采礦專業(yè)畢業(yè)設(shè)計外文翻譯--關(guān)于煤層沼氣的一些經(jīng)常出現(xiàn)的問題

1、<p><b>　　附錄1</b></p><p>　　關(guān)于煤層沼氣的一些經(jīng)常出現(xiàn)的問題</p><p><b>　　什么是煤層沼氣？</b></p><p>　　天然氣的成分是一種叫做甲烷（CH4）的物質(zhì)。煤層沼氣是一種類似于甲烷的化合物，它在天然氣中是一種原生能源。煤層沼氣，顧名思義，是在煤層中發(fā)現(xiàn)的，它的生

2、產(chǎn)工藝與傳統(tǒng)的生產(chǎn)方法不同，然而它與傳統(tǒng)天然氣的使用及銷售情況卻是相似的。煤層沼氣是通過兩種方法產(chǎn)生的，一種是由于微生物活動的生物作用，一種是隨著煤的深度其熱量增加的熱力作用。由于水的壓力，煤層中經(jīng)常含有大量水和沼氣。</p><p>　　現(xiàn)在，美國從煤層中獲得的天然氣大約占總的天然氣產(chǎn)出的7%，羅克山區(qū)估計184兆立方英尺的天然氣中近三分之一是從席層中獲得的。據(jù)統(tǒng)計約24兆立方英尺的煤層沼氣可能蘊藏在曼塔那和懷

3、俄明的帕得河水域。</p><p>　　煤層沼氣存在于哪里？</p><p>　　根據(jù)美國阿拉巴馬州煤層沼氣聯(lián)合會的資料，美國13%的地下有煤，一些煤層中蘊含不甲烷，與我們所知的天然氣或煤層沼氣相似。</p><p>　　根據(jù)美國地質(zhì)勘測聯(lián)合會資料，羅克山區(qū)有大量煤存在，并且有資料顯示這些煤層中儲藏有沼氣。未開發(fā)的煤層沼氣資源存在于懷俄明和曼塔那的帕得河水域，懷俄明

4、的大格林河水域，科羅拉多和新墨西哥的三圈水域。估計羅克山區(qū)有大約30—58兆立方英尺的可利用煤層沼氣。</p><p>　　怎樣從煤層中提取沼氣？</p><p>　　在蘊含有甲烷的煤層中有一個抽水裝置相聯(lián)結(jié)，甲烷就通過一個鉆井機連同地下水被一同抽出。因為甲烷不易溶于水，所以在水進入抽水機前甲烷就與水完全分離開來。在煤層的蓄水層中，提取煤層沼氣的同時提取出水可以控制煤層氣體的水壓減小。煤層

5、沼氣的生產(chǎn)中應(yīng)盡量使煤層不要脫水。目的是減小煤層中的水壓，使其恰好在煤層頂端。然而，在時水位會降低到煤層中。水在煤層到井筒移動的過程中使氣體移向井中。水壓釋放的同時，氣體上升，并且與水分離從管道中輸送走。</p><p>　　從帕得河水域中預(yù)計可以抽出多少甲烷氣體？</p><p>　　對帕得河水域的甲烷氣體數(shù)量的預(yù)計會不斷變化，估算結(jié)果出會經(jīng)常被重新設(shè)計。有很多的方法去預(yù)計煤層中可利用的

6、氣體量；所有的方法都有準(zhǔn)確和不準(zhǔn)確的變化程度。</p><p>　　根據(jù)美國地質(zhì)勘測公司的煤據(jù)得到：帕得河水域可重新利用的煤層沼氣變化范圍為8.24兆立方英尺。懷俄明石油氣體保護委員會估算，懷俄明地區(qū)帕得河水域可重新利用的煤層沼氣做出估算，結(jié)果大約為0.8至1.0兆立方英尺。環(huán)境影響力聲明報告帕得河水域煤層沼氣可重新利用氣體預(yù)計為2.5兆立方英尺。</p><p>　　怎樣估算一個地區(qū)地下

