Successful Implementation of Advanced Inversion in a New Field Achieved 100% Reservoir Exposure in a Complex Heterogeneous Reservoir – An Integrated Solution Comprising Near and Far Field LWD Measurements

Abstract In a new field in the UAE offshore, the field development plan was initiated by drilling the first lateral oil producer in a low-resistivity reservoir characterized by structural uncertainty, reservoir heterogeneity, and the presence of high-permeability streaks that can act as conduits for water, potentially compromising the well's productivity. To achieve the navigation objective, two target reservoir subzones, separated by an impermeable dense zone, each with independently associated water risks, need to be exposed. To maximize reservoir exposure, maintain a safe distance from denser layers, and stay close to the top of the second target zone to avoid the permeable lower part, any changes in the water level must be mapped accurately. A feasibility study assessed the mapping results of an Extra Deep Azimuthal Resistivity (EDAR) inversion in this environment. This hybrid inversion method uses adaptive parameter scanning and efficiently computes numerous intermediate models to enable accurate high-definition multiple boundary mapping. As a result of this study, the EDAR tool was identified as an optimal solution and integrated into a triple combo BHA. The advanced inversion from the EDAR tool enhanced the understanding of the geological setting around the well area. EDAR inversions consistently mapped the reservoir boundaries, and integration with near-wellbore measurements aided in optimizing well placement for the most favorable reservoir properties. The confident mapping of the second target top ensured that the trajectory stayed close to it, thus avoiding exposure to the permeable zone in the lower part. The EDAR inversion was used to update the structural changes along the wellbore in real-time. The information gathered from EDAR advanced inversion established that no elevated water zone was observed within the thickness of the target reservoir subzones. 3D visualization of acquired information from EDAR inversion, such as distribution of resistivity and structural variations, gives a better insight into the reservoir architecture. Integrating petrophysical analysis with EDAR inversion summary will help optimize the completion design and can be considered an immediate after-the-drilling service application. Integrating the inversion information into the 3D model reduces uncertainty and aids field development planning.