Abstract:

This paper is concerned with an improved network model in acoustical application to petroleum logging and seismic exploration. Utilizing acoustic-electric analogue, we report in this paper a newly developed acoustic-logging network model. Important relationships amongst various physical factors are established, i.e. driving-voltage signal, electric-acoustic conversion of source-transducer, acoustic-electric conversion of receiver-transducer, the physical and geometrical properties of propagation media, as well as the measured logging signal. Technically, a driving-voltage convolution with electric-acoustic impulse response is used to substitute for some traditionally assumed acoustic-source functions on acoustic logging, e.g. Tsang wavelet, Ricker wavelet, Gaussian impulse wavelet, etc. With an improved understanding of the anisotropic effects on reflection/refraction between two different anisotropic rock slabs, the new network model can be used to determine the various properties of signal propagation in acoustic-logging, including propagation speed, phase factor, signal amplitude, and frequency information. In turn, it provides input for analysis of amplitude variations with offset (AVO). Corresponding to the improved network model, with available logging and seismic exploration data, a new algorithm for analysis of amplitude variation has been developed to explore new oil reservoirs or gas fields.