Unlocking the Remaning Potential of the Thayem and Nishan Fields from Outcrop and Core Studies, Syria

Al-Ja’Aidi, Omar¹, Peter Homewood¹, Henk Droste¹, Jamal Al Jundi², Mohammed Abou Shaker², Jurgen Grotsch² (1) Sultan Qaboos University, Al Khod, Oman (2) Al Furat Oil Company, Damascus, Syria

The Thayyem and Al Nishan oil fields are located in north-eastern Syria, where commer­cial quantities of oil were discovered in the 1980s. However, since 1991 production from these fields has been declining. An integrated core and outcrop study was carried out on the Lower Miocene Dhiban Formation in order to develop a depositional model, which in turn would lead to a better understanding of the facies distribution and reservoir quality within these fields.

Outcrop and core studies indicate that the transgressive and regressive part of the Dhiban Formation are each characterized by different facies associations and two deposi­tional models are required to describe this interval.

The transgressive interval is dominated by moderate energy, good reservoir quality sub­tidal mollusk sands and littoral deposits closely associated with supra-tidal sabkha. This may suggest the presence of a poorly developed protective barrier and that the inter-tidal and sub-tidal environments may have been isolated by growth of beach bars and spits. In core, the regressive unit displays a more restricted facies association of thick oil stained stromatolites, salina, muds and marls and supra-tidal sabkha. Here the protective barrier is better developed with a low energy inter- to sub-tidal area between the barrier and the supra­tidal sabkha.

The two depositional models have different implications for the lateral continuity and stacking trends of the reservoir and sealing intervals.