Home – Home – Jornals – Russian Geology and Geophysics 2001 number 11-12

This paper deals with the structure and genesis of the Talakh, Khamakin, and Botuobiyan Horizons of the Chayandinskoe oil and gas condensate field, located on the north-eastern slope of the Nepa-Peledui dome of the Nepa-Botuobiyan anteclise. It is shown that the models for these horizons are dip-lenticular rather than plane-parallel. The producing horizons are characterized by significant lateral and vertical inhomogeneity related to the sedimentation conditions. The deposits formed in the setting of sea coast, which evolved from rock-type coast with the strongly dissected relief of the sea bottom (Talakh Horizon), gradually acquiring geomorphologic elements typical of open sea coast. This evolution provided a set of facies making up the producing horizons: The Talakh Horizon is dominated by the turbidite facies; the Khamakin Horizon, by the facies of the cis-frontal zone of the beach; and the Botuobiya Horizon, by the facies of the beach and its cis-frontal zone. The lateral and vertical inhomogeneity intensifies in the horizon sequence: Botuobiyan-Khamakin-Talakh.