7、煤層中的甲烷氣體量？</p><p>　　有兩面三刀種常用的方法來估算煤層中可利用的甲烷氣體量。一種方法需要估算鉆探到煤層頂部的甲烷貯藏量，然后從煤層中提取中心。從煤心中重新獲得的甲烷量，可用來算煤中每單位體積氣體的容量。如果很多煤心被鉆探，并且甲烷氣體釋放量被查明，我們就可估算出一個地區(qū)可利用氣體的量了。這種方法的局限性為：（1）在氣體釋放之前取得煤心有許多干擾因素應(yīng)被考慮；（2）這種方法太貴；（3）不是每個地

8、區(qū)有開發(fā)前途的煤層沼氣都可被勘測到。</p><p>　　另外一種預(yù)測一個地區(qū)地下煤層中的甲烷量的方法為根據(jù)我們所知道的一些信息，關(guān)于這個地區(qū)煤層賦存情況和煤層沼氣開發(fā)的可行性，基于這些信息我們進行一系列的推算。</p><p>　　對于處理煤層沼氣采出水的現(xiàn)有管理準(zhǔn)則是什么？</p><p>　　現(xiàn)在，在帕得河水域開采煤層沼氣采出的水是通過以下幾種方法處理的： &

9、lt;/p><p>　　（1）排放進河道，雖然直接排放到河流存在新的操作法，但是經(jīng)過調(diào)整，還是可以直接排入河流中的。一些先進的提案充許有控制的固定流量的排放水到河流中。</p><p>　?。?）筑堤蓄水，這種方法涉及到建造一個池塘，用來貯存開采煤層沼氣采出的水或者充許它滲入地面下。對于這個蓄水池有許多條件：“水池”、“池里的水不外溢”或“水池滲透”，雖然它們不會直接向地表排水，但是蓄水池并不

10、是這些水的終點站，它們會被排放到地面下，一些蓄水池中滲透量的百分比十分接近一些河流的滲入地下的速率。</p><p>　?。?）應(yīng)用于農(nóng)作物或牧場，一些水可通過灌溉設(shè)備澆灌農(nóng)田。</p><p>　　（4）另外一些用途：開采煤層沼氣采出的水，也可用來控制粉塵，在一些情況下可用于煤礦生產(chǎn)。</p><p>　　在東懷俄明和曼塔那的另外上些利用煤層沼氣水的方法是再把這些

11、水重新注入到蓄水層，這個方法在西南美州實踐過，里的煤層沼氣被用來注射到深層煤層沼氣裸露的煤層結(jié)構(gòu)中，這個方法可防止地表排放。還有另外一些建議存在，例如這個方法的可行性——經(jīng)濟、物質(zhì)和環(huán)境，向被抽干的煤層重新注入煤層沼氣水或者把它注入到經(jīng)調(diào)查煤層沼氣裸露煤層的上部或下部的蓄水層。</p><p>　　為什么人們這樣擔(dān)憂開采煤層沼氣采出水的處理？</p><p>　　有一些關(guān)于煤層沼氣開發(fā)的擔(dān)

12、憂還有怎樣去解決提取早烷所抽出的水。</p><p>　　開采煤層沼氣產(chǎn)出水量：</p><p>　　提取煤層沼氣涉及到從充滿水的煤層中抽出大量的水目的是釋放被水壓控制在煤層中的氣體。</p><p>　　對于這么多煤層沼氣水的處理成為許多爭論的源頭。第個鉆井預(yù)計每分鐘采出5—20加侖的水。如果按一分鐘12加侖來計算，那么一天從一個鉆井中產(chǎn)出的總水量大約為17280

13、加侖。一般80英畝土地就有一個鉆井。在帕得河水域，有三個承載甲烷的煤層；因此，在那里每80英畝可能有三個鉆井。</p><p>　　開采煤層沼氣水產(chǎn)出的水的特性及它對土壤的影響？</p><p>　　煤層沼氣采出水有高鹽分的危險，經(jīng)常有高鈉的危險，盡量使煤層沼氣水中的鈉含量適于灌溉，對于農(nóng)作物有灌溉則要更小心。隨著時間的推移，煤層沼氣水中的鹽份在土壤深部積累致使鹽的含量對農(nóng)作物產(chǎn)生影響。這

