Analogue Geometry Data and the Value of Complex Attribution: A Case Study of the Large Scale Controls on Fluvial and Deltaic Channel Geometry
Compilations of reservoir geometry analogue data have long been used to infer shape and volume parameters for subsurface reservoirs, especially where direct imaging is difficult or where the required resolution for a particular problem is beyond the capability of current imaging methods. Most commonly a single or preferred analogue is chosen or, alternatively, data are selected from a very wide range of examples. The former suffers from the inevitable fact that every analogue contains case-specific variation whereas the latter typically results in unacceptably large data spread. The addition of detailed attribution to analogue data provides the potential to address these issues by building composite analogue datasets, allowing investigation of both large scale controls and relationships and investigation of the degree of case-specific variability. An example of the methodology will be presented, additionally illustrating some of the key controls on fluvial channel geometry.
The relationship between channel body width and thickness is explored and linked to planform geometry in terms of common descriptors of sinuosity and channel planform classification. These analogue data were subsequently attributed with additional descriptors derived from a variety of global GIS coverages, to include tectonic setting, climate/palaeoclimate and other potential controls on geometry. In this case study, a large volume of richly attributed channel geometry are used to illustrate the relationship between modern and ancient data in different climatic and tectonic settings. The relationship between channel width and thickness under different climatic regimes varies significantly. The relationship between channel wavelength, amplitude and absolute sinuosity taken from modern satellite imagery also varies dramatically with climate regime. Examples of direct application of the results in an exploration context will be illustrated.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California