岩石激发极化弛豫时间谱实验研究

Experiment Research on Induced Polarization Spectrum of Rock

岩石的激发极化谱比岩石本身的极化率具有更丰富的信息。目前对激发极化现象的产生机理、极化特性等方面的研究还不够深入,对饱含丰富信息的极化谱的研究更少。以大量岩石激发极化实验和核磁共振实验数据为基础,应用阻尼最小二乘法实现了极化谱和T2的反演。分析了不同矿化度对极化谱的影响,对极化谱和T2谱进行了对比。岩石的激发极化时间衰减谱和T2谱在峰的个数和形态上都与T2谱有很好的相关性,二者又能同时反映孔喉结构。利用研究T2谱和岩石孔隙度、渗透率等参数之间的关系建立极化谱和这些参数之间的关系。通过研究,增强了对激发极化弛豫时间谱的认识,为激发极化测井提供有力的技术支持。

An Induced polarization spectrum of rock provides more information than the polarizability itself. Comparison on induced polarization relaxation time spectrum and nuclear magnetic resonance T2 spectrum of rock has been done. Experimental data of induced polarization and NMR of core samples are converted to polarization relaxation time spectra and NMR T2 spectra with Levenberg-Marquardt algorithm. The polarizability decreases following the increase of water salinity, but the position of the polarization spectrum peak is unchanged. The comparison of the polarization and T2 spectrum shows that the shapes of both spectra are rather similar, and both can reflect the pore throat structure of the rock.