14、種含有鹽分多的土壤條件會阻礙農(nóng)作物的生長，因為植物從這種土壤中獲取水份是很難的。</p><p>　　煤層沼氣水中鈉的危害對一些土地資源形成附加的威害。含鈉的灌溉水會導(dǎo)致土壤硬化并且損害土壤的滲透系數(shù)，影響水的可用性和通氣，這對農(nóng)作物生長和產(chǎn)量影響都較大。在有膨脹黏土的濕潤土壤中，鈉導(dǎo)致粘土的濕潤程度增加，導(dǎo)致粘土微粒的分散和移動。在曼塔那美洲目前的調(diào)查顯示，該地區(qū)特有的煤層沼饣水中含鈉量可以降低，粘土土壤的物理

15、和化學(xué)性質(zhì)，導(dǎo)致土壤完全不適合農(nóng)作物生長。</p><p>　　除了土壤結(jié)構(gòu)外，還有很多因素能夠影響土壤滲透率。礦物、石灰，倍半氧化物、有機物的充裕、耕種、灌溉方法、滲透率。首先，充分的水和時間在耕種的整個過程中對土壤的滲透起一個推動作用。唯一確定含鈉鹽灌溉水對土壤的影響是周期性的測驗灌溉的水和土壤。</p><p>　　煤層沼氣的特性及它對農(nóng)作物的影響？</p><p

16、>　　控制大量的煤層沼氣采出的水流入河道，在這種情況下對人類健康和現(xiàn)有的河岸及沼澤地造成危脅。高鹽和高鈉的水可以改變河岸和沼澤地植物群落，不耐鹽的種類被更多耐鹽的種類所取代。鹽雪松、俄羅斯橄檻等有害物種的侵入被含鹽條件所提高，這個事實被很好的證明。</p><p>　　煤層沼氣的開發(fā)會不減少向河流、泉和井的排放？</p><p>　　由于從煤層蓄水層中抽出大量的水，從而就產(chǎn)生了對于泉

17、水和河流、飲用水的水位、牲畜飲用的井水的影響的關(guān)注。如果煤層蓄水層為泉水和河流提供水份（煤層向河流或泉排水），一個地區(qū)的煤層沼氣開發(fā)可能減少向那些水體排水。如果河流和泉不靠煤層蓄水層的排水，流量減少就會很小。然而，如果煤層沼氣水是陸地供給或流向池塘（那些池塘大部分經(jīng)常不被充填，并且排放到地面下），在開發(fā)過程中由于地下水流向河流，河流流量會增加。</p><p>　　如果飲用水或牲畜用井直接從煤層中得到，那么一個地

18、區(qū)的煤層沼氣開發(fā)就可能減少井的水位。對于泉水流量的影響期間和井中可利用水，就會依靠總地區(qū)的開發(fā)和調(diào)整。</p><p><b>　　附錄2</b></p><p>　　Coal bed Methane - Frequently Asked Questions</p><p>　　Kristin Keith, Jim Bauder, Monta

19、na State University</p><p>　　John Wheaton, Montana Bureau of Mines and Geology</p><p>　　What is coal bed methane? </p><p>　　A component of natural gas is a substance called methane

20、(CH4). Coal bed methane (CBM) is the same compound as the methane which is the primary energy source in natural gas. Coal bed methane, however, is found in coal seams, and produced by non-traditional means, and therefo

21、re while it is sold and used the same as traditional natural gas, its production is very different. Coal bed methane is generated either from a biological process as a result of microbial action or from a thermal proces

22、s a</p><p>　　Currently, natural gas from coal beds is approximately 7% of the total natural gas production in the United States, nearly one-third of the estimated 184 trillion cubic feet of gas in the Rocky

