Balancing Depositional Concepts and Seismic Attributes in Reservoir Models of Fluvial Deposits at Wheatstone, NW-Shelf Australia

Katz, Bodo¹; Sibley, David M.²; Vonk, Adam J.²
¹Energy Technology Company, Chevron, Perth, WA, Australia.
²Austalasia Business Unit, Chevron, Perth, WA, Australia.

A significant knowledge base for the presence and distribution of fluvial deposits exists in the Mungaroo Formation of the Wheatstone area of Western Australia. Good quality in-field seismic information allows for some predictions of the distribution of fluvial deposits; areas of high quality seismic imaging in the region provide additional stratigraphic understanding to the field. In addition, a large base of both in-field and near field well and core information provides insights and constraints for the depositional architecture of the field.

We show in three examples how reservoir models can combine the various pieces of information into a coherent subsurface picture that allows for reducing uncertainty in volumetric and connectivity estimation, as well as delivering a robust development plan. First, we show how to bracket reservoir uncertainty ranges through integration of information from analogues, depositional model ranges, seismic channel shapes, and in-field and near-field wells through probabilistic modeling of the above parameters in a regional model. We then show how to balance local and regional well and seismic data sources in the field characterization through the use of Multi-Point Statistics (MPS) and through nested modeling techniques. And last, we demonstrate the impact of how one change in understanding of the depositional setting in one part of the reservoir has resulted in a volume shift, in EUR distribution, as well as development well placement.

The examples intend to demonstrate the value gained from thorough, integrated stratigraphic work through reservoir modeling for a multi-billion dollar, multi-Tcf gas field development.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012