New fluid dynamic model for formation of giant hydrocarbon deposits

Abstract

Geomechanical models of fluid dynamics with both one-phase and two-phase fluids in overthrusts and faults, more than 7km deep, are proposed in this work. Based on the models, we studied accumulation conditions and mechanisms of formations of giant gas and gas condensate deposits in structures like the Astrakhan Arch carbonate massif. The Astrakhan carbonate massif is characterized by an increase in reservoir capacity of carbonate rocks owing to generation of joint during faulting. Moreover, the entire Caspian depression serves as a giant oil-generating basin, which is able to supply any trap with hydrocarbons within this region. Shifts of fault boundaries cause self-oscillation processes in these faults. The oscillations squeeze fluids out from faults intooverthrusted rocks from where they migrate along weakness zones. Migration of a two-phase fluid in the porous medium takes place between two reverse self-oscillations. That results in gas accumulations in fractured cavities (pockets. Any fluid migration is initially induced by lateral stresses in the crust and lithosphere, which in turn result from globalgeodynamic processes related to the mantle convection. The global processes are further transformed into regional movements along weakness zones.