3D forward stratigraphic modelling of the Lower Jurassic carbonate systems of Kuwait

Abstract

This paper describes the architectural and texture/facies evolution of a complex carbonate system through the construction of a regional scale 3D stratigraphic forward model (252 × 152 km2, 4 km × 4 km grid size) encompassing onshore and offshore Kuwait. The model mimics the development of a Jurassic carbonate ramp system at a 2nd to 3rd sequence stratigraphic order (1–80 Myr duration; Schlager, 2010) by simulating sedimentary processes and ecological parameters such as carbonate production versus depth, time, wave energy, as well as erosional and gravitational transport. Multi-scale 1D, 2D, and 3D geological and geophysical constraints have been used to calibrate the Lower Jurassic Marrat stratigraphic model, which resulted in the identification of (1) a dominantly transgressive lower unit composed of onlapping packages of mudstone to wackestone textures, with anhydritic intercalations; (2) a dominantly regressive middle unit composed of prograding inner ramp shoal and lagoonal facies with wackestone to grainstone textures, and finally (3) a transgressive onlapping upper unit composed of mudstones to wackestones textures in a mid-ramp system. The identification of potential reservoir facies like oncolitic shoals located onshore Kuwait, as well as possible porous reworked material transported away from the shoal loci in a relatively deeper mid ramp settings provides a better insight on further model improvement needed to de-risk stratigraphic trapping mechanisms. The identification of porous features in 3D provides crucial insights on the influence of ecological constraints on the complex Jurassic carbonate ramp systems of Arabia.