• Method for Measuring pH and Alkalinity of High-Pressure Fluid Samples : Evaluation through Artificial Samples
  • Minseok Song·Soohyeon Moon*·Gitak Chae·Jun-Hwan Bang

  • Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon 34132, Korea

  • 고압 유체 시료의 pH 및 알칼리도 측정 방법 : 가상 시료를 활용한 실용성 평가
  • 송민석·문수현*·채기탁·방준환

  • 한국지질자원연구원

  • This article is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


As part of monitoring technology aimed at verifying the stability of CO2 geologic storage and mitigating concerns about leakage, a method for measuring the pH and alkalinity of high-pressure fluid samples was established to obtain practical technology. pH measurement for high-pressure samples utilized a high-pressure pH electrode, and alkalinity was measured using the Gran titration method for samples collected with a piston cylinder sampler (PCS). Experimental samples, referencing CO2-rich water and CO2 geologic storage studies, were prepared in the laboratory. The PCS controls the piston, preventing CO2 degassing and maintaining fluid pressure, allowing mixing with KOH to fix dissolved CO2. Results showed a 6.1% average error in high-pressure pH measurement. PCS use for sample collection maintained pressure, preventing CO2 degassing. However, PCS-collected sample alkalinity measurements had larger errors than non-PCS measurements, limiting PCS practicality in monitoring field settings. Nevertheless, PCS could find utility in pre-processing for carbon isotope analysis and other applications. This research not only contributes to the field of CCS monitoring but also suggests potential applications in studies related to natural analogs of CCS, CO2-rock interaction experiments, core flooding experiments, and beyond.

Keywords: CCS monitoring, High-pressure fluid, High-pressure pH, Alkalinity, Piston cylinder sampler

This Article

  • 2024; 29(1): 1-9

    Published on Feb 29, 2024

  • 10.7857/JSGE.2024.29.1.001
  • Received on Dec 28, 2023
  • Revised on Jan 14, 2024
  • Accepted on Jan 31, 2024

Correspondence to

  • Soohyeon Moon
  • Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon 34132, Korea

  • E-mail: munarang@naver.com