My PhD Thesis, PDF 3MB - Stanford University
My PhD Thesis, PDF 3MB - Stanford University
My PhD Thesis, PDF 3MB - Stanford University
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Chapter 2<br />
Elastic Waves in Radially Multi-layered<br />
Media<br />
In this chapter, a new method based on generalized reflection and transmission<br />
coefficients is proposed to calculate synthetic seismograms in radially multi-layered<br />
media without vertical variation (media with vertical variation are considered in Chapter<br />
3). This method can be used to efficiently simulate full waveform acoustic logging,<br />
crosswell seismic profiling, and single borehole profiling in situations where we need to<br />
consider borehole effects. The formulation is tested by comparing the numerical results<br />
with available previous work, showing excellent agreement. Because of the use of the<br />
normalized Hankel functions and the normalization factors, this new algorithm for<br />
computing seismograms is numerically stable even for the high frequency problem.<br />
Thus, we can simulate some models that can not be solved by other methods. An<br />
example of this is given in Section 2.5.1. In Chapter 5, I will apply this method for<br />
acoustic full waveform logging to investigate the effects of complex invaded zones on the<br />
geometrical spreading and attenuation estimation for P waves.<br />
2.1 INTRODUCTION<br />
Sonic logging in cased boreholes is useful for evaluating the quality of the cement<br />
job. Although acoustic logging in open boreholes is common, effort is also being made<br />
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