Geochemical Trends Reflecting Hydrocarbon Generation, Migration and Accumulation in Unconventional Reservoirs Based on Pyrolysis Data (on the Example of the Bazhenov Formation)

Abstract

The current study is devoted to the determination and interpretation of geochemical trends reflecting hydrocarbon generation, migration and accumulation in unconventional reservoirs; the study is performed on the Bazhenov shale rock formation (Western Siberia, Russia). Results are based on more than 3000 Rock-Eval analyses of the samples from 34 wells drilled in the central part of the West Siberian petroleum basin, which is characterized by common marine sedimentation environments. Pyrolysis studies were carried out before and after the extraction of rocks by organic solvent. As a result, we have improved the accuracy of kerogen content and maturity determination and complemented the standard set of pyrolysis parameters with the content of heavy fraction of hydrocarbons. The data obtained for the wells from areas of different organic matter maturity was summarized in the form of cross-plots and diagrams reflecting geochemical evolution of the source rocks from the beginning to the end of the oil window. Interpretation of the obtained results revealed quantitative trends in the changes of generation potential, amount, and composition of generated hydrocarbons in rocks at different stages of oil generation process. The analysis of geochemical trends allowed us to improve approaches for the productivity evaluation of the formation and study the effect of organic matter maturity on distribution of productive intervals of different types.

Rock–Fluid Interactions of Alkyl Ether Carboxylate Surfactants with Carbonates: Wettability Alteration, ζ-Potential, and Adsorption

“…The output RE pyrolysis parameters were S0, S1, and S2 peaks measured in mg-HC/g-rock according to the temperature output. S0 peak corresponds to gaseous hydrocarbons (100 °C), S1 to free oil (liquid hydrocarbons) (300 °C), and the S2 peak was formed by HC of kerogen cracking in the case of source rock or heavy oil components (including paraffins, resins, and asphaltenes) in the reservoirs or unconventional resources. − Each sample was analyzed at least twice. In this work, a Rock-Eval pyrolysis technique was proposed for the qualitative characterization of the rock wettability change and description of the surfactants’ mechanism of action.…”

Provenance and the U–Pb age constraints on the tuff beds of the Late Jurassic–Early Cretaceous Bazhenovo Formation, West Siberian Basin

“…The precursors of this organic matter were predominantly algae and bacteria. The organic matter in the Bazhenovo Formation is commonly classified as type II kerogen with a minor contribution from type I kerogen (Bulatov et al., 2022; Goncharov et al., 2021; Spasennykh et al., 2021).…”

Uranium in Source Rocks: Role of Redox Conditions and Correlation with Productivity in the Example of the Bazhenov Formation

“…In the current study, we analyzed uranium concentration, the content and composition of organic matter in the Bazhenov Formation rocks from 13 wells located in the central and northern parts of the Basin (Figure 1). The BF deposits of the studied wells are identical in terms of lithological composition and initial OM content, but demonstrate different degrees of maturation (catagenetic transformation) [26]. [27]) with location of studied wells and stratigraphic column.…”