石油科学通报2026，Vol.11Issue(2)：429-441,13.DOI:10.3969/j.issn.2096-1693.2026.01.007
基于孔喉连通性约束的核磁共振渗透率计算方法—以渤中凹陷砂岩储层为例
Nuclear magnetic resonance permeability calculation method based on pore-throat connectivity constraints:A case study of sandstone reser-voirs in the Bozhong Sag
王培春 1崔云江 1李志愿 1张新宇 2肖立志 2廖广志2
作者信息
- 1. 中海石油(中国)有限公司天津分公司,天津 300459
- 2. 中国石油大学(北京)油气资源与工程全国重点实验室,北京 102249
- 折叠
摘要
Abstract
In strongly diagenetically altered low-to medium-permeability sandstone reservoirs,disconnected pores are widely developed,making it difficult for conventional nuclear magnetic resonance(NMR)-based permeability evaluation methods to accurately reflect the true seepage capacity of the reservoir.These methods generally use an empirical T2 cutoff to partition free fluid volume(FFV)and bound volume irreducible(BVI),and then estimate permeability using the classical Timur-Coates model.However,because they cannot effectively distinguish connected pores from disconnected pores,the predicted permeability is often systematically overestimated.To address this issue,this study proposes a pore-throat-connectivity-constrained method for determining the T2 cutoff and incorporates it into the Timur-Coates permeability calculation workflow.First,core NMR T2 spectra and high-pressure mercury intrusion capillary pressure data are jointly utilized and transformed into equivalent pore-size distribu-tions and cumulative distribution curves.By quantitatively analyzing the correspondence between these two types of curves,the volume of disconnected pores and the associated critical pore-size range are identified,thereby determining a free-fluid T2 cutoff with clear physical significance.Based on this cutoff,FFV and BVI are reclassified and then substituted into the Timur-Coates model to recalculate permeability.A case study from sandstone reservoirs in the Bozhong Sag,Bohai Bay Basin,demonstrates that the proposed method effectively reduces the interference of disconnected pores in FFV estimation and transforms the T2 cutoff from an empirical selection into a quantitatively determined parameter constrained by pore-throat connectivity.Compared with the conventional empirical cutoff method,the proposed approach yields permeability predictions that are in much better agreement with measured core permeability,with the logarithmic root mean square error reduced from 1.079 to 0.104.These re-sults indicate that the proposed method significantly improves the accuracy and stability of permeability evaluation in reservoirs affected by complex diagenesis,and provides a more geologically meaningful and practically valuable approach for the refined permeability characterization of low-permeability complex sandstone reservoirs.关键词
孔喉连通性/渗透率/核磁共振/毛管压力实验/碳酸盐岩胶结物Key words
pore-throat connectivity/permeability/nuclear magnetic resonance/mercury intrusion capillary pressure/carbonate cementation分类
天文与地球科学引用本文复制引用
王培春,崔云江,李志愿,张新宇,肖立志,廖广志..基于孔喉连通性约束的核磁共振渗透率计算方法—以渤中凹陷砂岩储层为例[J].石油科学通报,2026,11(2):429-441,13.
