Permeability logging method and its application based on pure Stoneley waves induced by continuous low frequency planar shock waves

Shock-tube core experiments have provided an important finding, that is, the low frequency acoustic field generated by planar shock waves can induce pure Stoneley waves in a borehole, with their amplitude attenuation demonstrating a definite correlation with fracture width and permeability. Accordingly, a method was proposed to transmit low frequency planar shock waves in a borehole through axially polarized axial vibration, thereby continuously inducing pure Stoneley waves. Equations were also derived for calculating fracture width and permeability from Stoneley wave amplitude attenuation. Moreover, the permeability logging prototype was successfully developed, together with acquisition and processing software incorporating amplitude-attenuation extraction and permeability calculation. The operability, stability, and measurement performance of the logging tool were tested and verified in two standard wells, R91 and LS2. In the 10 000-m extra-deep well SDTK1 in the Tarim Basin, matrix and fracture permeability curves of extra-deep carbonate formations were obtained in a single downhole logging. The results were immediately calibrated with the data of quasi-in-situ nuclear magnetic resonance (NMR) permeability measurement on full-diameter drilling cores taken from the same interval of the well. The results show that the proposed method performs well in quantitative permeability evaluation of extra-deep carbonate reservoirs and provides a new technical approach for permeability logging evaluation in other types of reservoirs. This theoretical and technological breakthrough provides an innovative means for quantitative permeability evaluation in reservoir logging.