Abstract:

Natural gas hydrate is generally considered to be one of the most promising new type of clean energies to replace coal, oil and natural gas, and it has enormous reserves but still untapped. Guangzhou Marine Geological Survey carried out geophysical, geochemical and comprehensive geological investigation in the northern slope of the South China Sea from the year of 1999, obtained a lot of geological information about gas hydrate occurrence, and implemented drilling in year 2007 in the Shenhu area and in year 2013 in the eastern part of the Pearl River Mouth Basin; both of them acquired gas hydrate samples successfully, especially the voyage of drilling in year 2013 in the eastern part of the Pearl River Mouth Basin had gotten high purity, new type of gas hydrate samples. The result of above investigation and drilling confirmed the existence of a huge resource prospects of gas hydrate in South China Sea. This paper gives a brief introduction of the main results of the drilling in year 2013 in the eastern part of the Pearl River Mouth Basin. This study makes contrastive analysis between several hydrate drilling areas worldwide and the accumulation condition in the eastern part of the Pearl River Mouth Basin before the drilling. The result indicated that gas source, stable environment, gas migration and reservoir conditions are essential factors of gas hydrate accumulation. According to the analysis of the characteristics of these factors, we forecasted the formation of seeped hydrate in this area. The drilling in year 2013 revealed the coexistence of the disseminated hydrate and seeped hydrate in this area and illustrated that the controlling factors of the formation and distribution of gas hydrate in this area were more complex.

Key words: the eastern part of the Pearl River Mouth Basin, the South China Sea, natural gas hydrate, key elements of accumulation, drilling