Abstract

V. Yu. Kerimov, G. N. Gordadze, R. N. Mustaevand A. V. Bondarev

DOI : http://dx.doi.org/10.13005/ojc/340243

The article is a study of the formation conditions and distribution patterns of generation and accumulation hydrocarbon systems (GAHS) on the Sakhalin shelf of the Sea of Okhotsk. A complex of geochemical studies was conducted for the evaluation of oil and gas source rocks generative capabilities and for the study of the organic matter geochemical parameters. The study included the determination of total organic carbon (TOC) in rocks, pyrolysis by Rock-Eval method, parameters (S1, S2, Tmax, HI, PI); bitumoid extraction from rock with subsequent determination of its group composition. Analysis of oil geochemical parameters by hydrocarbons-biomarkers for the purpose of determination genetic unity and maturity level of oil and gas source sequences was conducted. Using the method of capillary gas-liquid chromatography (GZhC), the analysis of n-alkanes and isoprenanes in paraffin-cycloparaffin (PCP) oil fractions was conducted. Method of chromato-mass spectrometry (ChMS) was utilized for a study of high-molecular hydrocarbons -biomarkers (steranes and terpanes). It was implemented using computer data processing under SIM regime with the recording ions m/z 217, 218 for steranes and diasteranes, m/z 191, 177 for terpanes. The separation of hydrocarbon organic matter was conducted in a capillary column with silicone phase HP-1ms. Chromatographing was implemented under temperature linear programming regime between 70 and 290оС at the rate of temperature increase 4о/min. The carrier gas was helium. The study of geochemical parameters in the Paleogene-Neogene sediment complex indicates a sufficiently high Corg content and its concentration increases down the section. Organic matter type in the sedimentary section often changes from humic to humic-sapropelic, the dominating type is humic (III). GAHS, elements and processes of these natural systems were modeled for the study of the formation environment and distribution patterns of generative – accumulative hydrocarbon systems and HC generation foci and their energy resources on the Sakhalin shelf in the Sea of Okhotsk utilizing techniques of basin modeling and PetroMod (Schlumberger) software. Based on modeling results, 6 independent generation foci of oil and gas were identified on the Sakhalin shelf. Each of them could have independently generated hydrocarbon fluids for saturating nearby traps.

Geochemical Research; Pyrolysis; Generation; Hydrocarbons-Biomarkers; Organic Matter; Hydrocarbon Systems; The Sea of Okhotsk; Modeling

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