oa Importance of Trace Fossils and Bioturbation in Carbonate Reservoir Characterization and Reservoir Quality: Examples from the Khuff Formation

Several aspects of the study of trace fossils (ichnology) are relevant for the characterization of carbonate reservoirs, of which the following are most important: (1) facies interpretation by utilizing the ecological information of trace fossils and ichnocoenoses; (2) reservoir zonation by identifying sequence boundaries and flooding surfaces for correlation; and (3) reservoir quality and connectivity, which is directly affected by bioturbation. The vast shallow-marine carbonate platform of the Middle Permian to Lower Triassic Khuff Formation in the Middle East comprises broad facies belts with little significant changes in the lithofacies. However, trace fossil assemblages and ichnofabrics, in combination with sedimentological observations, serve in subdividing this platform and in distinguishing sub-environments. From proximal to distal, these are sabkha and salina, tidal flat, restricted lagoon, open lagoon, platform margin, shoreface/inner ramp, slope/outer ramp and basin/deeper intra-shelf. In this way, changes in relative sea level can be better reconstructed and guide the sequence stratigraphic interpretation.