Investigation of the impact of threshold pressure gradient on gas production from hydrate deposits

Lu Cheng, Xuwen Qin, Chao Ma, Lu Yu* (Corresponding Author), Lantao Geng, Hang Bian, Keni Zhang, Yingfang Zhou* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Many hydrate-bearing sediments are featured with unconsolidated argillaceous
siltstones, which exist the non-Newtonian flow and threshold pressure gradient due to the high content of clay. In this study, the threshold pressure gradient of hydrate reservoir in the South China Sea is experimentally clarified. The quantitative relationship between it and the reservoir parameters is established. The function of threshold pressure gradient has been added into TOUGH+HYDRATE simulator. Here, site SH2, a candidate for field testing comprising a clayey silt gas hydrate reservoir in the Shenhu area of the South China Sea, was chosen to investigate the effect of threshold pressure gradient on gas production behavior through numerical simulations.The simulation results show that threshold pressure gradient has a significant impact on gas extraction. When the experimental value was applied, the gas production was
enhanced unexpectedly, where cumulative gas output doubled in 5 years. The active hydrate dissociating area (gas, water and hydrate coexist) has notably extended, accompanying with the expanding cool zone. Water blockage near well was relieved. However, with the increasing of threshold pressure gradient, propagation of pressure would be restrained seriously. The pressure and hydrate of far-field formations stay “frozen”. The bottom water invasion was weakened.
Original languageEnglish
Article number123569
Number of pages16
JournalFuel
Volume319
Early online date4 Mar 2022
DOIs
Publication statusPublished - 1 Jul 2022

Keywords

  • natural gas hydrate
  • Threshold Pressure Gradient (TPG)
  • argillaceous siltstones
  • numerical simulation

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