Sedimentological Interpretation and Hydrocarbon Potential of the Albian Mauddud Formation in Kuwait and Adjacent Areas

Abdullah, Fowzia H.¹, A.S. Alsharhan² (1) Kuwait University, Mishrif, Kuwait (2) Middle East Geological Enterprises, United Arab Emirates

The Albian Mauddud Formation is one of the major Cretaceous oil reservoirs in Kuwait. It composed of about 24-105 thick of carbonates and siliciclastics second order composite sequences. The carbonates mainly packstone/wackestone contains interbedded finely crys­talline dolomitic limestone and soft porous limestone. The siliciclastics is composed of fine, greenish-brown gluconitic sandstones mixed with shale and dark grey marls rich in micro­fossil and same pyrite. The Lower Mauddud transgressive sequence set shows lateral change in facies from more carbonate in the north to mixed siliciclastic/carbonate in the south. While the Upper Mauddud highstand sequence set is more carbonate-prone. Geochemical analysis shows that the formation has migrated oil mostly in the carbonate section with kerogen mainly in the shale parts. The kerogen show immature type II-III, with TOC ranges 0.64-3.8%. The organic matter is dominated by marine amorphous type with minor concentration of terrestrial particles. Porosity ranges 10-35% and permeability 10­1000 md.

In the Arabian Basin the formation represents a very shallow to shallow carbonate shelf with local basin margin rudist buildups that was established following the shutdown of the clastic front of the Nahr Umr/Burgan Formation. Extensive dolomitization, fractures and dis­solution of the grainstone/packstone facies of the formation are the main controlling factors that shaped its petrophysical characters. The formation is a major oil-producing reservoir in northern Iraq, Bahrain and Oman and has high oil potential in south and southeastern Iraq, northern offshore Qatar and northeast offshore Saudi Arabia.