報告書番号

U91057

タイトル（和文）

ＣＡＥＳ－Ｇ／Ｔ発電のための硬岩地下空洞の圧縮空気貯蔵機能評価－ボーリング孔内水封試験のための金剛サイトの地質－

タイトル（英文）

AIR TIGHTNESS OF HARD ROCK FOR COMPRESSED-AIR ENERGY STORAGE -GEOLOGY OF KONGO TEST YARD FOR BOREHOLE WATER SEALINGTEST-

概要 （図表や脚注は「報告書全文」に掲載しております）

電力貯蔵技術として有望な圧縮空気貯蔵ガスタービン（ＣＡＥＳ－Ｇ／Ｔ）発電の硬岩における水封式空気貯蔵方式は，岩盤空洞内に貯蔵した高圧空気の漏洩を地下水の圧力により防止する方法であり，実現には数１０気圧での貯蔵可能性を確認する必要がある。このため実施したボーリング孔内での水封試験によると，４００ｍの深さまで，ほぼ間隙水圧かそれ以上の高圧空気の貯蔵が可能であり，岩盤の水封機能には間隙水圧分布が最も支配的である。この間隙水圧分布に影響すると考えられる地下深部までの地質，透水係数分布の調査結果によると，試験サイトには，灰白色と桃色の花崗閃緑岩が分布し，ボーリングコアの節理密度は各々１０本／ｍ，１５～２０本／ｍ程度であり，桃色花崗閃緑岩で節理が多い。深度方向の節理分布特性と透水係数分布には関連性があり，透水係数の大きい箇所で，コアの節理密度，ボアホールテレビジョンによる開口節理密度が大きいとい

概要 （英文）

COMPRESSED-AIR ENERGY STORAGE AND GAS-TURBINE (CAES-G/T) GENERATION COULD BE A NEW LOAD-LEVELING POWER SUPPLY. TO DEVELOP AN ECONOMICAL SYSTEM THAT PREVENTS LEAKAGE OF AIR STORED (MORE THAN 20 ATM.) BY UNDERGROUND WATER PRESSURE SURROUNDING AN UNLINED CAVERN IN HARD ROCK,IT IS NECESSARY TO CONFIRM THE AIR TIGHTNESS. FOR THIS PURPOSE,A WATER SEALING TEST WAS PERFORMED IN A DEEP DRILLED HOLE. BEFORE THE TEST,THE GEOLOGY AND UNDERGROUND WATER CHARACTERISTICS OF THE KONGO TEST YARD,WHICH IS UNDERLAIN BY GRANITIC ROCKS WERE EXAMINED,THE RESULTS ARE SHOWN BELOW. (1) THE AIR TIGHTNESS PRESSURE MEASURED BY THE WATER SEALING TEST WAS ALMOST EQUAL TO OR GREATER THAN THE PORE-WATER PRESSURE AT EACH DEPTH. (2) THE GEOLOGY AND PERMEABILITY OF THE TEST YARD,WHICH WILL PROBABLY AFFECT THE DISTRIBUTION OF THE PORE-WATER PRESSURES,ARE DESCRIBED BELOW. 1. THE TEST YARD IS UNDERLAIN BY GRANODIORITE COMPOSED OF GRAYISH WHITE AND PINK PARTS. THERE ARE MANY JOINTS AND MICROCRACKS IN THE PINK PARTS. THESE ARE ACCOMPANIED BY WHITE AND PINK VEINS GENERATED BY HYDROTHERMAL REACTION. 2. IT SEEMS THAT THE DISTRIBUTION OF ROCK FRACTURES IN THE DRILLED HOLE IS SIMILAR TO THAT OF THE COEFFICIENT OF PERMEABILITY WHICH WAS 10**-7 TO 10**-4 CM/S. IT IS LIKELY THAT THERE ARE MANY JOINTS AND OPEN JOINTS WHERE THE COEFFICIENTS OF PERMEABILITY ARE LARGE. (3) THESE RESULTS SHOW THE IMPORTANCE OF EXAMNING THE DISTRIBUTION OF THE PORE-WATER PRESSURES IN GEOLOGICAL INVESTIGATIONS FOR CAES.

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