Research Institute of Unconventional Oil & gas and New Energy, China University of Petroleum (East China), Qingdao, Shandong, China.
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology), Chengdu, Sichuan, China.
PLoS One. 2018 Jun 27;13(6):e0199283. doi: 10.1371/journal.pone.0199283. eCollection 2018.
The Lower Silurian Longmaxi Shale in Southeast Chongqing of Sichuan Basin in China is considered to be a potential shale gas reservoir by many scholars in recent years. The special shale gas well, namely, Pengye-1 well, was selected as a case study to evaluate the characteristics of the shale gas reservoir. A series of experiments were performed to analyze the geochemical, mineralogical, and petrophysical features and gas content using samples of the Longmaxi Shale from Pengye-1 well. The results show that the organic and inorganic porosities of these samples are range of 0.08-2.73% and 0.06-2.65%, with the average of 1.10% and 1.76%, respectively. The inorganic pores primarily contribute to the porosity until the TOC content is more than 3%. Organic matter plays an important role in adsorbed gas content. The adsorbed gas is dominant in the Longmaxi Shale of Pengye-1 well, which ranges from 0.46 to 2.24 cm3/g, with an average of 1.38 cm3/g. The free gas content ranges from 0.45 to 0.84 cm3/g with an average of 0.68 cm3/g, and is 24.4-49.7 percent of total gas with an average of 37.5%. The bottom part of the Longmaxi Shale is the most favorable for shale gas exploring, which is higher of brittleness mineral content, porosity and gas content. Compare with the other five shales in America, the Lower Silurian Longmaxi Shale is derived from older sedimentary periods with significantly higher thermal maturity and has experienced several periods of intense tectonic, which are unfavorable for the shale gas enrichment.
近年来，中国四川盆地东南地区的下志留统龙马溪页岩被许多学者认为是一种潜在的页岩气储层。本文选取龙马溪组特有的页岩气井——彭页 1 井作为研究案例，对其页岩气储层特征进行评价。通过对取自彭页 1 井的龙马溪组页岩岩心样品进行一系列实验，分析了其地球化学、矿物学和岩石物理特征及含气量。结果表明，这些样品的有机孔和无机孔的范围分别为 0.08%-2.73%和 0.06%-2.65%，平均值分别为 1.10%和 1.76%。在 TOC 含量大于 3%之前，无机孔隙主要贡献于总孔隙度，而有机碳则对吸附气含量起着重要作用。龙马溪组页岩以吸附气为主，范围为 0.46-2.24cm3/g，平均值为 1.38cm3/g。游离气含量范围为 0.45-0.84cm3/g，平均值为 0.68cm3/g，占总气量的 24.4%-49.7%，平均值为 37.5%。龙马溪组页岩的底部最有利于页岩气勘探，该区域脆性矿物含量、孔隙度和含气量均较高。与美国的另外五个页岩相比，下志留统龙马溪页岩的沉积时代更老，热演化程度更高，经历了多次强烈的构造运动，这些因素都不利于页岩气的富集。