23、Mountain Region is in coal seams. An estimated 24 TCF of recoverable CBM resources </p><p>　　may lie below the Powder River basin of Montana and Wyoming. </p><p>　　Where does coal bed methane e

24、xist? </p><p>　　According to the CBM Association of Alabama, 13% of the land in the lower 48 United States has some coal under it, and some of this coal contains methane - either in the form we know as t

25、raditional natural gas or as CBM. </p><p>　　According to the United States Geological Survey, the Rocky Mountain Region has extensive coal deposits with significant storage of coal-bed methane gas. Untapp

26、ed resources of coal bed methane exist in the Powder River Basin of Wyoming and Montana, the Greater Green River Basin of Wyoming, Colorado, and Utah, the Uinta-Piceance Basin of Colorado and Utah, and the Raton and San

27、Juan Basins of Colorado and New Mexico. It is estimated the Rocky Mountain region has about 30-58 trillion cubic feet </p><p>　　How do gas companies extract the methane from the coal seam? </p><p

28、>　　Methane travels with the ground water being pumped from the coal from a well drilled and completed in a coal seam that contains methane and fixed with a water pump.Since methane has very low solubility in water it

29、separates from the water in the well before the water enters the pump. The extraction of CBM involves pumping the available water from the coal seam aquifer in order to reduce the water pressure that holds the gas in the

30、 coal seam. CBM producers try not to dewater the coal seam. The g</p><p>　　level drops into the coal seam. Water moving from the coal seam to the well bore encourages gas migration toward the well. As this

31、 water pressure is released, the gas will rise and is separated from the water and be piped away. </p><p>　　How much methane gas do they estimate will be extracted from the Powder River Basin? </p>&l

32、t;p>　　Estimates on the amount of methane gas in the Powder River Basin vary and the estimates are often re-calculated. There are several methods to estimate the amount of recoverable gas from a coal seam; all have var

33、ying degrees of accuracy and inaccuracy. </p><p>　　According to the U. S. Geological Survey the amount of recoverable CBM from the Powder River Basin ranges from 8.24 ¨C 22.42 trillion cubic feet of ga

34、s. The Wyoming Oil and Gas Conservation Commission estimates 31.8 trillion cubic feet of recoverable CBM in the Powder River Basin of Wyoming alone. The Montana Bureau of Mines and Geology and the U.S. Department of En

35、ergy have separately estimated between 0.8 ¨C 1.0 trillion cubic feet of recoverable CBM in the Powder River Basin ofMontana. The </p><p>　　How do they estimate the amount of methane gas which will come

36、 from a region underlain by coal? </p><p>　　There are two popular methods for estimating recoverable methane gas from a coal seam.One method requires estimating methane reserves by boring to the top of the c

37、oal seam, then extracting a core from the coal. The amount of methane recovered from the coal core is used to estimate gas content per unit volume of coal. If a number of cores are drilled and methane gas release is ob

38、served, one can estimate the amount of gas available in a region. The limitations to this method are: 1) there is mu</p><p>　　Another method of estimating the amount of methane in a region underlain by coal

39、 is through a series of calculations based on information we already know about the coal in the region and the feasibility of CBM development. </p><p>　　What are the current management practices for disposal

40、 of the CBM product water? </p><p>　　Currently, CBM product water in the Powder River Basin is managed by the following methods: </p><p>　　Discharged into a stream channel - Although direct stre

41、am discharge is no longer permitted on new wells, existing operations were !°grandathered!± and are still discharging directly into streams. Also, proposals are being advanced to allow regulated discharges dur

42、ing certain flow conditions. </p><p>　　Impounded ¨C This ethod involves constructing a pond in which CBM product water is stored or allowed to infiltrate to the subsurface. There are several terms fo

43、r these impoundments:” holding ponds”, “zero discharge ponds” or “infiltra ponds”. Although they do not directly discharge water on the land surface, most impoundments are not lined and do discharge to the subsurface. S

44、ome percentage of seepage flow from impoundments is likely to reach some stream channels via subsurface flow. </p><p>　　Land applied to crop or rangeland ¨through soe form of irrigation equipment some

