Refinement of the subsalt formation model: eastern flank of the Caspian basin
The paper considers structural and tectonic characteristics of regional tectonic elements within the Palaeozoic subsalt series. The authors carried out zoning within the eastern shoulder of the Caspian Basin (Zhanazol‑Tortko’lsky, Temirsky, Shubarkuduk‑Koskol’sky zone of uplifts, Borzher‑Akzharsky Flat, etc.). The concept of regional features of Palaeozoic formations architecture and spatial distribution of carbonate KT‑II and KT‑I sequences is presented. The authors’ version of interpretati on of carbonate sequences occurrence is proposed, which is based on the new data. It is shown that in the course of carbonate sequences tracking and prediction, their regional erosive pinching‑out and lithological thinning is observed westward from the basin shoulder, which is indicative of their origin and evolution associated with a platform. These conditions together with limitation of the formations westward strike are established in the E‑W‑trending belt of Zhanazol, Kozhasai, Urikhtau structures. Similar situation is expected in the belt of Akkuduk, Baktygaryn, Akkum, Akkemir structures within the western edge of the promising Temirsky zone of uplifts. Positi on of the promising traps within KT‑II and KT‑I formations is updated; the possibility to scale out prospecting on the result of the carbonate КТ‑III formation (Upper Devonian – Lower Carboniferous) prediction is emphasized. The obtained conclusions and recommendations are aimed at improvement of prospecting activities efficiency and further works taking into account the correction of methodology used for studies and prediction of promising traps in the Carboniferous formations within the Caspian Basin eastern shoulder, and clarification of great prospects of the Zhanazol‑Tortko’lsky and Temirsky zones of uplifts.
Key words: Caspian basin; deposits; eastern flank; Palaeozoic series; carbonate sequence; zone of uplift; petroleum potential; explorati on works; local objects; hydrocarbons.
For citation: Azhgaliyev D.K. Refinement of the subsalt formation model: eastern flank of the Caspian basin. Geologiya nefti i gaza. 2019;(6):31–40. DOI: 10.31087/0016‑7894‑2019‑6‑31‑40.
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