ROLE OF NEOTECTONICS IN GENERATING THE GAS-CONDENSATE POOLS OF WESTERN SIBERIA

Abstract

A general tectonic uplift ranging from 50 to 400 m is characteristic of the Recent development of the West Siberian plate, and could not fail to affect the development of oil and gas fields there. The authors have derived new information from a comparison of data on the composition of hydrocarbon fluids with data on the neotectonics of this province. To derive these data, they analyzed the vertical changes in the composition of hydrocarbon gases and gas condensate in the multilevel Urengoy, Bovanenkovo and Kharasavey fields in northwestern Siberia. A relationship is observed between neotectonic processes, which intensify the vertical migration of hydrocarbons, and the systematic change in composition in gaseous and liquid hydrocarbons in multilevel fields. Therefore, the individual gas and condensate pools in multilevel field are geochemically related to each other. The emplacement and change in the composition of the gas and condensate pools in the section is to a great extent controlled by retrograde processes, which promote systematic differentiation of gaseous and liquid hydrocarbons during their subvertical migration. But neotectonic movements was undoubtedly a controlling factor in that vertical migration.