致密油储层孔隙结构核磁共振测井评价方法

对吉木萨尔凹陷芦草沟组致密油储层孔隙流体分布、微观润湿性和流体弛豫性质的分析认为,致密油储层的小孔隙主要含水且亲水,大孔隙主要含油且亲油。依据核磁共振测井T2谱评价孔径分布的公式、亲水孔隙表面弛豫率和亲油孔隙表面弛豫率的大小,将水弛豫信号和油弛豫信号分别转换为含油孔径和含水孔径分布,二者相加得到岩石总的孔径分布。通过对核磁共振测井资料的处理及其与岩心分析资料的对比分析,验证了本方法的有效性和可靠性。

Evaluation of pore structure using NMR logs for tight oil reservoirs

Analyzing the porefluids distribution,microscopic wettability and relaxation properties of fluids in tight oil reservoirs of Lucaogou Formation,Jimusaer Sag,Junggar Basin,it is believed that the relative small pore is mainly water-wet and saturated with water and that the relative big pore is mainly oil-wet and saturated with oil.The water and oil pore size distributions are transferred from the water and oil relaxation components by using different relaxivities and the equation for T2 distribution and pore size distribution.The pore size distributions are the sum of the water and oil pore size distributions.Comparing the pore size distributions from NMR logs and the core samples,the result verifies the proposed method for its effectiveness and reliability.