Maximizing Reservoir Contact While Minimizing Impact of Water Encroachment in Deviated Wells Using Ultradeep Resistivity Reservoir Mapping Tools- A Case Study from an Offshore Field in Abu Dhabi

Abstract Marginal field development presents numerous challenges throughout the entire lifecycle of the field from exploration-to-production. These fields are often characterized by inherent limitations, including complex reservoir properties, limited data availability, and significant economic constraints. As a result, innovative strategies are required to overcome these challenges and achieve efficient oil recovery while minimizing costs and operational risks. Common field development strategies aim to maximize oil recovery, reduce operational costs, and adhere to stringent safety guidelines. One critical concern in marginal fields is water encroachment, which can significantly reduce production rates, increase operating costs, and lower overall recovery factors, thus negatively impacting the economic viability of these fields, making their development a complex and costly endeavor. A key strategy to mitigate water encroachment is the optimal placement of production wells above the oil-water contact (OWC) to maximize oil recovery and minimize water production. However, limited well data prior to field development creates uncertainty in estimating accurate level of OWC. While OWC is commonly identified through open-hole log interpretation and production test data, discrepancies between these methods persist. Traditionally, a pilot hole has been the standard practice to confirm the OWC and minimize bypassed oil, but this practice is costly and time-consuming, adding additional financial and operational burdens to the development of marginal fields. To address this, the Ultra-Deep Resistivity (UDR) logging tool has been proposed as an alternative, potentially eliminating the need for additional pilot hole drilling. The UDR tool offers an advanced solution for this issue especially during the drilling of highly deviated production wells. The UDR tool provides resistivity measurements at multiple depths of investigation, enabling early detection of water zones and real-time mapping of the OWC at the reservoir level. These capabilities allow for interactive well trajectory optimization and precise geosteering to avoid water zone penetration, thus minimizing water production and ensuring dry oil recovery with zero water cut, making UDR a transformative solution for optimizing marginal field development in complex environments. The UDR Geosteering of highly deviated oil production wells successfully maximized oil recovery in the field. This process also contributed to improved sweep efficiency and optimized the planning of future wells in the area.