Fluvial and aeolian interactions in modern and ancient dryland continental sedimentary systems: implications for reservoir heterogeneity

Quantitative stratigraphic prediction of the three-dimensional form of sedimentary architectures and associated heterogeneities arising from fluvial and aeolian interactions and preserved as accumulated stratigraphic successions is notoriously difficult, meaning that prediction of 3D stratigraphic architectures in subsurface fluvial and aeolian reservoirs is challenging. This study comprises four discrete but related research components: (1)analysis of aeolian dune-field geomorphology through a remotely sensed analysis of four parts of the Al Rub’ Al-Khali Desert, Saudi Arabia; (2) analysis of types of aeolian-fluvial system interaction in modern dune-field margins through study of the morphological expression and areal distribution of 130 examples of fluvial-aeolian interaction mapped by high-resolution satellite imagery from 60 deserts around the world; (3) analysis of the preserved stratigraphic expression of an ancient mixed aeolian and fluvial succession via analysis of the upper part of the Wilmslow Sandstone and the lower part of the overlying Helsby Sandstone formations, Sherwood Sandstone Group, UK; (4) development of a series of predictive, semiquantitative facies models with which to account for the geological complexity and origin of mixed aeolian-fluvial successions. Principal finding are as follows: (1) observations from the Rub’ Al-Khali Desert have enabled the spatial rate of change of morphology of aeolian subenvironments to be characterized and described through a series of empirical relationships; (2) aeolian-fluvial interaction case-study examples have been classified to propose a framework of ten distinct types of system interactions;(3) outcrop analysis of an ancient preserved succession reveals mechanisms for the accumulation and preservation of aeolian and fluvial successions, and demonstrates the role of water table on the development and preservation of a water-table influenced aeolian system; (4) results from this study have enabled the development of facies models that serve as the basis for gaining an improved understanding of controls governing the detailed sedimentary architecture of preserved aeolian-fluvial successions