Building a Realistic Geological and Reservoir Model for a Stratigraphic Unit Displaying Varying Depositional Environments: Greater Burgan Field, Kuwait

Abstract

To better understand optimal hydrocarbon depletion of the giant Burgan Field in Kuwait, an integrated study on small-scale heterogeneities through reservoir modelling was performed of the Lower Cretaceous Upper Burgan unit of the Burgan Formation. This included modelling of geologic facies, pore space, fluid saturation and permeability. The result was a “fit for purpose” static model for use in either streamline or conventional dynamic simulation and the determination of well drainage areas, new well placement and production forecasting. The Upper Burgan consists of three sub-units that are, in ascending stratigraphic order, the BU3, BU2 and BU1. An area of moderate connectivity within the BU3 was selected for this detailed reservoir study. Static model construction utilized a hierarchical workflow and included more than 100 wells with a full suite of petrophysical logs. The BU3 consists of a number of depositional facies; including tidal flat, tidal channel, tidal bar, shoreface, offshore, and bay. A conceptual depositional (depofacies) model was developed through the integration of regional geology, sedimentology, core and log motifs. Three-dimensional (3D) depofacies probability cubes were generated by integrating the depofacies from well interpretations with the conceptual depositional model. These probability volumes constrained the facies model and ensure that well data and the depositional characteristics were honored. The defined object modeling (DOBM) method provided flexibility in modeling the mixture of facies observed in the 3SU, which acted as a constraint to the petrophysical property models and resulted in a realistic representation of the subsurface pore space, fluid saturation and permeability.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015