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ORIGINAL RESEARCH article

Front. Earth Sci.
Sec. Geochemistry
Volume 12 - 2024 | doi: 10.3389/feart.2024.1421404

A TGA/DTA-MS investigation of the difference between organicrich and organic-free mudstones during pyrolysis process

Provisionally accepted
Pengyan Du Pengyan Du 1*Jingong Cai Jingong Cai 2*Huidong Li Huidong Li 3*Xuejun Zhang Xuejun Zhang 4*Juan Wang Juan Wang 4*Liping Yang Liping Yang 3*Yanzhong Zhen Yanzhong Zhen 5*
  • 1 Yan'an University, Yan'an, China
  • 2 State Key Laboratory of Marine Geology, Tongji University, Shanghai, Shanghai Municipality, China
  • 3 Shanghai Institute of Ceramics, Chinese Academy of Sciences (CAS), Shanghai, Shanghai Municipality, China
  • 4 Research Institute of Petroleum Exploration and Development, SINOPEC Shengli Oilfield Company, Dongying, Shandong, China
  • 5 School of Petroleum and Environmental Engineering, Yan'an University, Yanan, Shaanxi Province, China

The final, formatted version of the article will be published soon.

    Whether mudstone is rich in or free of organic matter has a great influence on the occurrence of water. Comparing different types of water in organic-rich and organicfree mudstones is helpful for further understanding the role of water in hydrocarbon generation. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) combined with mass spectrometry (MS) afford the opportunity to identify the mass change, reactions and products of the sample in a real-time monitored heating process.This study compared the pyrolysis characteristics of an organic-rich mudstone (CN1) and an organic-free mudstone (CW1) by using the TGA/DTA-MS method to estimate the content of different types of H2O and CO2 in organic-rich mudstones. The results show that the mass changes in CN1 and CW1 can be divided into the three thermogravimetric (TG) stages of 0-200℃, 200-650℃, and 650-900℃, while the peak temperatures of H2O and CO2 obtained through MS are different for CN1 and CW1. The differences in mineral components and organic matter between CN1 and CW1 suggest that the MS peaks of H2O and CO2 in CW1 are mainly influenced by clay and carbonate minerals, and that those of CN1 are also influenced by organic matter. In addition, quantification equations for CO2 and H2O contents from both the organic and inorganic origin of the organic-rich mudstone can be established by using the MS peak area of CO2 and H2O, mass loss in TGA and the mineral composition of the organic-free mudstone. This work provides useful insights for further understanding the hydrocarbon generation mechanism, as well as quantifying different types of water in organic-rich mudstones.

    Keywords: Organic-rich mudstone, Organic-free mudstone, quantification, H2O, CO2

    Received: 22 Apr 2024; Accepted: 09 Jul 2024.

    Copyright: © 2024 Du, Cai, Li, Zhang, Wang, Yang and Zhen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Pengyan Du, Yan'an University, Yan'an, China
    Jingong Cai, State Key Laboratory of Marine Geology, Tongji University, Shanghai, 200092, Shanghai Municipality, China
    Huidong Li, Shanghai Institute of Ceramics, Chinese Academy of Sciences (CAS), Shanghai, 200050, Shanghai Municipality, China
    Xuejun Zhang, Research Institute of Petroleum Exploration and Development, SINOPEC Shengli Oilfield Company, Dongying, Shandong, China
    Juan Wang, Research Institute of Petroleum Exploration and Development, SINOPEC Shengli Oilfield Company, Dongying, Shandong, China
    Liping Yang, Shanghai Institute of Ceramics, Chinese Academy of Sciences (CAS), Shanghai, 200050, Shanghai Municipality, China
    Yanzhong Zhen, School of Petroleum and Environmental Engineering, Yan'an University, Yanan, 716000, Shaanxi Province, China

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