New data on depositional environment of Jurua Formation terminal sediments, Solimoes Basin, Brazil

Abstract

It has been for the first time established on the core taken from two wells that JR10 reservoir sediments (Upper Jurua, Formation Carboniferous) were deposited in the conditions of deltaic and alluvial coast with semiarid climate and in marine-terrigenous settings. JR10 reservoir differs in its lithological composition and structural architecture from the underlying layers of the Jurua formation and the overlying Carauari formation by the absence of carbonate and sulphate rocks and significant content of carbonaceous terrestrial plant fossils. The change of thickness from the south-east to north-west direction is associated with progradational nature of the deltaic coast evolving to the same direction.