摘要
安棚深层系砂岩储层为特低孔特低渗透储层,发育微纳米级孔喉,储层物性规律性差,流体渗流特征复杂,储层定位和评价难度大。对目标层系砂岩进行饱和水核磁共振测量,并将T_2谱与其压汞曲线对比分析,应用最小二乘法拟合得出T_2弛豫时间与孔喉半径的转换参数,求得目标层系的岩心核磁孔喉分布及核磁孔喉参数,并结合核磁T_2分布与分形理论,计算了核磁孔喉分形维数,分析了各孔喉参数与渗透率的关系。结果表明,目标层系的孔喉分布呈双峰特征,相比压汞孔喉分布,核磁共振测量能获取更全面的孔喉信息;渗透率大于1×10^(-3)μm^2时孔喉半径主要分布在0.1~10μm的范围内,渗透率小于1×10^(-3)μm^2时孔喉半径主要分布在0.001~0.1μm的范围内;核磁T_2分布在一定的T_2区间内表现出分形特征;分形维数、核磁主流喉道半径、平均孔喉半径及中值半径均与储层的渗透率呈幂函数关系。
The sandstone reservoir in the deep series of strata in Anpeng area is considered as ultra - low porosity and permeability reservoir wit h nanometer and micrometer pores, the regularity of reservoir physic properties is poor, the flow characteristics of the fluid are complex, and the classification and evaluation of the reservoir are difficult. Nuclear magnetic resonance （NMR） measurements were performed on the saturated water cores.By comparing ob-T2spectrum with mercury intrusion curve, the conversion coefficients of T2relaxation time and throat radius were ob-tained by the least squares method and the pore-throat size distributions of cores were obtained. Based on NMR T2 distribution and fractal theory, the fractal dimension of pore-throat is calculated and the relationship between pore-throat parameters and permeability is analyzed. The results showed that the pore-throat size distributions show bi-modal characteristics, compared with the distribution of pore-throat size obtained by mercury intrusion,the NMR measurements can obtain the pore structure more comprehensively. The pore-throat radius is mainly distributed inthe range of 0. 1 -10 μm and range of 0. 001 -0. 1 μm when the permeability is more than 1 × 10^-3 μm^2 and less than 1×10^-3μm^-3 respectively . NMR T2 distribution shows fractal characteristics in a certain T2 in T2 terval,and the fractal dimension, the mainstream throat radius, the average pore-throat radius and the median radius are all related to the permeability of the reservoir in the form of a power function.
作者
刘峥君
李爱芬
周永强
韩文成
黎明
苏剑红
LIU Zheng-jun;LI Ai- fen;ZHOU Yong-qiang;HAN Wen-cheng;LI Ming;SU Jian-hong(Exploration and Development Research Institute,Henan Oilfield Branch,Sinopec1,Nanyang 473132,China;Petroleum Engineering,China University of Petroleum（East China）2,Qingdao 266580,China)
出处
《科学技术与工程》
北大核心
2018年第21期48-55,共8页
Science Technology and Engineering
基金
国家自然科学基金(51504276
51504277)
山东省自然科学基金(ZR2014EL016
ZR2014EEP018)资助
关键词
致密砂岩
核磁共振
高压压汞
孔喉分布
渗透率
分形维数
tight sandstone
nuclear magnetic resonance （NMR）
high-pressure mercury intrusion pore-throat size distribution
permeability
fractal dimension
