Fracture Evaluation Using Crossing Dipole Acoustic Logging Data in Horizontal Well

Horizontal well technology has been widely used in petroleum exploration and development. Evaluating formation fractures out of horizontal well can provide effective decision-making basis for testing. Acoustic logging has been proved to be a good technique for formation evaluation in vertical well. Since acoustic logging shows its efficiency in vertical well, it can be speculated to be a potential method for that in horizontal well. Research on acoustic logging wave filed characteristics of fracture formation well is the theoretical foundation of fracture evaluation.

This paper proposed a fracture evaluation method in horizontal well by crossing dipole acoustic logging. Fracture intensity has been proved to be an effective parameter of fracture evaluation ( Coates et al, 1985 ). Firstly, the equivalent medium theory is applied to finite difference simulation of crossing dipole wave field. Then the influence of fracture intensity to waveform has been analysed. Considering dipole waves'frequency dispersion, we adopted a high resolution frequency dispersion analyse method— Amplitude Phase Estimation (APES, Li, 2013 ), which can be used to backward derive the fracture intensity by calculating formation anisotropy. The high consistency of derived results and initial simulation settings demonstrates the validity and capability of the numerical simulation. Meanwhile, it proves that it is viable to evaluate formation fracture intensity using crossing dipole logging data.