海域メタンハイドレートガス開発の経済性及びCO_2排出量評価 [in Japanese] Evaluation of Economics and CO_2 Emission for Developing Offshore Methane Hydrate Deposit [in Japanese]
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For offshore methane hydrate deposit, we constructed a conceptual production system model incorporated with the software named QUE$TOR, and a model for direct and indirect CO_2 emission assessment by reference to the induced CO_2 emission data from the 1995 inter-industry relations table for environment analysis. Based on the calculated data, we evaluated economics and CO_2 emission in the gas production from a hypothetical offshore hydrate deposit. The three production methods were evaluated! Depressurization using vertical wells; depressurization using horizontal wells! and hot-water injection using horizontal wells. The gas production cost was evaluated to be 818 and 53 Yen/Sm^3 for the depressurization method using vertical and horizontal wells respectively, and 67 Yen/Sm^3 for the hot-water injection method. In regard to CO_2 emission, the depressurization method yielded 66.51 g-C/Mcal for the vertical-well case and 58.43 g-C/Mcal for the horizontal-well case. These values were lower than the reported value for LNG (69.77 g-C/Mcal). The case of hot-water injection emitted more CO_2 at 79.59 g-C/Mcal, but it was lower than the value for oil (83.63 g-C/Meal). This study demonstrated that the depressurization using horizontal wells was most promising method from economical and environmental concerns, but its production cost is much higher than the domestic natural-gas supply price. For utilizing offshore methane hydrates as an economically feasible .resource, the research and development are required in the following area: (1) Completing well with a horizontal section exceeding 1,000 m at a shallow depth under deep water; and (2) Cost reduction in offshore well completion and production system. Moreover, gas productivity from offshore methane hydrates must be evaluated more rigorously from field production tests and simulation studies.
- Journal of the Japan Institute of Energy
Journal of the Japan Institute of Energy 82(4), 197-207, 2003-04-20
The Japan Institute of Energy