Department of Petroleum
Engineering, Heriot-Watt University
Abstract: Critical Heterogeneities in Aeolian Systems and Their Effect on Flow Performance in Reservoirs.
Summary
Heterogeneity in aeolian systems exists at a number of scales and will affect fluid movement through the reservoir to greater or lesser extents. Detailed descriptions of these heterogeneities are common in the literature (i.e. Chandler et al. 1989). Recently, characteristics of these heterogeneities have been incorporated into reservoir models and their associated up-scaled flow simulations in an attempt to predict reservoir performance (Sweet et al. 1997).
The distribution of these heterogeneities is a function of the system architecture which results from the type of aeolian system (or part of the system) that the reservoir sequence was deposited in. Therefore, the key to accurate reservoir prediction lies in the correct interpretation of the subsurface system, so that the appropriate architecture is honoured in the reservoir modelling and simulation.
Two end member 3D reservoir models were constructed, using
analogous outcrop sequences (Cutler Formation and Slickrock Mbr. of
the Entrada Formation) to determine size distributions and
architecture of fluvial influenced and marine influenced aeolian
systems respectively. These models were upscaled and subjected to
depletion/aquifer incursion simulations to replicate similar
conditions to those experienced during initial production from
Southern North Sea gas reservoirs. The results indicate that
significant differences in water breakthrough and flood
front
morphology are experienced as a function of the architecture, thus
illustrating the importance of accurate architectural determination
prior to simulation if realistic prediction is to be achieved
AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas