S-wave anisotropy from two dipole sonic data processing methods, confronted with fracture permeability, logs and cores

The present paper consists in two parts, determined by the historical emerging production of Dipole Sonic Imager (DSI) measurements and results early 1990’s. DSI data were processed following methods simultaneously developed France USA Schlumberger . In first part dipole sonic S-wave velocity obtained late 1993 are confronted with other borehole scientific MM-1, entirely cored extensively logged, as comprehensive project named Géologie Profonde de la (GPF), conducted Bureau Recherches Géologiques et Minières ( BRGM , i.e. French Geological Survey), Ardèche, southern France. 1994, José Perrin summarized integrated all information including preliminary from an azimuthal “rotation scan” slowness determination method quickly Schlumberger-France aiming at detecting only presence anisotropy a step. initial presented to industrial logging community April prior commercialization any splitting computer detection routine applied data. second focuses on comparison produced later time namely: a) commercial based cross energy minimization, October b) principal azimuth sorted method, 1995 further improved July 1997. After discussing discrepancies fast derived diverse specialists over several years, spare basis, authors expose constructive explanations paper. A limited overview latest processing developments has also been attempted better understand differing birefringence suggesting that rock formation immediate vicinity, up three times radius, may not be homogeneous along depth depending local geological context. Besides, Fast Azimuth split (FAZ) fits strike major regional faults parallel maximal horizontal palaeo-stress, which happens nearly orthogonal stress direction accepted geologists! case study suggests ought become more reliable, mainly accuracy precision FAZ. Additionally, efficiency semblance parameter for attenuation is pondered, where no detected receiver array.