Concentric Saturation Maps for Carbonate Heterogeneity at the Wellbore Scale

The carbonates of the Pinnacle Reefs offshore Malaysia are known to be a complex mixture of depositional and diagenetic fabrics. Information on these fabrics is sometimes sparse due to limited borehole logging as a result of partial or total losses. A technique has been developed to help quantify the radial variations by using azimuthal LWD measurements. The combination of multi-directional density and resistivity measurements (the latter also at multiple depths of investigation) allows concentric heterogeneity maps to be built at each depth level. These are based on saturation by combining the azimuthal density porosity and resistivity measurements. In the three wells analysed, distinct variations in heterogeneity are observed around and along the boreholes. In places these can be directly related to local dolomitisation.