Image Petrophysics - A New Approach to Evaluate Fractured Reservoirs
Bore hole imaging is the only tool to characterize from very small features like fractures up to major structural features.
Since the early 80’s, bore hole imaging based on resistivity measurements has been the only tool with the vertical resolution, capable to detect very small fractures as well as other structural features such as faults, unconformities or folds. The main question about this technology has been, how deep into the formation these small features really are?.
There are only a few methods to evaluate the fracture extension over the reservoirs, one is a dynamic interference test among two or wells, another is the use of seismic attributes and neural networks to correlate with image logs and/or core data. From the images the fracture orientation, spacing, aperture are obtained, which could be used to calculate fracture porosity and permeability around the well bore using image petrophysics, were each resistivity curve is transformed into a porosity and permeability curve generating an azimuthal property distribution defining the vertical and the horizontal anisotropy of each interval of the reservoir. Using this extremely powerful method and integrating with seismic attributes several wells were evaluated and integrated as part of 3D reservoir models, in fractured reservoirs.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009