Analysis of all available geological, geophysical, and field data on some gas condensate fields discovered within the Khapchagai megaswell (Vilyui syneclise of the Siberian Platform) as early as the 1960s shows the presence of oil rims in Lower Triassic (horizon T1-III in the Srednevilyuiskoe and Tolonskoe gas condensate fields and horizon T1-Kh in the Mastakhskoe gas condensate field) and Lower Jurassic (horizons J1-I and J1-II in the Mastakhskoe gas condensate field) deposits. The C3 oil reserves in these rims are estimated at several tens of millions of tons of oil. The results are indicative of the oil potential of the Lower Mesozoic deposits not only of the Vilyui syneclise but also of the Lena–Vilyui petroliferous province as a whole, which was always characterized as a gas-bearing province in summary reports.

The results of comparison geological-geochemical study of the Upper Jurassic-Lower Cretaceous sediments of the Preverkhoyansky and Indigiro-Zyryansky basins are considered from the positions of uniform sedimentary basin evolution. Based on lithologic-petrographic data the differences were established in the catagenetic transformations degree of the organic matter (OM) of the Upper Jurassic-Lower Cretaceous deposits from MC3 within the Preverkhoyansky basin and up to MC5 - in the Indigiro-Zyryansky. The distinctions are due, mainly, by a post-collision stage of development of the territory of the Indigiro-Zyryansky basin. The geochemical characteristic of organic matter is given. The identity of composition and distribution of hydrocarbons-biomarkers indicates a common source of the initial OM formed in the conditions of continental facies in the Preverkhoyansky basin. Contrary, OM accumulation of the Upper Jurassic deposits of the western part of the Indigiro-Zyryansky basin occurred in sea and lagoon facies. OM enriched by sapropel material that indicated more oil generation potential of rocks. Based on analysis of the received results the map of prospects of oil-and-gas bearing with allocation of sites for conducting prime exploration works on oil and gas is constructed for the Upper Jurassic-Lower Cretaceous deposits of the Preverkhoyansky and Indigiro-Zyryansky basins.

Рассматривается проблема нефтегазоносности © Электронный научный журнал «Нефтегазовое дело». 2014. №5 http://www.ogbus.ru впадины соленосными являются чарская и метегерская свиты. Сделан вывод, что наличие под среднепалеозойским соленосным комплексом нижнепалеозойского соленосного комплекса может ограничивать потенциал нефтегазоносности межсолевых отложений. Отмечается, что отложения, залегающие над нижнепалеозойским соленосным комплексом на смежных впадинах, имеют весьма скромные нефтематеринские геохимические показатели. На основе изучения геологического строения впадины, сделан вывод о конседиментационном характере развития локальных структур в осевой части впадины верхнепалеозойско-мезозойское время. Предложена принципиальная модель образования локальных структур в осевой части впадины за счет галокинеза солей чарской и метегерской свит кембрия. Предложенная модель глубинного строения Кемпендяйской впадины позволяет увеличить потенциал нефтегазоносности межсолевых отложений за счет миграции углеводородов из-под нижнепалеозойского соленосного комплекса. Приведены обнадеживающие результаты глубокого бурения на территории Кемпендяйской впадины.