海洋浅表层天然气水合物地质取样技术及样品现场处置方法

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

天然气水合物地质调查中通常采用地质、地球物理、地球化学等多种调查方法获得各类地质资料,而海洋地质取样可直接获得海底实物样品,是海洋地质调查中的重要手段。浅表层天然气水合物赋存于近海底沉积物中,利用合适的地质取样方法,在勘探目标区可以直接获得水合物样品及其存在的标志。基于浅表层水合物的存在指示标志和赋存特征,结合前期调查的成功经验,总结了适用于浅表层水合物的地质取样技术方法,主要有海底表层取样、重力柱状取样、海底钻探和保温保压取芯等,不同的取样方法所取的样品类型也有差异,应根据实际地质特征做出优选。针对浅表层天然气水合物的赋存特征,建立了一套海洋天然气水合物取芯样品现场处理和分析方法。水合物采集样品回收到甲板后快速处置分析是水合物调查的重要环节,而正确的现场处理方法是保证样品测试准确的关键。

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.