A Pressure and Temperature Preservation System for Gas-hydrate-bearing Sediments Sampler
Zhu, HY; Liu, QY*; Wong, G; Xiao, XH; Zhu, XH; Jiang, ZL; Zhang, DY
A pressure and temperature preservation system (PTPS) was developed for a natural gas hydrates (NGH) sampler. First, some pressure-coring tools for gas hydrate and free gas investigation are reviewed. Then a PTPS with length of 11.2 m and diameter of 60 mm was developed, which can be divided into four parts with a length of less than 4 m for each part. Laboratory experiments showed that this new PTPS was suitable for maintaining the pressure and temperature of ice and water mixture. Further, this new PTPS was applied during the HY4-2006-03 voyage of No. 4 ocean ship on the northern part of the South China Sea, and two pressurized sediments of 85 and 100 cm length were obtained. All laboratory experiments and applications show that the maximum operating depth and sample length of this PTPS are 3,000 m and 10 m, respectively, the PTPS has a good ability of recovering sediment samples on the seafloor and maintaining their original in situ pressure and temperature, meeting the requirement of exploration of NGH in deep-sea shallow sediment layers.