Typical Depositional Sequence of Middle Jurua Subformation in the Solimoes Basin, Brazil

Based on facies analysis of cores from five wells and sequence-stratigraphic modeling, 12 III-order sequences were separated in the Middle Jurua subformation, which have been combined into three II-order sequences (JR70, JR60, and JR50) and were traced laterally. The complete section of III-order sequence in Middle Jurua sediments includes (upward) alluvial and eolian sandstones (LST), normal marine limestones and secondary dolomites (TST), and lagoon, intertidal, and sebkha evaporites (HST). Facies maps of second-order sequences were built which will serve as the basis for planning new wells and predicting reservoir intervals. It has been established that the sandstones of eolian complexes in the eastern and central parts of the work area are characterized by the best reservoir properties.