Reservoir And Oil-Bearing Property Prediction Based OnWavelet And Fractal Theory

Along with the boom of nonlinear science, particularly when wavelet, fractaladvanced mathematical theory are called in the field of seismic exploration, havingbrought new clue for the development technology of the filed. Fractal theory is an importapproach to the description and study of irregular bodies in nature. Wavelet theory is anexcellent analytic tool in signal processing field, and is a powerful tool to reveal fractallocal scale property. In the paper, combining multi resolution analysis theory, implementtransformation of the signal from whole to part by means of wavelet transform ofdifferent scales, apply fractal idea to extract fractal feature to identify vertical andtransversal boundary of the thin sand-body, on this basis, use amplitude spectrum fractaldimension for reservoir oil-bearing property prediction.In the paper, on the basis of surveying and studying fundamental theory of wavelettransform and fractal dimension and comprehending its feature and interrelation, haveanalyzed the fractal feature of seismic wave through the power spectral of seismic waveaccording to FBM. In view of geology and seismic feature of thin sand-body, that is singlelayer is thin and the lithology changes fast in lateral, for predicting the space distribution ofthe thin sand-body, I have studied the fractal dimension method in variant scale and variantdirection. By means of making up geologic model demonstrate effectiveness andpracticability, through comparing with variant fractal dimension, I found multi-scalemulti-direction fractal dimension can show the space distribution of the thin sand-bodywell, and apply it to the western area of Zhenglizhuang oilfield in Dongying Sag, havingacquired preferable effect. Then, for reservoir oil-bearing property prediction, according toactual geological conditions, decompose seismic data by the multi-scale decomposition ofwavelet transforms, select pertinent scale, calculate the amplitude spectrum; Define scale invariant area according to the amplitude spectrum of oil and gas well, then compute thefractal dimension of the scale invariant area, the higher the value of the fractal dimension,the greater the possibility of reservoir oil-bearing property. Hereby, we predicted thereservoir oil-bearing property of the whole work area. The practice shows that thetechnology of fractal dimension is able to reflect the change of reservoir and oil and gasformation caused by seismic waveform, is a better method of reservoir and oil-bearingproperty prediction.