北部湾盆地复杂低渗储层品质分级表征 

Classification and characterization of complex low-permeability reservoir quality in Beibuwan Basin

张冲 杨朝强 汪新光 赵楠 彭小东

中海石油（中国）有限公司海南分公司，海南 海口570312

Hainan Branch of CNOOC Ltd., Haikou 570312, China

为精细刻画北部湾盆地低渗砂砾岩储层品质差异，通过引入储层品质指数作为表征储层品质差异的中间桥梁，利用岩心核磁共振实验测得的T2弛豫时间谱分布，构建了能反映各级别孔隙配置特征的储层品质评价新参数——可动流体优势贡献比。高压压汞分析求取的结构系数与可动流体优势贡献比具有显著相关性，可动流体优势贡献比越小，结构系数越大，验证了可动流体优势贡献比表征孔隙结构差异的可靠性。利用启动压力梯度变化率数量级，结合核磁曲线形态特征，确定了北部湾盆地低渗储层的品质级次。在此基础上，基于快速聚类法得到了低渗储层品质分级界限，并通过灰色关联数据分析法确定了各储层品质评价参数的权值。融合储层品质核心表征参数，构建了海上低渗油藏渗流能力品质的综合评价因子，从而量化和表征了北部湾盆地低渗砂砾岩的储层品质。

In order to accurately characterize the quality difference of low-permeability glutenite reservoirs in Beibuwan Basin, the reservoir quality index was introduced as an intermediate bridge to characterize the difference of reservoir quality. The T2 spectrum distribution measured by core nuclear magnetic resonance experiment was used to construct a new parameter for reservoir quality evaluation: the dominant contribution ratio of movable fluid, which can reflect the characteristics of pore configuration at all levels. The structural coefficient obtained by high pressure mercury injection analysis was significantly correlated with the dominant contribution ratio of movable fluid. The smaller the dominant contribution ratio of movable fluid was, the larger the structural coefficient was， which verified the reliability of the dominant contribution ratio of movable fluid to characterize the difference in pore structure. The quality grades of low-permeability reservoirs in Beibuwan Basin was determined by using the order of magnitude of the change rate of starting pressure gradient and combining with the morphological characteristics of nuclear magnetic resonance curves. On this basis, the classification boundary of low-permeability reservoir quality is determined based on the fast clustering method, and the weight of each reservoir quality evaluation parameter is determined by the grey correlation data analysis method. The comprehensive evaluation factor of seepage capacity quality of offshore low-permeability reservoir is constructed by integrating the key characterization parameters of reservoir quality, so as to quantify and characterize the reservoir quality of low-permeability glutenite in Beibuwan Basin.

10.6056/dkyqt202204008