抄録
Exploration for natural methane hydrate was carried out in the Nankai-Trough offshore Japan at a water depth of 945m over an 88 day period, from November 1999 to February 2000. This was a national project led by Ministry of International Trade and Industry (MITI) to seek a new energy source. It was organized by Japan National Oil Corporation (JNOC) in collaboration by Japan Petroleum Exploration Co., Ltd as the drilling operator. The Nankai-Trough well was drilled with R & B Falcon's deepwater semisubmersible, the “M. G. Hulme, Jr.”. The location was selected where BSR (Bottom Simulating Reflector) is the clearest on the seismic section. Six wells within 100m distances were drilled through the BSR horizon and the hydrate rich formation was confirmed between 1, 135m to 1, 213m BMSL (below mean sea level). This paper describes the planning, preparatory phase and the challenging operations.
