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Kudamanov A.I.
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aikudamanov@tnnc.rosneft.ru |
“Tyumen petroleum research center” LLC Tyumen |
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Pavlutkin I.G.
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“Tyumen petroleum research center” LLC Tyumen |
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Karikh T.M.
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“Tyumen petroleum research center” LLC Tyumen |
DOI: 10.24412/2076-6785-2023-8-62-69
Abstract
The Upper Cretaceous (Santonian) opokas within the West Siberian Plate (WSP), developed over an area of more than two million square kilometers in the form of a reservoir 30–35 m thick are characterized by an uneven degree of crystallization of the opal-crystobalite-tridymite (OCT) phase of silica. According to X-ray diffraction (XRD) analysis, across much of the WSP, the content of secondary quartz ranges from the first units to 30–40 %.
Occasionally (in the west and south-west), secondary quartz makes up more than 70 %, while the OCT phase has not been detected
by XRD (complete crystallization). Morphological differences in silica segregations were interpreted in SEM (Scanning Electron Microscope) images magnified 5–6 thousand times.
Magnification of 5–6 thousand times allows to identify signs of varying degrees of crystallization of amorphous silica.
Materials and methods
The results of a comparative analysis of laboratory data (X-ray diffraction, petrographic method, and scanning electron microscopy) on the Upper Cretaceous (Santonian) opokas in West Siberia, characterized by laterally irregular degrees of crystallization of amorphous silica. When magnified by more than 5 thousand times, morphological differences of silica units with varying degrees of crystallization were established.
Keywords
berezovsky formation, opokas, colloid, lepispheres, crystallization
