Reflection of frequency attenuation affects the detection of bright spots in the conventional tree classification. A "cutting method" is presented. The whole seismogram is cut into small sections. Block diagram of the cutting method and tree classification is shown in Figure 2. In every section, training traces are randomly selected. Envelope threshold is determined by 2-3 standard deviation of the noise from seismogram. Threshold of instantaneous frequency is determined by using a cluster analysis and the resulting separability information. Then high amplitude and low frequency area can be detected. After determining the tree classifier of envelope and instantanteous frequency from training traces, classification is performed in the small section. A new definition of polarity is also presented here. Polarity reversal also checks where the gas or oil/water reflection is. The major advantage of the cutting method is that overlapping distribution of the envelope and instantaneous frequency can be taken out. A simulation of three kinds of zero-phase Ricker wavelet and a relative amplitude seismogram of bright spots are presented. The results are quite satisfactory.
|Number of pages||3|
|State||Published - 1 Jan 1993|
|Event||1983 Society of Exploration Geophysicists Annual Meeting, SEG 1983 - Las Vegas, United States|
Duration: 11 Sep 1983 → 15 Sep 1983
|Conference||1983 Society of Exploration Geophysicists Annual Meeting, SEG 1983|
|Period||11/09/83 → 15/09/83|