Integration of Extra Deep Azimuthal Resisitivity Application with Formation Evaluation Technologies Reduces Uncertainties and Enchances Reservoir Navigation in the First Extended Reach Well in a Carbonate Reservoir of a Mature Field – A Case History from Abu Dhabi Onshore

Abstract

A multi-disciplinary integrated approach to well construction and navigation is demonstrated in an extended reach well drilled in a mature waterflooded limestone oil reservoir with water override and slumping issues. Integration is vital to optimizing drilling operations, increasing efficiency and enhancing reservoir navigation to maximize production and recovery from a well. The wells primary objective was to maximize reservoir exposure with an extended reach profile while mapping injection water override / slumping intervals and geological structure while avoiding any potential nonproductive zones. Data acquisition pertaining to reservoir characterization, fracture and fault identification were planned to enhance reservoir understanding and to optimize completion design. While drilling a long horizontal section can increase sustainability and recovery potential, the risk of high cost and reduced well life can become a reality if not planned and executed properly. Based on the existing field knowledge and petrophysical data from offset wells, a reservoir navigation strategy was developed respecting the structural and geological setting of the area. A feasibility modeling study incorporating injection water override / water slumping scenarios predicted the Extra Deep Azimuthal Resistivity (EDAR) LWD tool capable of mapping water slump intervals with high confidence at a remote distance from the wellbore which would be key to optimal reservoir navigation. A BHA consisting of RSS, Near Bit Gamma, Density & Porosity, High Resolution Resistivity Image along with Extra Deep Directional Resistivity service was deployed for the first half of the Extended Reach lateral section. The second half of the lateral section was drilled by replacing the Density & Porosity tool containing radioactive sources with a NMR porosity tool to decrease the risk of a lost in hole source. The 8500 ft lateral section was successfully navigated validating proof of concept to include such extended reach wells in future well development plans. Extra Deep Directional Resistivity inversion mapped the reservoir architecture reducing saturation, structural and geological uncertainties and water slumping. Reducing the uncertainties, supported informed geosteering decisions to achieve 100% reservoir exposure while maintaining minimum wellbore tortuosity. This smooth well profile facilitated in running the longest limited entry liner completion in the field. Integrating the inversion result with fracture evaluation from High Resolution Electrical Image, NMR porosity and permeability distribution enabled optimization of the completion design. Updated surfaces from the inversion result were integrated into the customer 3D model for future field development. This integrated approach enhanced Reservoir Navigation enabling a better understanding of the petrophysical and geological settings of the reservoir in real-time which can maximize the production potential and ultimately, recovery from the field.