45、water is used for irrigation. </p><p>　　Other uses - CBM product water is also used for dust control, and in some cases is being used by coal mines. </p><p>　　Another option being proposed for

46、 disposal of CBM product water in eastern Wyoming and Montana is to reinject the CBM product water back into an aquifer(s). This practice is happening in the southwest U.S. where CBM product water is injected into deepe

47、r formations below CBM-bearing coal. This approach avoids surface discharge. Many opinions exist, and the feasibility - economic, physical, and environmental - of either reinjecting CBM product water to the coal seam fro

48、m which it was pumped or in</p><p>　　Why are people concerned about CBM product water? </p><p>　　There are several concerns about coal bed methane development and how to manage the water which i

49、s pumped to extract the methane. </p><p>　　The quantity of the CBM product water: </p><p>　　The extraction of CBM involves pumping large volumes of water from the saturated coal seam in order to

50、 release the water pressure holding the gas in the coal seam. What to do with this volume of often marginal-quality CBM product water is a source of much debate. Each well is expected to produce 5 to 20 gallons of wa

51、ter per minute. At 12 gallons per minute, a total of 17,280 gallons of water per day may come from one well. It is common to have to have one well every 80 acres. In the Powd</p><p>　　The quality of CBM

52、product water and its effect on soil: </p><p>　　Coal bed methane product water has a moderately high salinity hazard and often a very high sodium hazard based on standards used for irrigation suitability. I

53、rrigation with water of CBM product water quality on range or crop lands should be done with great care and managed closely. With time, salts from the product water can accumulate in the root zone to concentrations whic

54、h will affect plant growth. Saline conditions stunt plant growth because plants must work harder to extract water from th</p><p>　　The sodium hazard of CBM product water poses additional threats to certain

55、soil resources. Sodic irrigation water causes soil crusting and impairs soil hydraulic conductivity - affecting water availability and aeration, important to crop growth and yield. Upon wetting soils with swelling clay

56、, sodium causes the degree of swelling in the clay to increase, causing dispersion and migration of clay particles. Current research at Montana State University shows water with sodium levels equal to tha</p><

57、;p>　　The risk of sodium has been observed in other soil textures. Jim Oster (personal com.) observed crusting, poor soil tilth, hardsetting and aggregate failure on a sandy loam soil irrigated with water EC ~ 1, SAR

58、~ 7. Minhaus (1994) saw irreversible and severe reduction in infiltration on sandy loam soil with long term irrigation under high SAR water followed by </p><p>　　monsoon rain. </p><p>　　There a

59、re many factors in addition to soil textures that affect infiltration rates. Mineralogy, lime, sesquiozides, organic matter content, cultivation, irrigation method, wetting rate, antecedent water content and time since

60、cultivation all play a roll in infiltration of soils. The only way to be certain of the impacts of saline/sodic irrigation water on the soil is to periodically sample and test the irrigation water and the soil. </p&g

61、t;<p>　　The quality of CBM product water and its effect on plants: </p><p>　　Disposal of the large quantity of CBM product water into stream channels and on the landscape poses a risk to the health an

62、d condition of existing riparian and wetland areas. The high salinity and sodium levels in the product water may alter riparian and wetland plant communities with the replacement of salt intolerant species with more sal

63、t tolerant species. It is well recognized that encroachment of such noxious species as salt cedar, Russian olive, leafy spurge is enhanced by saline conditio</p><p>　　Will CBM development reduce flow to stre

64、ams, springs and wells? </p><p>　　As a result of the large amount of water being pumped from the coal seam aquifers, there is concern of impact to springs and streams and to the level of water in drinking, a

65、nd livestock wells. The answer to this question is very location specific. If the spring or stream is fed by the coal seam aquifer (the coal seam surfaces and discharges water into a stream or spring), CBM development

66、in the local area may well decrease the flow to those water bodies. If the spring or stream is not fed by </p><p>　　If the drinking water or livestock well gets water directly from the coal seam, then CBM d