基于NLDFT模型的渝东五峰组页岩孔隙结构特征及其储气意义

发布时间：2018-03-30 03:24

本文选题：页岩气　切入点：矿物组成　出处：《地球化学》2017年06期

【摘要】：页岩储层微观孔隙结构特征的研究对页岩气的资源评价和成藏机理研究均具有重要的意义。前人在研究页岩的孔隙特征时常采用针对不同孔径范围孔隙特征的表征方法和模型的简单拼接,但上述不同方法拼接使用对页岩在整体孔径范围内的孔径分布特征的刻画不够准确。本文选取10个渝东石柱地区五峰组页岩作为研究对象,测定了其总有机碳(TOC)及矿物组成,并对比了二氧化碳-氮气吸附的非限定域(NLDFT)模型及限定域(DFT)模型的比表面积、孔体积等参数,探讨了页岩的孔隙结构及其对页岩气储存方面的意义。结果表明,页岩脆性矿物含量很高,脆性指数介于0.52~0.88之间,平均为0.71,页岩具有良好的可压裂性。微孔提供了用于吸附页岩气的最主要的比表面积,其比表面积为18.27 m2/g,占总比表面积的81.61%,是页岩气的最重要的吸附场所;介孔及宏孔的平均孔体积为22.51×10 3 cm3/g,占了总孔体积的81.48%,是游离态页岩气的重要储存空间。渝东石柱地区页岩吸附气含量要比先前评价中的含量有着很大比例的升高,游离气的含量比先前评价中的含量要略高一些。
[Abstract]:The study of pore structure characteristics of shale reservoir is of great significance to the evaluation of shale gas resources and the study of reservoir formation mechanism. Simple splicing of methods and models, However, the characteristics of pore size distribution in the whole pore size range of shale are not accurately described by using the different splicing methods mentioned above. In this paper, 10 shale rocks of Wufeng formation in Shizhu area of eastern Chongqing were selected as research objects, and their total organic carbon (TOC) and mineral composition were determined. The specific surface area and pore volume of the unqualified NLDFT- model and the DFT- model are compared, and the pore structure of shale and its significance to shale gas storage are discussed. The brittle mineral content of shale is very high, the brittleness index is between 0.52 ~ 0.88 and the average value is 0.71. The shale has good fracturing ability. The micropore provides the most important specific surface area for adsorbing shale gas. Its specific surface area is 18.27 m2 / g, accounting for 81.61% of the total specific surface area, which is the most important adsorption site for shale gas. The average pore volume of mesoporous and macro pores is 22.51 脳 10 ~ (3) cm ~ (-3) / g, accounting for 81.48% of the total pore volume, which is an important storage space for free shale gas. The content of free gas is slightly higher than that in the previous evaluation.
【作者单位】：中国科学院广州地球化学研究所有机地球化学国家重点实验室;中国科学院大学;
【基金】：中国科学院战略性先导科技专项(B)(XDB10010502)
【分类号】：P618.13

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