Optimisation of hydraulic fracture placement design in anisotropic shale reservoirs using azimuthal LWD sonic and spectral gamma ray analysis

Abstract

Hydraulic fracturing (fracking) of shale resources has become a trend in the oil and gas industry that is associated with exorbitant costs. In order to increase the efficiency of fracture stimulation, considerations have to be given to the anisotropic tendencies of shale petrophysical and geomechanical properties along wellbore laterals where fractures are hydraulically induced. In this study, an approach for the accurate quantification of vertical transverseisotropy (VTI) and resultant anisotropic properties along shale wellbore laterals using an LWD azimuthal sonic log was investigated. Using the case study of a Marcellus shale well in Northeastern Pennsylvania having azimuthal sonic data, a work flow for obtaining anisotropic properties, critical to fracture stimulation design was developed. An algorithm for the characterisation of wellbore geomechanical quality based on estimated VTI anisotropy, anisotropic closure stress and brittleness was also developed..