Evaluating Effect of Perforation on Borehole Acoustic Waveform Logging: A Numerical Study

Quantitative evaluation of perforation and its penetration depth is often desired in hydraulic fracturing design and oil recovery efficiency prediction, for which an effective method needs to be developed. We construct a perforated cased-borehole model for the field test configuration and simulate the elastic wave propagation in the model excited by a borehole monopole source using the finite difference method. The simulation results, after a multivariate regression analysis, yield a relationship for the perforation penetration depth versus the induced P-wave travel-time change and formation slowness. For field application purpose, borehole array acoustic logging with a perforated borehole model is simulated. The calculated waveform data, in conjunction with the above mentioned relationship, yield a good estimate of the perforation penetration depth. A field perforation test example is used to demonstrate the application of the proposed method.