Often considered as a complex task, rock-typing in carbonates comes down to achieve reconciliation between various sources of data, including high resolution logs, representative core data and dynamic data.
The simplest statistical relationship between petrophysical classes and geological facies should be sought for.
More than 30 years of experience in carbonate fields has reinforced TOTAL's expertise leading to a specific rock-typing workflow through upscaling management of all available information from pore to plug, plug to core, core to log and log to model grid-cell.
This paper details the 8 main steps of a Rock-Typing workflow which is indifferently supported by in-house or commercial softwares.
The main Rock-Typing studies objective is to contribute to build a predictive dynamic model by an accurate 3D-distribution of geological facies being petrophysically meaningful through porosity, permeability, Pc and Kr.
To achieve this point, petrophysical properties have to rely on 3D-predictive variables (such as Geological Facies) depending on a quantification of statistical correspondances between Geological Facies (including sedimentological and diagenetical patterns) and Petrophysical Groups (rock units with homogeneous petrophysical behavior).
Carbonates rocks require a specific approach compared to clastic ones due to a higher level of complexity (facies heterogeneity, early and/or late diagenesis, pore topology, wettability changes).
A specific workflow based on 30 years of experience on world wide carbonate reservoirs has been developed, supported by in-house or commercial softwares. As a result of more than 10 years of R&D effort on sedimentology, diagenesis and petrophysical synthesis, relying on numerous case studies (REBELLE et al., 2000; REBELLE & AL NUAIMI, 2004; REBELLE et al., 2005; REBELLE & UMBHAUER, 2008; UMBHAUER et al., 2008), this resulting workflow reflects an integrated approach of different specialities as illustrated on Figure 1.