Khangar Ranjit Gangadhar, Mendhe Vinod Atmaram, Kamble Alka Damodhar, Ranjan Das Piyush, Shukla Priyanka, Bannerjee Mollika, Varma Atul Kumar
Department of Applied Geology, Indian Institute of Technology (ISM), Dhanbad 826004, Jharkhand, India.
CSIR-Central Institute of Mining and Fuel Research, Dhanbad 826015, Jharkhand, India.
ACS Omega. 2021 Oct 21;6(43):28678-28698. doi: 10.1021/acsomega.1c03340. eCollection 2021 Nov 2.
The carbon-rich Barakar and Barren Measures shale beds of the Jharia basin were evaluated for variation in pore size, pore structure, and fractal dimensions. The shale core samples were obtained from exploratory boreholes drilled at the Jharia basin. The shale samples were analyzed for organo-inorganic composition by FTIR, pore size, and pore structure using BET low-pressure N adsorption and pore geometry through FE-SEM photographs. The shale samples have significant carbon-rich content and are intercalated-banded in nature. The pore structures were evaluated through N isotherms and validated by SEM images, revealing the mixed contribution of organo-inorganic matter in pore formations controlled by geochemical alteration, diagenesis, and mineral interaction. The rough internal surfaces of the pore were evaluated by categorizing them into fractals , , and . It is observed that the type of fractals is in abundance associated with mesopores. The positive trend of fractals with pore size, pore structure, depth, fixed carbon, and TOC suggests the influence of different parameters on the formation of pore internal rugged surfaces in shale beds. The FE-SEM images indicate shallow to deep pores with different pore structures with fair to good pore connectivity. In summary, the shale beds of Jharia have heterogeneous complex pore structures, a rough surface, and sorption mechanisms controlled by weathering/alteration, depositional conditions, and organo-inorganic content. In shale beds, gas storage and transport phenomena are directly related to pore size distribution, pore structure, and associated fractal dimensions. The calculated values using the proposed empirical models for porosity (EPO) and permeability (EPE) showed excellent linear correlation with the measured porosity (MPOc, = 0.8577) and permeability (MPEc, = 0.8577), which are close to measured values. The curve matching of EPO with MPOc and EPE with MPEc follows a similar path, validating the results and suitability of the models. Hence, the proposed models may be considered to estimate the porosity and permeability of shale and coal beds.
对贾里亚盆地富含碳的巴拉卡尔和巴伦梅asures页岩层的孔径、孔隙结构和分形维数变化进行了评估。页岩岩芯样本取自贾里亚盆地的勘探钻孔。通过傅里叶变换红外光谱仪（FTIR）分析页岩样本的有机-无机成分，使用BET低压氮吸附法分析孔径和孔隙结构，并通过场发射扫描电子显微镜（FE-SEM）照片分析孔隙几何形状。页岩样本富含碳，本质上是夹层带状的。通过氮等温线评估孔隙结构，并通过扫描电子显微镜图像进行验证，揭示了在地球化学蚀变、成岩作用和矿物相互作用控制下，有机-无机物质在孔隙形成中的混合贡献。通过将孔隙的粗糙内表面分类为分形 、 和 来进行评估。观察到 型分形大量存在于中孔中。分形与孔径、孔隙结构、深度、固定碳和总有机碳（TOC）的正相关趋势表明不同参数对页岩层孔隙内部粗糙表面形成的影响。FE-SEM图像显示了具有不同孔隙结构、孔隙连通性良好至中等的浅孔到深孔。总之，贾里亚的页岩层具有非均质性复杂孔隙结构、粗糙表面以及受风化/蚀变、沉积条件和有机-无机含量控制的吸附机制。在页岩层中，气体储存和传输现象与孔径分布、孔隙结构和相关分形维数直接相关。使用所提出的孔隙率（EPO）和渗透率（EPE）经验模型计算的值与测量的孔隙率（MPOc， = 0.8577）和渗透率（MPEc， = 0.8577）显示出极好的线性相关性，接近测量值。EPO与MPOc以及EPE与MPEc的曲线匹配遵循相似路径，验证了模型的结果和适用性。因此，所提出的模型可用于估计页岩和煤层的孔隙率和渗透率。
