Vladimir Petrovich Morozov

Petrographic analysis of thin sections of terrigenous rocks plays a key role in characterizing reservoir properties, enabling the assessment of textural and structural features as well as porosity—essential for reconstructing depositional environments and post-sedimentary alterations. Conventional manual analysis of thin sections is time-consuming and subjective, necessitating its automation. This study proposes an automated method for analyzing thin-section areas of quartz sandstone with carbonate cement based on deep learning, combining instance segmentation using the Mask R-CNN model with semantic segmentation employing SemanticFPN. This ensemble approach achieves high segmentation accuracy, as confirmed by Pixel Accuracy and Intersection over Union metrics, significantly accelerating petrographic data processing while enhancing objectivity and reproducibility. The method holds practical value for geological and petroleum exploration studies.

The work studied the lithological and geochemical characteristics of oil and gas source rocks of the central part of the Volga-Ural oil and gas bearing province. The purpose of the work was to reconstruct their formation conditions, study the generation potential and maturity of organic matter, and examine prospects for industrial development. The rocks were studied macroscopically, as well as X-ray analysis, pyrolysis using the Rock-Eval method, SARA analysis, and gas chromatography-mass spectrometry. The formation of the Domanik deposits, Bobrikovsky and Pashiysky horizon mudstones, and Upper Kazan substage clays have all been proven to have occurred in a maritime environment. The content of organic matter in the rocks varies from 0.35 to 11.16%. Minute amounts of organic matter that are difficult to accurately in terms of their geochemical properties can be found in the clayey deposits of the Vereisky and Timan horizons. The Upper Kazan substage clays contain type II/ III kerogen. Mudstones of the Bobrikovsky and Pashiysky horizons, as well as Domanik deposits, contain organic matter represented by type II kerogen. The data obtained may indicate common mechanisms for the accumulation of sapropelic organic matter on the territory of the Volga-Ural basin from Pashian (Frasnian stage) to Bobrikovian (Visean stage) times. It was revealed that the studied deposits are at the stage of catagenesis (PC-MK1). At the same time, Domanik deposits have very good and excellent generation potential, which is characterized by the greatest maturity. Mudstones of the Bobrikovsky horizon have similar generation potential.

We provide a brief description of two editions by Professor Vitaly Germanovich Kuznetsov, Gubkin Russian State University of Oil and Gas. These include the textbooks “Lithology” and “Sedimentary rocks and methods for their analysis”, which present particular interest in the context of the lack of educational materials on lithology. The reviewed textbooks will be helpful for geology students mastering lithological disciplines and preparing for graduate examinations in discipline 1.6.5. Lithology.

In this research, we used a combination of available data (core analysis and borehole image logs) to characterize the Judea Formation sediment fractures. The Judea Formation low-energy marine shelf sediments are made up of limestone in the upper half and dolostone in the lower. Some induced and enhanced fractures with an N-S striking direction were identified using FMI image logs. Furthermore, the rock naturally fractures with an NNE striking orientation. The characterization of fractures using core studies revealed that the limestone zone had a greater quantity of induced fractures than the dolomite zone. Within the dolomite zone, naturally occurring fractures are frequent; they are open or partially filled with secondary mineralization. Due to the breaking of the limestone matrix under compression during burial diagenesis, sealed fractures with calcite are primarily recognized in the limestone zone. Due to the plastic deformation/pressure solution of the soft carbonate host rocks, sealed fractures with clay are most prevalent in the limestone zone. Because of their link with the dolomitization that floated over the lower part of the Judea Formation section during diagenesis, sealed fractures with dolomite were primarily identified in the dolomite zone. As a result of the significant dolomitization, sealed fractures containing bitumen formed within the dolomite zone conduits, serving as hydrocarbon migration pathways. The paragenetic sequence is given, although it is stressed that many parts are still hypothetical owing to the inadequate database. Geological and/or other projects in the Euphrates Graben area can use help from such an integrated study.

It was studied the composition of salt-forming brines, the composition of insoluble salt residue and the sedimentation environment for the Upper Pechora evaporate basin at the halite crystallization stage in the underlying rock salt layer (Lower Permian, Kungur). The results are obtained from studying individual inclusions in halite, chemical composition of primary fluid inclusions brines, the phase composition of salts, and the homogenization temperatures of single-phase liquid inclusions in halite, by their preliminary cooling. The obtained data possible to establish the accumulation of the salt strata of the Upper Pechora potassium-magnesiums basin in shallow-water depositional environments. The brines of the basin belonged to sulfate tipe of the ocean water. The concentration of brines during the crystallization in the underlying rock salt layer was close to the stage of potassium minerals precipitation.