Revolutionizing Horizontal Offshore Well Operations: Maximizing Reservoir Exposure Through the Implementation of High-Definition Reservoir Mapping While Drilling

Abstract The use of High-Definition Reservoir Mapping While Drilling (HD-RMWD) has been increasing worldwide as a technology that can provide reservoir mapping while drilling with deeper depths of detection in order to give better understanding on the reservoir characterization. The technology was able to provide valuable information on the boundary position, thickness, and structure of the reservoir. With a depth of detection of up to 30 meters, the technology was successfully used to maintain trajectory inside the Pliocene globigerina limestones reservoir in East Java Basin and maximize target length to increase production output. Along with the latest combination of improved antenna designs and significant software enhancements, HD-RMWD electromagnetic propagation resistivity method provide deeper depth of detection with better vertical resolution to depict the reservoir boundary and evaluate quality of reservoir based on resistivity profile. Given the complexity of the geological condition, technology that can map the entire reservoir structure is required. The HD-RMWD was used to locate the trajectory inside the target reservoir in this clastic carbonate environment that holds some high degree of geological uncertainties. Comprehensive pre-job modelling assessment and evaluation were conducted to examine the necessary adjustment in the event of structure and reservoir quality uncertainties. In real-time execution, it was observed while drilling that the target reservoir which was initially thought to be continuous based on seismic data and offset wells, appeared to be discontinued. The discontinuity was then revisited and re-interpreted as a fault that was not identified in pre-drill seismic interpretation. The real-time inversion result from HD-RMWD technology was able to give critical information during drilling allowing the team to make proper adjustments based on thorough analysis from integration of measurement on inversion, formation evaluation logs, cutting descriptions, and mud logs to optimize reservoir exposure. The outcome of this technology resulted in significantly better reservoir properties compared to prognosis due to optimum well placement, and additionally the well test resulted in higher well deliverability of over 30% than initial plan. This paper will discuss the implementation of HD-RMWD drilling application in conjunction with formation evaluation logs as a game changer in horizontal well operation in this area.