyze the characteristics of the oil and water in different frequency bands,and(3)applying difference calculation for the time-frequency data of the water zone from the well logging interpretation,taking the frequency band with the maximum difference as ideal frequency band and conducting the 2D time-frequency analysis for the P-and wave converted seismic data in the ideal frequency band to obtain the 2D instantaneous amplitude data.The field application results show that the seismic attributes extracted in ideal frequency band can amplify the difference between oil gas and water and highlight the oil gas anomaly,so the fluvial facies reservoir with rapid lateral variation could be better characterized.The location of the oil gas can be seen as bright spot on the P-wave seismic section,and as dark spot on the converted seismic section.
