Abstract
The Burgan-Wara formations from Southeast Kuwait (Greater Burgan field) constitute the largest known siliciclastic oil reservoir on earth. A specific workflow combining geological, geophysical and reservoir engineering techniques was developed to build a fully integrated and representative geomodel of the field.
The sedimentology and stratigraphy were here reviewed in terms of depositional environment and lateral stratigraphic correlation. The variability inherent to the depositional style leads to a complex reservoir scheme. Lower Burgan is dominated by stacked braided channels representing homogeneous, high quality reservoirs. Higher in the stratigraphy, lateral facies variability and heterogeneities are observed in tidal dominated units. Mud dominated units occur within the Upper Burgan and Lower Wara formations and provide good sealing capacities. Small, laterally strongly variable and heterogeneous fluvio-tidal dominated units are representative of the Upper Wara Formation.
A 3D geological model of more than 900 million cells was built, based on the new structural and stratigraphic framework interpretations to capture the complexity of the Burgan Field reservoirs. Rock-types were defined, based on more than 900 well logs and core petrophysical properties measurements. The seismic reservoir characterization, focused on inversion techniques and calibrated with the newly defined rock-types provided crucial information on sandstone proportions distribution, especially in areas with lower well control.
The first attempt to simulate, at high resolution, the largest siliciclastic oil field in the world provides a comprehensive way to understand the field heterogeneities and behavior. The updated geological model, based on new interpretations allowed characterizing the major reservoir heterogeneities and has significant impact on the reservoir management of this giant field.
