Realizing complex carbonate facies, diagenetic and fracture properties with standard reservoir modelling software

Abstract

Geocellular modelling of diagenetically altered carbonates is challenging as geometries and pore systems often appear irregular. It has long been recognised, however, that tectonic evolution forms a framework that can influence patterns of carbonate facies, diagenesis and fracturing, the combination of which determines reservoir geometries and properties. Unravelling these processes can reveal trends that were not evident from well data alone. Such trends are useful in building geocellular models that extrapolate reservoir properties along them and can be used for economic screening of undrilled areas. This paper shows how standard reservoir modelling software can be used to model complex geology. In particular, it is shown how a carbonate reservoir model was constructed based on concepts of facies, burial diagenesis, hydrocarbon charge and fracturing. Workflows are discussed that were employed to distribute reservoir properties related to these processes.

Fundamental controls on flow in carbonates: an introduction

“…(e.g. Pöppelreiter et al 2008). Consequently, it is common practice to preselect a subset of these heterogeneities as the focus of reservoir modelling studies based on interpretation of sparse subsurface data, an approach that is susceptible to a priori assumptions and personal bias.…”

A geocellular modelling workflow for partially dolomitized remobilized carbonates: An example from the Hammam Faraun Fault block, Gulf of Suez, Egypt

“…In carbonate reservoirs, there is significantly less data available to describe sedimentary body geometry. Carbonate reservoirs are heterogeneous and complex, owing to the changes in depositional systems through determined by what components of the carbonate factory are present or absent (Pomar and Hallock, 2008) and diagenetic overprinting, which influence the physical rock properties of carbonate faciesand fracture abundance (Sharp et al, 2006;Pöppelreiter et al, 2008;Pyrcz and Deutsch, 2014). In deepwater carbonate systems, further complexity is introduced by the sparse database of mass carbonate transport facies may be due to lack of study, and almost certainly to the difficulty associated with prediction, imaging, and modelling complex carbonate facies in outcrop and in seismici.e.…”

“…This is a grand challenge of carbonate reservoir modelling and has been approached in many different ways, including 1) modification of model properties to account for observed patterns of fluid flow (e.g. by use of permeability multipliers, or modification of K v /K h ) (Gomes et al, 2018), 2) petrophysical rock typing (Hollis et al, 2010;Skalinski and Kenter, 2014;Ghadami et al, 2015;Fu et al, 2018) or 3) building diagenetic overlays and/or fracture overlays to merge with the sedimentological model of rock properties (Pöppelreiter et al, 2008;Sharp et al, 2010). Option 1 is efficient and might permit history mapping, but has no geological constraint and therefore could lead to inaccurate forecasting.…”

“…In totality, carbonate depositional facies, diagenesis, and fracture networks are all heavily influenced by sedimentological processes and the tectonic evolution of the basin in which they were deposited (Pöppelreiter et al, 2008). Although this statement is widely accepted to be true, it is not common to find modelling workflows that directly acknowledge the importance of basin evolution on sedimentary and reservoir architecture; ie.…”

Coupling fracture facies with in-situ permeability measurements to generate stochastic simulations of tight carbonate aquifer properties: Example from the Lower Cretaceous aquifer, Northern Provence, SE France

“…Here to better account for structural and petrophysical heterogeneities we use a three-dimensional model to represent the reservoir architecture, including stratigraphic surfaces and faults, to describe the Lower Cretaceous limestone aquifer in Northern Provence. Our pixel-based stochastic method, such as the one used in sedimentary facies simulation, is seldom considered to model faults and fractures in reservoirs [14,15]. These methods require generating a large number of equiprobable models to be reliable, which is time consuming and requires high performance software.…”