Formation and evolution of nanopores in organic-rich shales: Insights from the hydrous pyrolysis experiments in a closed system
| Autor: | Chuxiong Li, Xinchao Jiang, Qi Chen, Qilin Xiao |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | IOP Conference Series: Earth and Environmental Science. 360:012017 |
| ISSN: | 1755-1315 1755-1307 |
| Popis: | In order to make a better understanding of the formation and evolution process of nanopores in organic-rich shales with increasing thermal maturity, an early mature oil shale from the Nenjiang Formation in Changling Depression of Songliao Basin was pyrolyzed with the presence of brine water in a closed system. The measurements of TOC, XRD, N2 adsorption were conducted on the initial and pyrolyzed samples. The results show that the development of nanoporosity within pyrolyzed shales can be divided into three phases with thermal maturity increasing: the intensive increase (Ro=0.61-2.09%), slight decrease (Ro=2.09-2.47%) and slight increase (Ro=2.47-4.01%). The significant occurrence of nanopores was associated closely with intensive hydrocarbon generation and expulsion at the mature to high mature stages, liquid hydrocarbons filling into the nanopores restricts their developments. The formation of pyrobitumen by oil secondary cracking at the early over mature stage decrease the occurrence of micropores and macropores, and hence reducing the pore volumes. The secondary phase of nanopores formation is at the late over mature stage, which is attributed to the mineral transformation and limited capability of hydrocarbon generation and expulsion. This study should be helpful in evaluating shale oil and gas resources in nature. |
| Databáze: | OpenAIRE |
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