| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an excavation technology effective for excavating methane hydrate sealed in a sea bottom stratum.SOLUTION: A whole constitution of a methane hydrate production facility consists of a platform (facility storing pontoon) installed on a sea, an excavation facility for performing mobile excavation in a sea bottom, a pipe connecting the pontoon and the excavation facility to each other and recovering methane hydrate, connection wires, a power cable and the like. The pontoon is equipped with a power unit, a high-pressure pump unit for excavation, a lifting winch for a sea bottom excavator, a separation facility and the like, which can be positionally kept by anchors, respectively, and can be moved in a free direction. The sea bottom excavation facility has functions of a high-pressure water nozzle, an actuation cylinder, a two-directional mobile cylinder, a light oil separation sheet for flotation and the like. At a soft stratum with a sedimentary layer in the sea bottom, high-pressure water is injected into the stratum and soil sealing is released to recover methane hydrate by separation caused by density difference. At a hard stratum, a bit is attached to a tip of the high-pressure water nozzle and a rock mass is crushed to extract the hydrate.</p> |
