Fracking With CO2, Not Water, Could Be More Efficient, Study Says
Agence France-Presse
May 30, 2019 4:11 PM (source)
Fracking With CO2, Not Water, Could Be More Efficient, Study Says
研究指出 :以二氧化碳進行壓裂可能比水更有效
May 30, 2019 4:11 PM
Carbon dioxide appears to be more efficient than water for hydraulic fracturing, or fracking, to extract oil and natural gas, according to a study led by scientists in China published Thursday.
Fracking is a process by which high-pressure fluids are injected into underground rock to create cracks to release oil and gas.
In the United States, fracking has fueled an oil boom since the early 2000s.
Currently, the most widespread method involves using large quantities of water mixed with chemicals.
But the method is controversial because the fluids are suspected of contaminating the aquifer — the underground layer of permeable rock that bears water — and of triggering mini-earthquakes.
The use of carbon dioxide instead of water to reduce the environmental impact of fracking has been the subject of studies for years.
Scientists from the Chinese Academy of Sciences and China University of Petroleum in Beijing tested the method in a lab and in five wells at the Jilin oil field in northeastern China.
"To our delight, oil production increased by [around] four- to 20-fold after the entire CO2 fracturing process," compared with the use of a water-chemical mix, wrote the authors of the study published in the American journal Joule.
The experts said carbon dioxide is better at breaking up the shale.
'Greener alternative'
"These real-world results revealed that as compared to water fracturing, CO2 fracturing is an important and greener alternative, particularly for reservoirs with water-sensitive formations, located at arid areas, or other conditions that making water fracturing less applicable," the authors added.
This would hold especially true in arid regions, where water currently needs to be transported by tanker trucks.
The scientists argue that this technique would allow CO2 — the main greenhouse gas emitted by human activity blamed for global warming — to be trapped in the ground, thereby removing it from the atmosphere.
However, injecting CO2 to extract hydrocarbons whose combustion would lead to more carbon emissions can seem counterproductive.
"CO2 fracking might ultimately have environmental benefits compared to fracking with water, but this study does not include the analysis that is needed to establish whether CO2 fracking is likely to lead to an overall reduction in global greenhouse gas emissions," said Hannah Chalmers, a senior lecturer at the University of Edinburgh.
