Detailed mapping, three-dimensional modelling and upscaling of a mixed-influence delta system, Mitchell River delta, Gulf of Carpentaria, Australia

Abstract Data from satellite imagery, field measurements and analogues were used to construct a three-dimensional (3D) geocellular facies model of the Mitchell River Delta, Australia; a modern mixed-influence delta system. Detailed mapping identified 16 different facies elements and classified the delta as tide dominated, fluvially influenced and wave affected. The 3D model was subjected to varying degrees of upscaling of the horizontal and vertical dimensions and allowed comparison of volume and connectivity changes throughout. The upscaling process, to coarser grid cells up to 100 m horizontally and 4 m vertically, created false compartmentalization of facies bodies and significant changes in facies bulk volumes. The vertically upscaled models produced greater changes when compared to the horizontally upscaled models. Key changes in reservoir facies connectivity and bulk volume due to upscaling are associated with the facies architecture, including the elongate and thin morphology of beach ridge and channel facies in this mixed-influence delta system. Recognition of the defining reservoir features and incorporation into reservoir modelling methodology can improve volumetric estimation and allow for better predictions of reservoir connectivity in ancient delta systems.

[1]  B. Jones,et al.  Riverine—tidal interactions in the monsoonal Gilbert River fandelta, northern Australia , 1993 .

[2]  B. Thom,et al.  Coastal morphodynamics in North Australia: review and prospect , 1986 .

[3]  D. Larue,et al.  Flow units, connectivity, and reservoir characterization in a wave-dominated deltaic reservoir: Meren reservoir, Nigeria , 2004 .

[4]  R. Ainsworth Prediction of stratigraphic compartmentalization in marginal marine reservoirs , 2010 .

[5]  E. G. Rhodes,et al.  Depositional model for a chenier plain, Gulf of Carpentaria, Australia , 1982 .

[6]  R. Nanson,et al.  Dynamic spatial and temporal prediction of changes in depositional processes on clastic shorelines: Toward improved subsurface uncertainty reduction and management , 2011 .

[7]  K. Webber,et al.  Framework for constructing clastic reservoir simulation models , 1990 .

[8]  R. Ainsworth Sequence stratigraphic-based analysis of reservoir connectivity: influence of depositional architecture – a case study from a marginal marine depositional setting , 2005, Petroleum Geoscience.

[9]  William E. Galloway,et al.  Process Framework for Describing the Morphologic and Stratigraphic Evolution of Deltaic Depositional Systems , 1975 .

[10]  J. M. Coleman,et al.  Modern River Deltas: Variability of Processes and Sand Bodies , 1975 .

[11]  A. Chivas,et al.  The sedimentary record of palaeoenvironments and sea-level change in the Gulf of Carpentaria, Australia, through the last glacial cycle , 2008 .

[12]  L. Stright Modeling, Upscaling, and History Matching Thin, Irregularly-Shaped Flow Barriers: A Comprehensive Approach for Predicting Reservoir Connectivity , 2006 .

[13]  D. Larue,et al.  WHY IS RESERVOIR ARCHITECTURE AN INSIGNIFICANT UNCERTAINTY IN MANY APPRAISAL AND DEVELOPMENT STUDIES OF CLASTIC CHANNELIZED RESERVOIRS? , 2008 .

[14]  Boyan K. Vakarelov,et al.  Geometric attributes of reservoir elements in a modern, low accomodation, tide-dominated delta , 2012 .