海洋砂质水合物研究进展、勘探流程和难点挑战

Research progress, exploration process, and challenges in marine sandy hydrates

樊奇 付强 郭刚 朱振宇 庞维新 李清平 卓海腾

FAN Qi FU Qiang GUO Gang ZHU Zhenyu PANG Weixin LI Qingping ZHUO Haiteng

1. 中海油研究总院有限责任公司, 北京 100028; 2. 海洋天然气水合物全国重点实验室, 北京 100028; 3. 中山大学 海洋科学学院, 广东 珠海 519082

1. CNOOC Research Institute, Beijing 100028, China; 2. State Key Laboratory of Gas Hydrate, Beijing 100028, China; 3. School of Marine Sciences, Sun Yat-Sen University, Zhuhai, Guangdong 519082, China

天然气水合物是海洋能源的重要开拓领域，但南海泥质粉砂型水合物的技术和经济门槛高、开发潜力争议大。梳理了近20年中国、美国、日本在海域砂质水合物勘探中取得的重要进展和观点，对3种主要水合物类型(泥质粉砂孔隙充填型、泥质粉砂裂隙充填型、砂质孔隙充填型)进行论述，结合实例梳理了砂质水合物在岩心、测井、实验角度的特点，介绍了“水合物成藏系统”的勘探评价步骤，讨论了非成岩储层评价、温度—压力变化、地质力学、保压取心等难题挑战。结果表明，砂质孔隙充填型水合物(可拓展至粉砂粒级)是目前唯一具备经济价值的水合物类型，具有饱和度高(40%～90%)、电阻率高、地层强度高、石英含量偏高(56%～77%)、粒度中值偏高(约56～87 μm)等特点，多为白灰色、黑灰色分选均匀的粉砂状沉积，有明显磨砂感，发育孔洞构造。应当加强“水合物成藏系统”在砂质水合物勘探中的推广应用，进一步攻关非成岩储层评价、温度—压力变化引起的相变、复杂的地质力学问题、保压取心技术等问题。重新审视水合物的资源价值，以期为“两气合采”工作提供理论基础和科学参考。

Natural gas hydrates are a key area of development in marine energy resources. However, the technical and economic barriers for muddy silt gas hydrate exploration in the South China Sea are high, and their resource potential remains controversial. This paper reviews the significant advancements achieved in China, the United States, and Japan over the past 20 years in the exploration of marine sandy hydrates. It discusses three primary hydrate types, i.e., muddy silt pore-filling, muddy silt fracture-filling, and sandy pore-filling hydrates, and summarizes the characteristics of sandy hydrates based on core samples, well logging, and laboratory findings. This paper presents the exploration and evaluation procedures for the “hydrate accumulation system” and discusses the challenges such as non-diagenetic reservoir evaluation, temperature-pressure variations, geomechanics, and pressure-preserved coring. Results reveal that sandy pore-filling hydrates (extendable to silt-sized particles) are currently the only hydrate type with economic value, characterized by high saturation (40% to 90%), high resistivity, strong formation strength, high quartz content (56% to 77%), and higher median particle size (approximately 56 to 87 μm). Those hydrates are typically well-sorted silty deposits in white-gray or black-gray, with a frosted texture and pore structure development. It is recommended to enhance the popularization and application of the “hydrate accumulation system” in the exploration of sandy hydrates and further address the issues in non-diagenetic reservoir evaluation, phase transitions due to temperature-pressure changes, complex geomechanical problems, and pressure-preserved coring technology. In conclusion, a reassessment of hydrate resource value is needed to provide a theoretical and scientific basis for the co-production of natural gas and gas hydrates.

中国海油海洋天然气水合物全国重点实验室主任基金(2024)、国家重点研发计划(2021YFC280090302)和国家自然科学基金企业联合项目(U20B6005)联合资助。

https://doi.org/10.11781/sysydz2025020235