A FIELD STUDY ON THE EXPLORATION OF NATURAL GAS HYDRATE IN ULLEUNG BASIN OF KOREA

摘要

Recently, several advanced countries have been conducting projects to explore and develop natural gas hydrate which is one of the new energy resources for the future. In Korea, a five-year national project was initiated by KOGAS (Korea Gas Corporation) in the year 2000 with the sponsorship of MOCIE (Ministry of Commerce, Industry, and Energy) of Korea. This study aims to confirm the potential of natural gas hydrates and its location. To this point, for three years from 2000 to 2002, KOGAS surveyed the area of about 25,125 km km2 in East Sea with seismic research vessel TAMHAE II, and obtained promising results that indicated strong possibilities of the existence of natural gas hydrates. Analysis of the survey results showed clear pictures of BSR (Bottom Simulating Reflector), gas columns, mounds, and pork-marks. In conducting geological and geochemical surveys for natural gas hydrate potential, 28 deep-sea core samples were taken in Ulleung Basin of East Sea. The core sediments mainly consisted of muddy sediments with silty sand, tephra, and ash layers. Analysis of the wet sediment samples from the seabed showed that the TOC (Total Organic Carbon) ranged from 1.27 to 7.3%, which is a favorable condition for natural gas hydrate formation. Furthermore, hydrocarbon gas was analyzed to be mostly methane, comprising more than 98%. In this study, we presented both results of seismic, geological, and geochemical surveys and possibilities of existences of natural gas hydrate in Korea. These results will be applied to the selection of drilling position to develop natural gas hydrates.