Study on Genesis Mechanism and Development Strategy of Low-Resistance Oil Reservoirs in the Pearl River Mouth Basin: A Case Study of the a Oilfield in the Northern Slope of Enping

The low-resistance oil reservoirs in the Enping North Slope Oilfield Group exhibit substantial reserves and demonstrate significant development potential. However, their complex genetic mechanisms have hindered efficient exploitation. This study, focusing on the A Oilfield in the Enping Sag, integrates core thin-section analysis, well-logging data, and laboratory analytical data to systematically unravel the microscopic origins and dominant controlling factors of these reservoirs. The results classify the low-resistance reservoirs into two distinct types: (1) thin sand-mud interbeds with highly saline formation water (HJ61 layer), where low resistivity is governed by formation water salinity (>40,000 mg/L) and sand-mud interlayer interactions; (2) high-shale-content reservoirs with elevated bound water saturation (ZJ32 layer), primarily influenced by complex pore structures and high clay mineral content (>25%). Nuclear magnetic resonance (NMR) logging effectively identifies bimodal T2 spectrum characteristics of low-resistance reservoirs. By combining sedimentary facies analysis with seismic attribute prediction, this approach optimizes horizontal well trajectory design, significantly enhancing reserve utilization efficiency. The study provides theoretical insights and technical strategies for the exploration and development of low-resistance oil reservoirs in the Pearl River Mouth Basin.