CONDITIONS OF FORMATION, SEDIMENTATION CYCLICITY AND MODELS OF VOIDNESS OF FAMENNIAN DEPOSITS OF THE YUGOMASHEVSKOYE FIELD OF THE REPUBLIC OF BASHKORTOSTAN
A.S. Dushin, T.V. Burikova, D.S. Tarnovetsky
1Ufa State Petroleum Technological University, Ufa, Russia
2OOO RN-BashNIPIneft, Ufa, Russia
Keywords: carbonate structures, Famennian stage, facies, cyclicity, sedimentogenesis, secondary transformations, porosity, fracturing, leaching, Yugomashevskoye field
Abstract
The article summarizes new data on core and geophysical studies of wells of Famennian deposits in the Yugomashevskoe field located in the Republic of Bashkortostan (Russian Federation). Structurally, the object under consideration belongs to the model of a rimmeded platform with its characteristic elements—organogenic structures and associated facies. The identified sedimentation cyclicity and secondary processes, combined with an analysis of changes in relative sea level, made it possible to identify the most common types of porosity confined to one or another part of the section and facies zonation. Transgressive and regressive parts of the cycles are characterized by their specific set of lithotypes and characteristic types of void space. It was revealed that the formation of void space was influenced by the duration and intensity of secondary processes: leaching, dolomitization, claying associated with the removal of rocks to the surface. In addition, the work substantiates the division of carbonate structures of the study area into three types, differing in position, morphology, as well as in the different manifestations of hupergene transformations, which is reflected in the differentiation of the types of void space of the rocks compose them and their potential in terms of reservoir properties.
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