根據一項由中國科學家主持並在週四(編按:2019 年 5 月 30 日)發表的研究,二氧化碳(carbon dioxide)似乎比水更適合(efficient)用在抽取(extract)石油與天然氣的水力壓裂(hydraulic fracturing) ,此項技術也稱為液壓破裂(fracking)。
壓裂是將高壓液體(fluid)注入(inject)地底岩層中,製造出縫隙(crack)以釋出石油與天然氣的過程。
自 2000 年代初期以來,壓裂便已促成(fuel)了美國石油開採的榮景(boom)。
目前最廣為使用的開採方式是將大量經過化學處理的用水注入地下。
不過這項技術卻因可能汙染含水層(aquifer)並引發(trigger)小型地震而備受爭議。含水層即位於地底,可滲透(permeable)並保水的岩層。
長久以來,用二氧化碳取代水以降低壓裂造成環境衝擊的作法一直是該領域的研究重點。
中國科學院(Chinese Academy of Sciences)與北京的中國石油大學(China University of Petroleum)科學家在實驗室及中國東北吉林(Jilin)油田的 5 座油井中測試了這項新技術。
「值得高興的是,相較於使用水與化學物質的混合物,使用二氧化碳壓裂讓石油產量增加約4到20倍(fold)。」進行這項研究的人員寫道。研究報告亦發表在美國期刊《焦耳》(Joule)。
專家說二氧化碳較能分離(break up)頁岩(shale)。
「更環保的作法」
「現實反映出來的結果是,比起以水壓裂,二氧化碳是個重要且較環保的(green)替代選項,尤其對位在乾燥(arid)缺水區結構(formation)易受破壞的儲水層(reservoir),或其他較不適合(applicable)使用水壓裂的情況下更是如此。」研究人員補充道。
這在乾燥地區尤其明顯,這些地區的用水目前需要透過油罐卡車運送。
科學家表示,這項技術會將二氧化碳鎖(trap)在地底,從而減少其在大氣層中的含量。二氧化碳也就是藉由人類活動排放(emit)出來而造成全球暖化的主要溫室氣體(greenhouse gas)。
然而,以二氧化碳以抽取碳氫化合物(hydrocarbons)的方式,在碳氫化合物的燃燒(combustion)過程可能導致碳的排放(emission)量增加,最後適得其反(counterproductive)。
「相較於水壓裂法,二氧化碳壓裂法或許對環境較為有益,但這項研究並沒有包含對二氧化碳壓裂法是否會降低全球溫室氣體排放的分析。」英國愛丁堡大學(University of Edinburgh)資深講師漢娜‧查默斯(Hannah Chalmers)表示。
Language Notes
hydraulic [haɪˋdrɔlɪk] (a) 水力的,液力的;水力學的;水壓的,液壓的
* 注意本字重音在第 2 音節
fracture [ˋfræktʃɚ] (v) 使破裂;使斷裂
* 本字也可作名詞,意即「(硬物的)斷裂;骨折」
fracking [ˋfrækɪŋ] (n) 液體壓裂法,液壓破碎法
extract [ɪkˋstrækt] / [ɛkˋstrækt] (v) 抽出;採掘;提取
* 注意本字重音在第 2 音節;亦可作名詞,重音則在第 1 音節([ˋekstrækt] / [ˋɛkstrækt]),意思是「(尤指食物或藥物的)提出物,精華,汁」
inject [ɪnˋdʒekt] / [ɪnˋdʒɛkt] (v) 注射;引入;投入
* 注意本字重音在第 2 音節
fuel [ˋfjuəl] / [ fjʊəl] (v) 對 . . . . . . 供給燃料;給 . . . . . . 加油;激起;刺激
* 本字也可作名詞,指「燃料;燃燒劑」或「刺激因素」
aquifer [ˋækwəfɚ] / [ˋɑkwəfɚ] (n) 含水土層,地下蓄水層
permeable [ˋpɝmiəbl̩] / [ pɝmɪəbl̩] (a) 有滲透性的;可穿過的
* permeate [ˋpɝmi͵eɪt] / [ˋpɝmɪ͵et] (v) 滲透;瀰漫;遍佈;充滿
shale [ʃeɪl] / [ʃel] (n) 頁岩;泥板岩
reservoir [ˋrezɚ͵vwɑr] / [ rezɚ͵vɔr] / [ rɛzɚ͵vɔr] (n) 水庫;貯水池
arid [ˋærɪd] (a) 乾旱的;乾燥的
hydrocarbon [͵haɪdrəˋkɑrbən] (n) 碳氫化合物
* 本字由字首 “hydro-”「水的;氫的」與名詞 “carbon”「碳」組成;注意重音在第 3 音節
combustion [kəmˋbʌstʃən] (n) 燃燒,氧化
* 注意本字重音在第 2 音節
* combust [kəmˋbʌst] (v) 燒掉;開始燃燒
emission [iˋmɪʃən] / [ɪˋmɪʃən] (n)(氣體、熱量、光線等的)排放,散發,射出
* 注意本字重音在第 2 音節
* emit [iˋmɪt] / [ɪˋmɪt] (v) 發出,射出,散發(光、雜訊、氣味或氣體)
Check your vocabulary!
Fill in the blanks with a word or phrase from the list above. Make necessary changes. After you finish, highlight the blanks to reveal the hidden answers.
1. The desert is so arid that nothing can grow there.
2. They used to extract iron ore from this site.
3. Certain types of sandstone are permeable to water.
4. Rising expectations about the standards of health can therefore be seen as fueling further demand for health care.
5. Environmental groups want a substantial reduction in the emission of greenhouse gases.
編譯:外語教學暨資源中心 編輯小組
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