FLOW UNITS IDENTIFICATION AND CHARACTERIZATION OF HYDROCARBON BEARING ZONES, AQUA FIELD. NIGER-DELTA, NIGERIA
ABSTRACT
Reservoir characterization is the key to a successful oil field development program. The recovery efficiency of any reservoir is influenced by its heterogeneities; particularly the distribution of porosity and permeability. To develop a reservoir model that represents the reservoir properties we must be able to define the vertical distribution of reservoir properties “flow units” and each flow unit has its own characteristics which control fluid flow behaviour. The understanding of flow units allows us to identify preferential flow zones. This study involves the determination of the number and distribution of hydraulic units (flow units), key flow unit characteristics and qualitative interpretation of flow performance using Stratigraphic Modified Lorenz Plot (SMLP) and Flow Unit Speed (FUS) parameter in the three selected wells of “Aqua Field”, Niger-Delta, Nigeria. A total of forty-two (42) flow units were identified throughout the hydrocarbon bearing intervals of Wells B, D and E. Well B has sixteen (16) flow units with six (6) speed zones and ten (10) baffles zones. Well D has five (5) flow units delineated, with three (3) speed zones. Also a total of twenty-one (21) flow units were delineated for Well E with nine (9) flow unit speed zones; the rest being baffles. The number of flow units delineated is an indication of the exgtent of the reservoir heterogeneity. The dominance of the speed zones to the baffles zones in a hydrocarbon bearing interval is an important factor in the flow performance and recovery efficiency during enhanced oil recovery. These various hydrocarbon bearing intervals of “Aqua Field” are dominated by baffles and an anticipated long term production will be sustained by the baffles zones. This will be characterized by a steady to slow decline production behaviour. This study has shown that Stratigraphic Modified Lorenz Plot (SMLP) is a cost effective, quick look method of characterizing petrophysical flow units.