Geological sampling method and on-site processing of coring samples of marine shallow gas hydrate

In the geological survey of natural gas hydrate, various geological data are usually obtained by geological, geophysical, geochemical and other survey methods. Among them, marine geological sampling can directly obtain the physical samples of the seabed, which is an important means in marine geological survey. Shallow gas hydrate exists in near seabed sediments. Hydrate samples and their existence markers can be obtained directly in the exploration target area by using appropriate geological sampling methods. Based on the indicators and occurrence characteristics of shallow surface hydrate, combined with the successful experience of previous investigation, this paper summarizes the geological sampling methods suitable for shallow surface hydrate, mainly including seabed surface sampling, gravity column sampling, seabed drilling and thermal insulation and pressure maintaining coring. The types of samples taken by different sampling methods are also different, which should be optimized according to the actual geological characteristics. According to the occurrence characteristics of shallow gas hydrate, a set of on-site processing and analysis methods of marine gas hydrate coring samples are established. The rapid processing and analysis of hydrate samples after being recovered to the deck is an important link of hydrate investigation, and the correct on-site processing method is the key to ensure the accuracy of sample testing.