Nano-scale texture and porosity of organic matter and clay minerals in organic-rich mudrocks
Nano-scale texture and porosity of organic matter and clay minerals in organic-rich mudrocks
复制标题
DOI：
10.1016/j.fuel.2014.06.036
复制
发表时间：
2014-11-01
期刊：
影响因子：
7.4
通讯作者：
Prasad, Manika
中科院分区：
文献类型：
--
作者：
Kuila, Utpalendu;McCarty, Douglas K.;Prasad, Manika
石油和天然气页岩界对泥岩纳米级结构中有机质的形态和分布存在猜测。此外，微孔和中孔网络的存在，无论是完全存在于有机质中，还是作为孔隙系统存在于这些地层的矿物成分中，还没有得到很好的理解。关于埋藏成岩序列中有机质(OM)孔隙度随热成熟度的发展，已发表的定量数据很少。本文对波罗的海盆地埋藏序列中的孔隙大小分布(PSD)进行了对比研究，并选取了不同时代和成因的其他非常规油气藏的样品。方法包括X-射线衍射法(XRD)定量矿物分析、RockEval热解分析和77.3K下N-2的亚临界气体吸附(SGA)分析。对自然状态下的等分样品和用缓冲次氯酸钠(NaOCl)处理去除OM后的样品进行了分析，结果表明，粘土所含的微孔和介孔网络形成了纳米级的泥岩结构结构。有机质在粘土微观结构中的分布是不均匀的。有机质以单独的颗粒或片层形式存在，在那里粘土孔隙度可能会被吸附，或者OM可能部分或完全占据粘土集合体之间的空间。
Speculation exists in the oil and gas shale community about the form and distribution of the organic matter within the nanometer scale texture of mudrocks. In addition, the presence of micropore and mesopore networks either exclusively within the organic matter or as pore systems in the mineral components of these formations are not well understood. There is little published quantitative data with respect to the development of porosity in organic matter (OM) with thermal maturity in a burial diagenetic sequence. This paper presents a comparative study of pore-size distribution (PSD) in a burial sequence from the Baltic Basin, along with a selection of samples from other unconventional hydrocarbon reservoirs of various age and origin. Methods include quantitative mineral analysis by X-ray diffraction (XRD), RockEval pyrolysis, and subcritical gas-adsorption (SGA) analysis with N-2 at 77.3 K. SGA with N-2 is effective in quantifying the volume of small pores that are below the detection limit of imaging techniques. Analyses were performed on aliquot samples in the natural state and after OM removal by treatment with buffered sodium hypochlorite (NaOCl).The results indicate that the clay hosted micro-and mesoporous network forms the textural structure of mudrocks at the nanometer scale. The distribution of OM with respect to the clay microstructure is heterogeneous. OM exists as separate particles or laminations where clay porosity may be open to adsorption, or OM can partially or completely occupy the space between clay aggregates within dimensions