Petroleum Engineering and Geological Sciences Division, Rajiv Gandhi Institute of Petroleum Technology, Jais, Amethi, 229 304, India.
Geology Department, Faculty of Applied Science, Taiz University, 6803, Taiz, Yemen.
Sci Rep. 2020 Dec 17;10(1):22108. doi: 10.1038/s41598-020-78906-x.
A high bituminous shale horizon from the Gurha mine in the Bikaner sub-basin of the Rajasthan District, NW India, was studied using a collection of geochemical and petrological techniques. This study investigated the nature and environmental conditions of the organic matter and its relation to the unconventional oil-shale resources of the bituminous shale. The analyzed shales have high total organic carbon and total sulfur contents, suggesting that these shale sediments were deposited in a paralic environment under reducing conditions. The dominant presence of organic matter derived from phytoplankton algae suggests warm climatic marine environment, with little connection to freshwater enhancing the growth of algae and other microorganisms. The analyzed bituminous shales have high aquatic-derived alginite organic matters, with low Pr/Ph, Pr/n-C, and Ph/n-C ratios. It is classified as Type II oil-prone kerogen, consistent with high hydrogen index value. Considering the maturity indicators of geochemical T (< 430 °C) and vitrinite reflectance values less than 0.40%VRo, the analyzed bituminous shale sediments are in an immature stage of the oil window. Therefore, the oil-prone kerogen Type II in the analyzed bituminous shales has not been cracked by thermal alteration to release oil; thus, unconventional heating is recommended for commercial oil generation.
来自印度拉贾斯坦邦比卡内尔子盆地古尔哈矿区的高沥青质页岩层，使用一系列地球化学和岩石学技术进行了研究。本研究调查了有机质的性质和环境条件及其与沥青质页岩非常规油页岩资源的关系。分析的页岩具有高总有机碳和总硫含量，表明这些页岩沉积物是在还原条件下的滨海环境中沉积的。有机质主要来源于浮游植物藻类，表明温暖的海洋气候环境，与淡水的联系很少，有利于藻类和其他微生物的生长。分析的沥青质页岩具有高水生藻类有机物质，Pr/Ph、Pr/n-C 和 Ph/n-C 比值低。它被归类为 II 型产油潜力的干酪根，与高氢指数值一致。考虑到地球化学 T（<430°C）和镜质体反射率值小于 0.40%VRo 的成熟度指标，分析的沥青质页岩沉积物处于生油窗的未成熟阶段。因此，分析的沥青质页岩中 II 型产油潜力干酪根尚未通过热蚀变释放石油；因此，建议采用非常规加热来产生商业石油。
