The majority of oil fields discovered in carbonates reservoirs are controlled by single and barrier organic buildups located in starved basins. Within the Republic of Bashkortostan new highly promising exploration areas can be identified through the study and analysis of trends and patterns in the development of reefs. Reefs and bioherms tend to both accumulate oil and gas and form draping structures for trapping hydrocarbons in the overlying deposits. Currently such build-ups are underexplored. In the case of 2D seismic lines are usually too sparse for identification and mapping of all such features hence additional thorough investigation of the regional geology is required before an exploration program can be formed with new recommendations.
The study presents the updated conceptual depositional model of the Late Frasnian to the Late Tournaisian. The analysis reveals the causes of carbonate sedimentation and formation of build-ups as well as trends in their development. The distribution of oil deposits controlled by organogenic buildups has been analyzed. Within the South-Tatar and Bashkir uplifts patterns of the distribution of organic buildups are noted. An analysis of the conditions of sedimentary cover formation in the Late Devonian era allowed us to determine the area of mass distribution of reefs and bioherms, as well as to identify unfavorable zones for the existence of carbonate buildups. The understanding of the patterns in the regional development of carbonate build-ups over time, their correlation with reservoirs and seals is useful in identification of new licensing and seismic exploration opportunities. It is also important while choosing oil deposits for drilling and refilling the hydrocarbon resource base.
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