Prospective Carbonate Neocomian Trends (Makhul, Minagish and Ratawi Formations) in Southwest Kuwait

Neocomian strata (Makhul, Minagish and Ratawi Formations) of southwest Kuwait were studied to evaluate additional exploratory opportunities. Cores, well logs and reports from over 50 key wells were used to identify stratigraphic trends and refine play concepts. Stratigraphic analysis and mapping resulted in better understanding of stratigraphic context and paleogeographic distribution of potential reservoirs.

Neocomian strata in Kuwait are interpreted as sequence comprised of a TST represented by the Makhul Formation and an HST represented by the Minagish and Ratawi formations (Sharland et al., 2001). In this study, these strata are interpreted as multiple seaward-stepping cycles. The Makhul Formation represents a four-part asymmetric cycle, the lower three cycles stepping seaward and the upper cycle stepping landward. The Minagish formation conformably overlies the Makhul Formation and is interpreted as a two-part asymmetric cycle, the lower fall hemicycle stepping landward and the upper rise hemicycle stepping seaward. Finally, the Ratawi Formation constitutes a two-part fall asymmetric cycle where the Ratawi Limestone cycle steps seaward and is overlain by a more “clastic” cycle which also steps seaward.

Using regional mapping, this study updated previous work and identified the following stratigraphic and paleodepositional trends that may control the distribution of reservoirs. The Makhul Formation changes facies from higher energy conditions in the SW to lower energy conditions in the NE (i.e. Midde ramp - inner ramp to outer ramp). The Minagish Formation shows oolitic facies only at the Rugei, Minagish, Abdaliyah and Umm-Gudair fields. Facies change toward lower energy conditions from SW to NE. Finally, The Ratawi Formation changes from higher to lower energy facies from SW to NE.

Paleogeographic mapping of the Ratawi Shale member revealed an important reentrant feature. This feature is characterized by the presence of shaly facies located at the Minagish and Umm-Gudair fields which are surrounded by sandy facies at the Rugei and Dharif Fields.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California