Abstract
This study focuses on the Joule–Thomson (J–T) valve of a low-temperature separator in a domestic offshore oil and gas field. To address the lack of systematic research on the existing control logic, a dynamic model consistent with field operating parameters was established using K-Spice software. The model was employed to simulate the impact of dry gas compressor shutdown on separator pressure and to optimize the J–T valve control strategy. The results indicated that under the original control logic, when one dry gas compressor was shut down due to a fault, the separator pressure rapidly increased to 82 barg within 10 s, triggering the high–high pressure alarm (PAHH) and causing production shutdown. After the control logic was improved, the J–T valve opening automatically decreased to 20% within 3 s once the compressor shutdown was detected. Under this condition, the separator pressure was effectively maintained below 82 barg, the PAHH alarm was avoided, and production continuity was ensured. Moreover, optimizing the separator temperature setpoint to − 20 °C reduced the risks of both degraded export gas quality and excessive flaring. Overall, the findings quantitatively describe the dynamic response of separator pressure to J–T valve adjustments and provide a valuable reference for improving J–T valve control logic in offshore oil and gas production systems.
Data availability
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
References
Ma, C. B., Huang, Z., Liu, X. D., Yang, Z. J. & Hu, D. Analysis and optimization of liquid level setting for three-phase separators based on K-Spice software. China Offshore Oil Gas. 33 (4), 172–178 (2021).
Ma, C. B., Liu, X. D., Liu, R. W., Cao, Y. & Huang, Z. Dynamic simulation of pressure setting for three-phase separators of offshore platforms based on K-Spice. Oil Gas Storage Transp. 40(12), 1401–1408 (2021).
Ma, C. B. et al. Study of well overpressure and pump circulation of an offshore oilfield by using K-Spice software. J. Beijing Inst. Petro-Chemical Technol. 28(4), 35–42 (2020).
Wen, K. et al. PID control of single-tube pump valve model based on K-spice and SPS. Gas Storage Transp. 38, 904–910 (2019).
He, L. et al. Study on supercritical CO₂ blowdown process for offshore platforms: A case study of BZ25-1 offshore platform. China Offshore Oil Gas. 35(4), 212–222 (2023).
Chen, G. J., Zhang, Y. D. & Ouyang, J. J. Optimization of desulfurization and decarbonization process of MDEA absorption tower in Amu river gas field. Contemp. Chem. Ind. 47(03), 558–562 (2018).
Xu, J. Comparative Analysis of Various Engineering Software on compressors (China University of Petroleum, Beijing, 2019).
Becquin, G., Castance, R. S., Abrol, S., Dober, D. & Jain, A. Glomsamker. Subsea multiphase boosting station system and controls optimization. World Oil (2015).
Havard, O., Biljana, D., Robert, D. G. & Hans, K. V. Model based multiphase metering and production allocation. Offshore Technology Conference (2014).
Oliver, B., Blair, M., Andrea, M. & Simon, H. Laggan-Tormore Pipeline Management System Rachael ferguson (Society of Petroleum Engineers, 2017).
Shoghl, S. N., Naderifar, A., Farhadi, F. & Pazuki, G. Thermodynamic analysis and process optimization of a natural gas liquid recovery unit based on the Joule-Thomson process. J. Nat. Gas Sci. Eng. 96, 104265 (2021).
Abeer, M., Ahmed, A., Mostafa, E., Nadia, A. & Tamer, F. Optimum operating conditions for improving natural gas dew point and condensate throughput. J. Nat. Gas Sci. Eng. 49, 324–330 (2018).
Kateryna, B. Model Free Optimal and Predictive Control of the K-Spice Process simulator (University College of Southeast Norway, 2016).
Zhang, M. Modelling Simulation and Control of the Last Stage of Natural Gas pipeline 41–50 (China University of Petroleum, Beijing, 2008).
Ji, L., Wang, X., Li, Z. G. & Li, R. Experimental study on the performance of new gas-liquid separator of natural gas. J. Eng. Therm. Energy Power 35(3), 116–121 (2020).
Kongsberg Digital. K-Spice User’s Manual 110–150 (Kongsberg Digital, 2025).
Acknowledgements
This study received support and funding from “Shenhai No.1” Intelligent Gas Field (Phase II) Construction Project / CNOOC Hainan Xinke [2023] No. 56.
Author information
Authors and Affiliations
Contributions
Y.L.: Conceptualization, Methodology, Writing—original draft. F.L. : Funding acquisition, Project administration, Investigation, Formal analysis, Writing—review & editing. G.Z.: Writing—review & editing. Z.Y.: Writing—review & editing.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Liu, Y., Lin, F., Zhu, G. et al. Analysis and optimization of the J–T valve control logic for offshore oil and gas field low-temperature separators based on K-Spice. Sci Rep (2026). https://doi.org/10.1038/s41598-026-35304-z
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-026-35304-z
