摘要
建立了复杂储层的三维非规整网络模型,通过微观数值模拟研究了饱含水核磁T2谱与孔隙尺寸分布间的关系,讨论了储层特征及饱和度等对T2谱的影响规律。结果表明,饱含水岩样T2谱与孔喉半径分布具有很好的相似性,随着喉道半径、孔喉比的增大,核磁T2谱的峰值均向右移动,其不同之处在于:孔喉比增大时,孔隙体T2谱与喉道T2谱逐渐分开;含水饱和度为53%时,中等水湿岩样T2谱左边部分与水湿岩样基本重合,右边部分弛豫时间明显大于水湿岩样;油湿岩样的弛豫时间在整个区间内均大于水湿岩样;随着含水饱和度的降低,强水湿岩样T2谱峰值信号强度减弱,在左边短弛豫时间处出现另一缓慢增强的T2峰;中等水湿岩样T2谱原峰值处的信号强度降低,在右边长弛豫时间处出现一个以油的表面弛豫为主的峰。
A three-dimensional irregular network model was established for describing the porous structures of the complex reservoir. The relations between T2 spectra of nuclear magnetic resonance and the distribution of pore radius in water-saturated rock were studied by using numerical simulation. The effects of the reservoir properties and the saturation on T2 spectra were discussed. The resuits indicated that there was good correlation between the T2 spectra distribution and frequency histogram of pore radius. While increasing the throat radius and the ratio of pore to throat, the distribution peak of T2 spectra moved towards longer relaxation time. However, the superposition region of T2 spectra distribution between pore body and pore throat became smaller when the ratio of pore to throat increased. When the water saturation is 53%, the left part of the T, spectra for the intermediate-wet rock was almost superposed with that for the strongly water-wet rocks. The right part of the T2 spectra for the intermediate-wet rock was obviously larger than that for the strongly water-wet rock. The relaxation time of the oil-wet rock was longer than that of the strongly waterwet rock in the whole range, When the water saturation decreased, the intensity of the peak signal of the strongly water-wet rock reduced, and there was another peak at the left short T2 spectra. With the reduction of water saturation, the intensity of the original peak signal of the intermediate-wet rock decreased, and there was a peak at the right long T2 spectra mainly came from the surface relaxation of oil.
出处
《石油学报》
EI
CAS
CSCD
北大核心
2009年第3期422-426,共5页
Acta Petrolei Sinica
基金
国家科技重大专项“复杂油气藏测井综合评价技术、配套装备与处理解释软件”(2008ZX05020)资助
关键词
逾渗网络模型
核磁T2谱
孔隙结构
润湿性
饱和度
数值模拟
percolation network model
NMR T2 spectra
pore structure
wettability
saturation
numerical simulation
