脉冲中子全谱饱和度测井技术在高水淹油藏中的应用研究

Study on the Application of Pulsed Neutron Full-Spectrum Saturation Logging Technology in Highly Waterflooded Reservoirs

摘要: 针对东部老油田开发中后期挖潜的难题，本文深入研究了脉冲中子全谱饱和度测井技术的物理基础、技术优势及工程应用价值。该技术基于先进的中子–伽马能谱分析原理，通过创新性地融合非弹性散射与热中子俘获双谱信息进行反演解释，有效克服了油藏高水淹后地层水矿化度多变、孔隙结构复杂化等因素对传统测井方法计算含油饱和度的严重干扰。研究以江苏油田典型高水淹区块为例，通过系统性的现场测井数据与生产动态、岩心分析等数据的多源信息融合与对比分析，验证了该技术在划分水淹层、识别低阻油层、寻找剩余油富集层段方面的卓越能力。研究结果表明，通过构建多参数交会图版与响应特征模型，该技术能够有效识别弱、中、强不同等级的水淹层，并对未解释层段进行准确判别。最终，该技术为高含水后期油藏的措施挖潜(如补孔、堵水、压裂)及开发层系、井网的调整提供了精准可靠的依据。

Abstract: Addressing the challenge of precisely evaluating remaining oil saturation in highly waterflooded reservoirs, this paper conducts an in-depth study of the physical principles, technical advantages, and engineering application value of pulsed neutron full-spectrum saturation logging technology. Based on advanced neutron-gamma spectroscopy analysis principles, this technology innovatively integrates dual-spectrum information (inelastic scattering and thermal neutron capture) for inversion interpretation. This effectively overcomes the severe interference caused by varying formation water salinity and complex pore structure after severe waterflooding, which hampers traditional logging methods in calculating oil saturation. Using a typical highly waterflooded block in the Jiangsu Oilfield as a case study, the research systematically integrates and compares multi-source data, including field logging data, production performance data, and core analysis data. This validates the technology’s outstanding capabilities in distinguishing water-flooded zones, identifying low-resistivity oil layers, and locating remaining oil-enriched intervals. The results demonstrate that by constructing multi-parameter crossplots and response characteristic models, the technology effectively identifies water-flooded zones of different intensities (weak, moderate, strong) and accurately discriminates uninterpreted intervals. Ultimately, this technology provides precise and reliable guidance for potential tapping measures (such as reperforation, water shut-off, and fracturing) and adjustments to development layers and well patterns during the late high-water-cut stage of reservoirs.