Low Resistivity Pay in Carbonate Rocks and Variable m


Philip Bateman, Chevron Canada Resources


Historically, in the Swan Hills Formation of Central and Western Alberta, it was often assumed that if the resistivities on an induction log were not off scale, the well would produce water, par ticularly if it was one of the deeper dolomite reservoirs. In recent years we have seen several examples that challenge our understanding of pore geometry and `m’. Examples of diverse porosity-resistivity rela- tionships are shown for the Karr-Simonette-Kaybob area. A cross- plotting technique is shown, where the ratio between neutron-densi- ty crossplotted porosity and neutron-sonic crossplotted porosities helps "type" the reservoir and gives a potential range of `m’.