Abstract
Exploiting the full potential of a complex reservoir in Libya's largest oil field is inherently challenging due to variable reservoir characteristics such as thickness, heterogeneity, water height uncertainty, and sub-seismic faulting. These geological complexities can significantly hinder effective navigation and optimal placement within hydrocarbon-bearing zones, necessitating the utilization of advanced reservoir navigation tools. This paper highlights how advanced geosteering technology can overcome complex reservoir challenges, leading to better well placement and increased hydrocarbon production.
To achieve the well objective, it is critical to optimally land the well in the target zone, mitigating the challenges due to geological uncertainty. Drilling further in the lateral section requires maintaining the trajectory in the best reservoir properties while tracking the Oil Water Contact (OWC) below for any elevation changes. A feasibility study based on offset data respecting the area's geological setting was undertaken to determine the best fit-for-purpose technology. Extra Deep Azimuthal Resistivity (EDAR) technology was identified as the optimal solution to detect resistivity contrasts remote from the wellbore, thus avoiding penetration.
EDAR ultra-high-definition (UHD) real-time inversion analysis facilitated the precise mapping of multiple resistivity layers and accurate delineation of the Oil Water Contact. This ensured well-informed and proactive geosteering decisions to land the well and expose the reservoir optimally. The EDAR inversion continuously mapped the top of the target zone along with the local dip variations, interpreted sub-seismic faults, and defined their throw. This technology was essential for maintaining a precise and smooth trajectory in a geologically complex area, achieving 100% reservoir contact, and optimizing hydrocarbon recovery. The information acquired from the inversion summary, such as resistivity distribution and structural changes, is valuable input for enhancing the field development plan of the area.
The use of advanced geosteering tools improves navigation accuracy in complex reservoirs, setting a new benchmark for challenging environments.