oa Prediction of Reservoir and Seal Capacity for Exploring Jurassic Carbonate Stratigraphic Traps, Northern Saudi Arabia

The exploration for stratigraphic traps, especially in carbonates, is challenging and requires carefully<br>detailed analysis of petroleum system elements. Accurately defining the spatial and temporal<br>distribution of source rock, reservoir, and seal facies is essential for exploring stratigraphic traps. This<br>study presents an integrated approach for evaluating reservoir and seal capacity of Jurassic carbonates<br>to explore stratigraphic traps using the Facimage electrofacies prediction and calibrated seismic facies<br>modeling techniques.<br>Core-based rock types were generated for selected Jurassic carbonate reservoir formations by<br>integrating core descriptions, thin-section petrographic data, core plug porosity/permeability, and<br>capillary pressure (MICP) measurements. Reservoir quality and sealing capacity were thoroughly<br>evaluated using core-derived pore-throat size and capillary pressure data from a full spectrum of<br>reservoir and sealing facies. This was followed by calibration of core-derived reservoir and seal facies<br>to well-log responses by constructing Facimage models for selected “Reference Wells” that are<br>extensively cored and analyzed. The Facimage models were rigorously tested by validating predicted<br>electrofacies/capillarity and core-derived rock types, and their sealing capacity. The optimized<br>Facimage model was used to predict electrofacies that represent rock types of varying reservoir quality<br>and seal capacity for all the selected “Application Wells” within the area of interest. The derived<br>electrofacies (rock types) of reservoirs and seals can be upscaled to a seismically detectable level. The<br>upscaled facies were then output as numerical codes into the calibrated seismic facies modeling of 3D<br>seismic volumes using state-of-the-art technologies for analysis, integration, and visualization.<br>The calibrated seismic facies, rock types and porosity models provide lateral and vertical facies<br>changes of reservoirs and seals within 3D volumes. These are critical elements for exploring<br>stratigraphic traps. The Middle and Upper Jurassic reservoirs have been taken as examples for the<br>above approach. Preliminary results have demonstrated that existing stratigraphic trap analogue and<br>potential new stratigraphic traps can be successfully predicted, as shown in the Upper Fadhili and Arab-<br>D reservoirs.