Facies analysis of Aptian quartz sands using the example of the Stebaevskoye field (Lipetsk region)

Abstract

Introduction: quartz and glass sands are a valuable resource widely used in industry. In the northeastern Voronezh anteclise, the potential for discovering large deposits of glass and construction sands is associated with deposits of the Volchinskaya and Devitskaya formations of the Aptian stage, Miocene (Putudanskaya series), and Upper Pliocene (Goryanskaya series). The Aptian formations are of greatest interest.

Characteristics and geological structure of the study site: The Stebaevskoye construction sand deposit was selected as a model study site. The useful medium-grain sand sequence is confined to the lower sub-sequence of the Devitskaya Formation of the Lower Cretaceous, while the fine-grain sand corresponds to the upper part of the Volchinskaya Formation of the Lower Cretaceous. Three facies are distinguished at the deposit from bottom to top: 1 – coastal-marine facies of white, fine-grained sands of the Volchinskaya Formation, consistent in grain size distribution; 2 – deltaic facies of cross-bedded, inequigranular sands of the Devitskaya Formation, filling the bed of a buried paleo-river; 3 – proluvial-alluvial, bright orange, highly clayey, substandard sands and sandy loams.

Facies analysis: to study the hydrodynamic activity of the sedimentation environment, the results obtained during drilling and laboratory work were applied to a map. The average fineness modulus of sand for each studied well was used as the main parameter for constructing the facies model. The Arcgis software package's 3D Analyst module was used to plot the color dependence, where the dynamics of fineness modulus change were determined in plan view. To study the pattern of fineness modulus change in the cross-section, a scatter plot of fineness modulus versus well core sampling depth was used. The study data indicate that coarse-medium-grained sands form in the channel facies, while fine-grained sands form in the coastal-marine facies.

Conclusion: to predict the discovery of deposits for construction and glass raw materials, the facies distribution of Aptian sedimentary deposits should be considered. Analysis of available data allows us to predict the Kruto-Khutorskaya, Studeno-Khutorskaya, and other promising areas to the northwest for the discovery of construction and glass sand deposits, confined to the paleovalley of an ancient river and the shallow-marine facies of the Aptian period, located close to the regional capital, Lipetsk, which are of interest for industrial development.