Carbonate Rock Type Identification Using Pore Throat Size Distribution Clusters

Abstract

Summary In this study, the examples of pore throat size distribution (PSD) clusters/classes derived from Mercury injection capillary pressure (MICP) data as rock type identifier are shown on different carbonate reservoirs as the first step in a systematic rock typing workflow. The identified rock types are also called petrophysical rock types (PRTs) by Thomeer (1983) possessing a cluster or continuum in the parameter space related to petrophysical attributes such entry pressure corresponding to the largest pore throats, the distribution of the pore throats and total amount of porosity which can be extracted from MICP analysis as well as permeability. More than 400 MICP data were analysed, where the clusters of the derived PSDs are compared against porosity/permeability grouping for the corresponding core plugs. In this study, it is shown how PSDs or Thomeer hyperbola’s parameters grouping can be useful to identify the number of rock types/PRTs for carbonate reservoir characterisation. A good agreement between porosity/permeability grouping and clustering of either PSDs or Thomeer hyperbola’s parameters are also observed.