Recent Advances in Forward Stratigraphic Modeling of Giant Carbonate Reservoirs and Evaporite Systems

Abstract

This communication discusses the return of experience on the latest innovation in carbonate and evaporites modeling using deterministic diffusion based forward stratigraphic modeling approaches and sensitivity analysis. The depiction of carbonate and evaporite heterogeneities in reservoir models remains a major challenge as traditional stochastic techniques appear to be insufficient in capturing vertical and lateral facies/texture variability. Carbonate and evaporite systems are intrinsically linked to the depositional realm under which several environmental parameters interact to generate/or destroy optimal conditions for the thriving of such sensitive ecological systems (e.g. bathymetry, wave energy, lighting conditions, precipitation versus evaporation). Throughout recent studies (e.g., Abu Dhabi, Suez Rift, Kuwait, Saudi Arabia), a multi-scale naturalistic approach was developed using DionisosFlow forward stratigraphic modeling and CougarFlow sensitivity analysis tools. The workflow tackles the several limitations of stochastic methodologies by (1) achieving a multi-disciplinary data integration, (2) accounting for the evolution of geological processes with time, (3) representing complex carbonate geometries (algal mounds, reefs, aggradation, progradation, clinoforms), (4) assessing the sensitivity of the proposed geological model with regards to environmental conditions and finally by (5) generating multiple plausible geological scenarios and facies probability/risk grids. High resolution forward stratigraphic reference-case models are manually calibrated to well and seismic data (2D, 3D, seismic inversion and characterization) by multiple loops of environmental parameters adjustments. Automated multi-realizations using a Latin-hypercube experimental design measure the impact of varying uncertain environmental parameters on sediment texture/facies and thickness (e.g., carbonate production rates, carbonate factories, wave parameters, water salinity, precipitation versus evaporation, eustasy, erosion rates, transport parameters). The mapping of carbonates and evaporites using this coupled process based forward stratigraphic and multi-realization approach could also lead to a qualitative risk assessment of early diagenesis through the combined understanding of depositional environment, vertical and lateral lithologies/texture variations, sedimentation rates and residence time amongst other influencing factors.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017