What do we really understand about pore systems in carbonates?

The construction of 3D reservoir models that are capable of confidently predicting flow behaviour in carbonate reservoirs requires that the porosity distribution in the reservoir is characterised appropriately and related to a robust conceptual geological model. Porosity is at the root of both reservoir characterisation and reservoir modelling, but its measurement and description remains an area of uncertainty since in many fields there is a discrepancy between core and log derived reservoir properties. In addition, robust conceptual models to predict reservoir properties in the interwell area of carbonate reservoirs are often weak. This largely reflects an immaturity in the tools available to predict the effects of diagenesis on porosity. The aim of this paper is to establish a picture as to where we currently stand with regard to the characterisation of carbonate pore systems and identify emerging technologies that will improve confidence in future models. The case is made here for a genuinely interdisciplinary approach to reservoir characterisation, but also for a return to truly geological models to increase confidence in the predictive capacity of 3D reservoir models. Central to this is a recommendation to more consistently consider the diagenetic process responsible for porosity development.