To overcome the limitations of using a single T₂ cutoff value for characterizing fluid occurrence and mobility in reservoirs, a method based on multistage centrifugal nuclear magnetic resonance (NMR) experiments is proposed to determine multiple T₂ cutoff values. This method is used to identify fluid types and their distribution characteristics. Combined with constant‑rate mercury intrusion porosimetry and X‑ray diffraction (XRD) analysis, the pore structure and mineral composition of the reservoir are determined, and the occurrence characteristics and controlling factors of movable fluids in the multiscale pore spaces of unconventional reservoirs are investigated. The results indicate that the division method with multiple T₂ cutoff values further subdivides the types and occurrence spaces of movable fluids. The mobility evaluation can better reflect the development characteristics of micron‑nano pore throats and the mineral composition within the reservoir, and shows stronger adaptability to shale and tight sandstone reservoirs, which have more subtle pore structures and more complex mineral compositions. The occurrence characteristics of movable fluids are jointly controlled by three main factors: reservoir physical properties, mineral composition, and the uniformity of pore‑throat distribution.

shale reservoir, tight sandstone reservoir, nuclear magnetic resonance (NMR), movability evaluation; pore structure, occurrence characteristics

为规避单一弛豫时间(T₂)截止值划分储层内流体赋存特征及可动性的局限性, 提出一种基于多级离心核磁共振实验划分多T₂截止值的方法, 用来确定储层内的流体类型和分布特征, 结合恒速压汞实验、X射线衍射分析, 确定储层的孔隙结构和矿物组成, 探讨非常规储层多尺度孔隙空间内可动流体赋存特征及控制因素。结果表明, 多T₂截止值的划分方法进一步细分了可动流体类型及赋存空间, 可动性评价能更好地响应储层内微米–纳米孔喉发育特征及矿物组成特点, 对孔隙结构更加细微和矿物组成更加复杂的页岩以及致密砂岩储层的适应性更强; 可动流体赋存特征由储层物性、矿物组成以及孔喉分布的均匀程度这3个主要因素共同决定。