An Innovative and Integrated Reservoir Characterization Driven by Modified Saturation Height Model and Variable Fluid Contacts for Challenging Complex Sandstone Reservoir

Abstract

Abstract It has been known that the uncertainty of original oil in place (OOIP) is one of main challenges in proper reservoir development. The field has complex reservoir subunits, variable fluid contacts and structural and stratigraphic sand discontinuities. Therefore, reliable reservoir characterization and estimation of fluids in place requires an integrated approach of all available data of petrophysical evaluation, special core analysis (SCAL), geology, geophysics, reservoir rock typing (RRT), saturation height model (SHM) and fluid analysis. An innovative and integrated petrophysical evaluation have been studied and used in reservoir characterization. An advanced permeability log has been developed from porosity, clay bound, pore size, core and mobility data. It has used the modification of SHM that based on SCAL data including MICP, Centrifuge, Porous Plate and Relative Permeability data for every RRT and variable fluid contacts for subunits. An initial water saturation, and residual oil saturation from SCAL data have been used in evaluation. The pulse neutron capture and PLT have been used to verify fluid contacts and water saturation changes in complex sandstone reservoirs during production. The advanced integrated evaluation approach of subsurface and well test data has been used to provide reliable and good of reservoir properties and results on porosity, permeability, fluid contacts, reservoir rock typing and initial water saturation initial oil in place. For every reservoir subunits, the free water level (FWL) derived from formation pressure has been used to identify an initial oil water contact, and thus it has provided good comparison of Log-Sw and SHF derived Sw for reservoir modeling. The study has provided reliable reservoir characterization, reservoir modeling and for the development for multi-layer and complex sandstone reservoirs. Therefore the innovative integrated reservoir evaluation approach has provided reliable assurance and important benefits for reservoir characterization, optimization and reservoir management. The integrated approach presented in this paper presents an advanced step in the characterization of very flower shaped faulted complex reservoir. It has been utilized for the derivation of advanced permeability log as function of porosity, clay bound, pore size and mobility data per different rock types. Integration of available petrophysical, pressure, and SCAL data to derive the variable reservoir fluid contacts, and develop SHFs for fluids in place estimation and reservoir modeling purposes.