【摘要】 刘堂宴 ,王绍民 ,傅容珊 ,周明顺 ,李艳华 ,罗曼 .核磁共振谱的岩石孔喉结构分析 .石油地球物理勘探 ,2 0 0 3,38(3) :32 8～ 333岩心核磁共振 T2 谱和压汞分析数据均在一定程度上反映了岩石的孔喉结构 ,理论分析表明 ,这两组数据具有相关性。应用岩心核磁共振 T2 谱研究岩石孔喉结构 ,关键是确定 T2 与 Pc的转换系数。但以前的方法在 T2与 Pc 的转换过程中 ,需要涉及某些岩石特性参数 ,实用中有一定困难。本文直接利用岩心核磁共振 T2 谱和压汞分析数据之间的相关性 ,客观地确定 T2 与 Pc之间的转换系数 ,避免了确定岩石特性参数的困难。应用本文方法 ,对 6块岩心的多种核磁共振分析数据进行了对比分析 ,做出了 NMR (Nuclear Magnetic Resonance,简称NMR) T2 毛管力曲线和孔喉半径分布 ,并将这些结果与压汞分析的结果进行了对比。结果表明 ,岩心 NMR T2谱在实用性和评价精度上均略显优势 ;至少是在饱含油的条件下 ,岩心的 NMR T2 谱可以用于研究孔喉结构分布 ,油气的弛豫特性作为影响背景值存在 ,对于评价结果没有明显的影响 ;在全部 6块岩心中 ,T2 与 Pc 的转换系数位于 2 5 0 0～ 4 0 0 0μs· MPa之间。更多还原

【Abstract】 Both NMR T 2 spectra of core and mercury intrusion capillary pressure can be used to characterize pore throat structures of rock in some degree.Theoretical analysis reveals correlation between these two sets of data.Determining the transferring coefficient between T 2 and P c is the key step when NMR spectra are utilized to study rock pore throat structure.In earlier methods,some characteristic parameters of rock should be given in advance before transferring T 2 into P c,which is difficult to determine these parameters precisely in practice.By using directly correlation between NMR spectra and mercury intrusion capillary pressure,a new method is presented in this paper to determine the transferring coefficient objectively.As a result,all the difficulties determining rock parameters are avoided.With this new method,after comparison and analysis of calculated various NMR spectra in 6 rocks,NMR (Nuclear Magnetic Resonance is called NMR for short) T 2 capillary pressure curve and pore throat distribution are given,and the results are compared with the analysis of mercury intrusion capillary pressure.Our research shows that NMR T 2 spectrum of core holds a little predominance in practical application and evaluation precision.In saturated oil rock,NMR T 2 spectra of core can be still utilized to evaluate the distributions of pure throat,the relaxation character of oil gas exists as an influence background value, which may have limited effects on the evaluation results. The transforming coefficients of the 6 samples,ranging 2500 ~ 4000 μs×MPa are given in the paper.更多还原