ГАЗОГИДРАТЫ АЗЕРБАЙДЖАНСКОГО СЕКТОРА ЮЖНОГО КАСПИЯ: ТЕРМОДИНАМИКА, СЕЙСМОАКУСТИКА И ГАЗОПРОЯВЛЕНИЯ
Open Access
- 11 December 2018
- journal article
- research article
- Published by National Research Tomsk Polytechnic University in Bulletin of the Tomsk Polytechnic University Geo Assets Engineering
- Vol. 329 (12), 164-178
- https://doi.org/10.18799/24131830/2018/12/32
Abstract
Relevance. Geological structure and bathymetry of the seabed of the deep-water part of the Caspian Sea indicate the possibility of formation of significant amounts of gas hydrates. The analysis of the published and unpublished materials on Caspian gas hydrates has shown that basically all works are based only on study of Elm, Bozdag, Absheron gas hydrates accumulation, and thermodynamic factors of the region (without taking into account the actual values of temperature and pressure) in order to determine the possible zone of their accumulation. The aim of the research is to calculate the volume of hydrocarbon gases of gas hydrates according to thermodynamic data, as well as to study and predict the inflow of hydrocarbon gases into the upper part of the section. The object of research is deposits of the upper part of the section. Despite the large factual material available in various organizations, the upper part of the section in relation to evaluation of gas content is the least studied and described in the literature zone. This is due to the fact that the main research interval in the Southern Caspian is concentrated in areas with high oil and gas potential. This interval is the productive series and underlying deposits, which are included in the zone of intensive generation of oil and gas. The younger sediments accumulated before the Absheron regiostage, mainly consisting of clay sediments, were of no interest. In many works this zone is described as dissected series of quaternary deposits. Research methods are based on modelling thermodynamic balance of hydrocarbon gases in order to establish the formation zone of gas hydrates. The authors have used the data of temperatures and pressures measured in the wells of the South Caspian, as well as the data from 160 seismic acoustic profiles, interval velocity sections as well as data on oil and gas occurrences within the shelf zone of the South Caspian. As a result of thermodynamic equilibrium studies, the volumes of gas hydrate zones were calculated. Based on calculations, it is established that the total gas volumes for the study area are 1,151013m3 of gas. As a result of interpretation of seismoacoustic data, it is established that the intensity of gas manifestations varies both in area and depth. In the zones adjacent to the deep-water part of the South Caspian, the presence of anomalies characteristic of gas zones increases in comparison with the instrument zones. Based on the analysis of the data on gas manifestations, it can be concluded that the upper part of the section of the South Caspian is strongly enriched with gas, and the intensity of gas manifestations in the lower part is the highest. Oil shows within Khali, Chilov adasi, Palchig Pilpil, Chirag structures indicate that these structures are more favorable for the search for oil deposits. The reservoir water is fixed in a wide range of depths. The obtained results enable to predict the receipt of significant volumes of fluids in the upper part of the section of the deep-water part of the South Caspian. Актуальность. Геологическое строение и батиметрия морского дна глубоководной части Каспийского моря указывают на возможность образования значительных объемов газогидратов. Анализ опубликованных и неопубликованных материалов по газогидратам Каспийского моря показал, что в основном все работы базируются лишь на изучении скопления газогидратов Элм, Боздаг, площади Абшерон, а также термодинамических факторах региона (без учета реальных значений температуры и давления) с целью определения возможной зоны их скопления. Цель исследования заключается в подсчете объема углеводородных газов газогидратов по термодинамическим данным, а также в изучении и прогнозировании их поступления в верхнюю часть разреза. Объектом исследования являются отложения верхней части разреза. Несмотря на большой фактический материал, имеющийся в различных организациях, верхняя часть разреза в связи с оценкой газоносности является наименее изученной и описанной в литературе зоной. Это связано с тем, что основной интервал исследований в Южном Каспии сосредоточен в участках с высоким потенциалом нефти и газа. Этим интервалом является продуктивная толща и подстилающие отложения, вошедшие в зону интенсивной генерации нефти и газа. Более молодые отложения, накопившиеся до абшеронского региояруса, в подавляющем случае состоящие из глинистых осадков, не представляли интереса. Во многих работах эта зона описывается как нерасчлененная толща четвертичных отложений. Методы исследования основаны на моделировании термодинамического равновесия углеводородных газов с целью установления зоны...Keywords
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