Carbonates heterogeneity is a continuous challenge for subsurface experts. The case in hand illustrates the advantage of data integration between Logging While Drilling (LWD) including Nuclear Magnetic Resonance (NMR), High-resolution image and Wireline (WL) formation testing and fluid sampling. The formation evaluation integration analysis results are used for characterizing the rock quality across multiple reservoir zones and to determine the optimum zones to be drilled horizontally and completed using the inflow control device (ICD) completion.

Appraisal and improvement of the lateral drainage area of the reservoir are the main objective of the field development strategy, by drilling pilot holes to evaluate Cretaceous carbonate layers then targeting the optimum zone for lateral side-track based on the provided data. Therefore, the plan has initiated by deploying the advanced LWD including the Gamma Ray, propagation Resistivity, Neutron, Density and Micro-Resistivity imaging along with NMR to acquire all the needed data for formation evaluation and reservoir characterization. The formation pressure testing and sampling device has been deployed using Wireline (WL) for the comprehensive evaluation of subsurface resources.

In this study, the reservoir petrophysical properties including total, effective porosity, permeability, movable fluid and bound water volume provided from NMR played an important role for the reservoir characterization and enhancement of the final formation evaluation results, based on the NMR results the formation testing / sampling points were decided. The Micro-Resistivity image revealed various types of geological features such as the conductive, enhanced, resistive fractures and different bedding plane in addition to different geological textures were interpreted along the well trajectory and was used to fine tune the formation testing and fluid sampling zones. The fluid mobility analysis from formation testing is used to calibrate the NMR permeability index along with the comparison with core data, also, the fluid characterization and sampling result are integrated with the rest of the data to formulate better reservoir understanding. The final integrated results from all the data and analysis used to identify the highest potential zones, therefore the side-track lateral drain was planned and geosteered based on the data integration results from the pilot hole. By extending the pilot hole understanding to the lateral section, the lateral section completed successfully across the optimum zones.

This paper provides insight into the integration of the Open Hole logging data from Logging While Drilling and Wireline to eliminate the uncertainty of the reservoir characterization and Formation Evaluation analysis to sustain and increase the oil production.

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