Relative sea-level changes and sedimentary facies development of the lowermost Cretaceous (Berriasian–Valanginian) cycles in the north of Ar Riyad city, Saudi Arabia

Evaluation of the hydrocarbon source rock and the reservoir characterization of the Minagish Formation using wireline logs

“…There is a sharp contact which appears on the GR-log between the peloidal wackestone to packstone of the Upper Minagish Member, which is characterized by a Transgressive Systems Tract (TST), and the medium- to coarse-oolitic grainstone of the Middle Minagish member, which is characterized by a Highstand Systems Tract (HST) ( Nath et al., 2014 ; Datta et al., 2013 ) ( Figure 8 ). The Middle Oolitic grainstone is the producing reservoir deposited in a single third-order sea-level cycle and is composed of stacked broadly coarsening parasequences upward due to a high prograding ramp setting ( Nagm et al., 2018 ; Wolpert et al., 2015 ) ( Figure 8 ). There is strong evidence from the GR-log about the changing of the reservoir facies into more argillaceous limestone toward the north of the study area, indicated by the shape and magnitude of the recorded GR ( Figure 9 ).…”