Variability of Jurassic Hydrocarbon Plays and Controls on Their Prospectivity in Kuwait

Abstract

The Jurassic formations constitute one of the most important established petroleum system of the State of Kuwait. This petroleum system encompasses multiple source, reservoir and seal intervals and several producing fields spread all over Kuwait. Middle Marrat, Sargelu and Najmah are the prolific producers of oil, condensate and gas while Lower Marrat, Upper Marrat, Gotnia, Hith and Basal Makhul are emerging as potential reservoirs for focused exploration. These strata are characterised by a complex depositional, diagenetic and tectonic history introducing an element of uncertainty in assessment of their hydrocarbon potential and necessitating a clear understanding of their impact on hydrocarbon entrapment. Marrat, Sargelu, and Middle Najmah plays are conventional matrix porosity supported plays. There is a strong primary depositional facies control on porosity and diagenesis significantly impacts permeability distribution. The gross depositional environments, diagenetic history and shift of potential reservoir facies in response to relative sea level changes are linked to shift in prospective locales and provide a predictive tool for identification of prospective areas. The Lower Najmah and the Basal Makhul Shale represent unconventional shale hydrocarbon plays. The Lower Najmah play is prospective for oil in southern part and for condensate and gas in northern and western parts of Kuwait, while the Basal Makhul play is prospective for oil. Prospectivity of these shale plays is mainly dependent on occurrence of natural fractures, organic richness and maturation. Gotnia and Hith formations, hitherto considered as regional seals, are potential tight plays. These formations have organic rich carbonates encased within anhydrite. Their hydrocarbon potential depends on depositional facies, natural fractures and vicinity to migration conduits linking the reservoirs to the source intervals. In view of diverse controls on prospectivity of the reservoirs, customized layer-specific workflows are the pre-requisites for effective future exploration of Jurassic resources.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015