鄂尔多斯盆地致密砂岩的核磁共振响应特征及影响因素

发布时间：2018-03-04 01:07

本文选题：致密砂岩　切入点：核磁共振　出处：《西安石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：鄂尔多斯盆地致密砂岩储层分布范围广,资源量丰富,是勘探的重点。核磁共振技术以其独特的优势在储层评价方面应用广泛。本文利用核磁共振、电镜扫描影像、铸体薄片、X-衍射、高速离心等技术,针对取自研究区的56块致密油岩心和17块致密气岩心开展了可动流体实验。首先,对实验参数进行了优化。优选出核磁共振测试参数:扫描次数64,等待时间5s,回波个数6000,回波间隔0.27ms。还分析了不同的离心力和离心时间下的岩心含水饱和度和T2谱变化规律,确定出致密油、气岩心的最佳离心时间为3h,离心力分别为2.07MPa和2.78MPa,对应有效渗流喉道半径下限为0.070μm、0.052μm。喉道半径大于该值的孔隙中赋存可动流体,该结论可为今后致密储层评价提供参考。其次,分析实验岩心T2谱特征,饱和状态下T2分布主要为双峰左高右低型,少数呈单峰或三峰,有效信号在0.1~1000ms内。离心后T2分布主要为单峰,分布范围为0.1~100ms。可动峰基本消失,不可动峰降低幅度小。岩心物性越差,离心前后T2谱间隔越小,可动水含量越少。最后,研究可动流体T2截止值和可动流体参数变化规律及其影响因素。整体上分布分散,数值偏低。致密油、气岩心的T2截止值的平均值分别为6.509ms、3.767ms,可动流体饱和度平均值为31.711%、28.304%,可动流体孔隙度平均值为2.149%、2.230%。多数储层属于中等甚至较差储层。影响因素主要包括储层物性、孔隙类型、粘土矿物等微观孔隙结构因素及元素组成等。
[Abstract]:The tight sandstone reservoir in Ordos Basin is widely used in reservoir evaluation because of its wide distribution and abundant resources. Nuclear magnetic resonance (NMR) technology is widely used in reservoir evaluation with its unique advantages. In this paper, nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM) are used to evaluate the reservoir. The movable fluid experiments were carried out on 56 dense oil cores and 17 dense gas cores obtained from the study area by casting thin slice X-ray diffraction, high-speed centrifugation and other techniques. The experimental parameters were optimized. The parameters of nuclear magnetic resonance (NMR) were selected as follows: scanning number 64, waiting time 5 s, echo number 6 000, echo interval 0.27 Ms. The variation of water saturation and T 2 spectrum of core under different centrifugal force and centrifuge time were also analyzed. The optimum centrifugal time of gas core is 3 h, the centrifugal force is 2.07 MPA and 2.78 MPA, respectively, corresponding to the lower limit of effective percolation throat radius is 0.070 渭 m ~ 0. 052 渭 m. This conclusion can be used as a reference for the evaluation of tight reservoirs in the future. Secondly, the characteristics of T 2 spectrum of experimental cores are analyzed. Under saturation condition, T2 distribution is mainly of double peaks, left high, right low, and a few of them are single or triple peaks. The effective signal is within 0.1 ~ 1000ms. After centrifugation, T2 distribution is mainly a single peak, and the distribution range is 0.1 ~ 100ms.The movable peak basically disappears, and the immovable peak decreases slightly. The worse the physical properties of the core, the smaller the T _ 2 spectrum interval before and after centrifugation, and the less the movable water content. Finally, The variation of T 2 cutoff value of movable fluid and movable fluid parameters and its influencing factors are studied. The whole distribution is dispersed, the value is low, and the oil is dense, The average T _ 2 cutoff values of gas cores are 6.509ms / 3.767msrespectively, the mean value of movable fluid saturation is 31.711m / 28.304m, and the mean value of movable fluid porosity is 2.149- 2.230. most of the reservoirs belong to medium or poor reservoirs. The influencing factors mainly include reservoir physical properties and pore types. Clay minerals and other micro-pore structure factors and element composition.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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