David A. Wavrek¹, Daniel D. Schelling², Dimir Mirzoyev³, Zilfikar Dashtiyev⁴, Dimitri Shlygin⁵

(1) Petroleum Systems International, Inc, Salt Lake City, UT
(2) Structural Geology International, Salt Lake City, UT
(3) Dagestan Science Center, Russian Academy of Sciences, Makhachkala, Dagestan, Russia
(4) Dagneft, Makhachkala, Dagestan, Russia
(5) Institute of Geological Sciences, Kazakh Academy of Sciences, Almaty, Kazakhstan

ABSTRACT: Structural Control of Central Caspian Petroleum Systems: Dagestan and Kazakhstan

The hydrocarbon charge in the Central Caspian region is generated from Upper Triassic-Lower Jurassic, Middle Jurassic, and Oligocene-Miocene source rocks. The Mesozoic source rocks are restricted to extensional basin troughs, whereas those of the Tertiary are more regional. Subsequent compressional and/or transpressional deformation had a strong influence on the orientation of migration pathways for hydrocarbon charge into the resultant structural traps, as illustrated in each hydrocarbon province. The Dagestan fold-belt hanging wall anticline structural traps are charged with hydrocarbons sourced from the Oligocene-Miocene source rocks through migration pathways facilitated by thrust faults and fracture systems. The Terek-Caspian foredeep traps are charged from Triassic-Jurassic source rocks within the Permo-Triassic East Manych trough, and migration occurs upsection along relatively young fault and fracture systems that developed as a result of thrust loading to the south. The hydrocarbon charge for structures in the Mangyshlak basin is correlated to similar Triassic-Jurassic source rocks that formed in the southward deepening half-graben. These hydrocarbons accumulate within folds on the northern margin as a result of early (?) Miocene south-vergent compressional deformation along its northern flank as a result of tectonic inversion and transpressional reactivation along a north-dipping normal fault. Understanding the petroleum systems of the hydrocarbon provinces of Dagestan and Western Kazakhstan will be critical to reducing exploration risk in the relatively unexplored Central Caspian Sea.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado