The Aptian Dariyan (Shu'aiba) Formation is one of the major Cretaceous reservoirs in the Middle East. Despite its economic significance, an understanding of the influence of depositional facies and a sequence of diagenetic events on its reservoir quality remains limited. Here, we address this challenge through analysis (facies, petrophysics, geochemistry) of a continuous, ∼180 m thick core from NW Persian Gulf, and a fully-automated identification of hydraulic flow units (HFUs). Ten carbonate and four predominantly siliciclastic facies were identified as part of four facies associations, from shallowest to deepest: mixed tidal flats, inner ramp (lagoon and shoals), shallow open-marine mid ramp, and deep open-marine (outer ramp and intrashelf basin). The stacking pattern of facies yields five third-order transgressive-regressive sequences. Three hydraulic flow units (HFUs) were identified and evaluated against lithology and petrophysical values: baffle unit (HFU1), normal unit (HFU2), and permeable unit (HFU3). The permeable unit exhibits good storage capacity and moderate flow capacity. The data reveal an overall complex paragenetic and porosity-modification history of the Dariyan Formation. The overwhelmingly mud-dominated texture of the facies, along with meteoric-zone dissolution under a predominantly warm and humid greenhouse climate during periods of relatively low sea level, and subsequent fracturing during deep burial played a major role in controlling the reservoir quality.