Far and Near Wellbore Fracture Characterization Using High Resolution Borehole Images and Acoustic Imaging

Far and near wellbore natural fracture systems characterization is key element for the successful exploitation of tight reservoirs, where one of the dominant aspects is permeability. Carbonate reservoirs fracture evaluation is a challenge in terms of type, density, aperture and extension. Borehole image logs, Stoneley permeability analysis, acoustic fracture ID and azimuthal shear-wave anisotropy evaluation from cross-dipole are key technologies in this context. They allow identification of individual fractures and provide information on fracture type, orientation, distribution (fracture density), aperture, permeability and extension. However, the meaning of features observed on image logs is a matter of interpretation at the borehole wall only. This introduces a degree of uncertainty, which may be greatly reduced by integrating other acquired measurements such as acoustic logs, which map the near borehole environment for fractures as well as their extension nature far away from the borehole. Therefore, integration of the two sources of information significantly enhances the benefits of both. While this principle is not new, technological advances in tool design and analysis software capabilities continuously expands the amount of detail that can be obtained.