A Statistical Approach To Discern Lithological Heterogeneity And Connectivity Of Tidal Deposits In The Subsurface Based On Data From Modern And Ancient Analogs: Examples From The Middle Jurassic Dhruma Formation, Saudi Arabia’’.

Sand bars are notable depositional elements in many tide-dominated or -influenced environments such as estuaries, deltas and shelves. The sand bars that accumulate in estuaries, which are the focus of this study, typically accumulate in the middle and outer parts of tidal estuaries, and the inner parts of mixed energy estuaries. Estuaries have a long-term sediment preservation potential due to their sheltering morphology ( Biggs and Howell, 1984 ; Demarest and Kraft), which makes preservation of estuarine deposits, including tidal sand bars, extremely likely. Moreover, being systems that are developed in transgressive settings, estuaries with tidal sand bars have significant potential for burial by subsequent highstand, mud-prone deposits such as shelf mudstone or prodelta mudstone (e.g. Shanmugam et al., 2000 ; Chen et al., 2014 ). Therefore, tidal sand bars are encouraging reservoir bodies to target in the subsurface. However, their heterogeneity and connectivity in the subsurface is not well understood. To bridge the gap in knowledge and improve the understanding of the tidal sand bar morphology and their internal anatomy, a quantitative study was conducted. Specific objectives of the study are as follows: I) investigate the geometry and size of tidal bars known from modern systems and ancient successions; ii) illustrate their sedimentological characters, iii) investigate the nature of juxtaposition of tidal sand bars in association with other estuarine and shallow-marine elements; iv) highlight tidal-bar development and preservation; and vi) present implications of the results for reservoir prediction and characterization.