首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Directions: Read the passage. Then answer the questions. Give yourself 20 minutes to complete this practice set.
Directions: Read the passage. Then answer the questions. Give yourself 20 minutes to complete this practice set.
admin
2014-09-29
19
问题
Directions: Read the passage. Then answer the questions. Give yourself 20 minutes to complete this practice set.
PETROLEUM RESOURCES
Petroleum, consisting of crude oil and natural gas, seems to originate from organic matter in marine sediment. Microscopic organisms settle to the seafloor and accumulate in marine mud. The organic matter may partially decompose, using up the dissolved oxygen in the sediment. As soon as the oxygen is gone, decay stops and the remaining organic matter is preserved.
Continued sedimentation—the process of deposits’ settling on the sea bottom— buries the organic matter and subjects it to higher temperatures and pressures, which convert the organic matter to oil and gas. As muddy sediments are pressed together, the gas and small droplets of oil may be squeezed out of the mud and may move into sandy layers nearby. Over long periods of time(millions of years), accumulations of gas and oil can collect in the sandy layers. Both oil and gas are less dense than water, so they generally tend to rise upward through water-saturated rock and sediment.
Oil pools are valuable underground accumulations of oil, and oil fields are regions underlain by one or more oil pools. When an oil pool or field has been discovered, wells are drilled into the ground. Permanent towers, called derricks, used to be built to handle the long sections of drilling pipe. Now portable drilling machines are set up and are then dismantled and removed. When the well reaches a pool, oil usually rises up the well because of its density difference with water beneath it or because of the pressure of expanding gas trapped above it. Although this rise of oil is almost always carefully controlled today, spouts of oil, or gushers, were common in the past. Gas pressure gradually dies out, and oil is pumped from the well. Water or steam may be pumped down adjacent wells to help push the oil out. At a refinery, the crude oil from underground is separated into natural gas, gasoline, kerosene, and various oils. Petrochemicals such as dyes, fertilizer, and plastic are also manufactured from the petroleum.
As oil becomes increasingly difficult to find, the search for it is extended into more-hostile environments. The development of the oil field on the North Slope of Alaska and the construction of the Alaska pipeline are examples of the great expense and difficulty involved in new oil discoveries. Offshore drilling platforms extend the search for oil to the ocean’s continental shelves—those gently sloping submarine regions at the edges of the continents. More than one-quarter of the world’s oil and almost one-fifth of the world’s natural gas come from offshore, even though offshore drilling is six to seven times more expensive than drilling on land. A significant part of this oil and gas comes from under the North Sea between Great Britain and Norway.
Of course, there is far more oil underground than can be recovered. It may be in a pool too small or too far from a potential market to justify the expense of drilling. Some oil lies under regions where drilling is forbidden, such as national parks or other public lands. Even given the best extraction techniques, only about 30 to 40 percent of the oil in a given pool can be brought to the surface. The rest is far too difficult to extract and has to remain underground.
Moreover, getting petroleum out of the ground and from under the sea and to the consumer can create environmental problems anywhere along the line. Pipelines carrying oil can be broken by faults or landslides, causing serious oil spills. Spillage from huge oil-carrying cargo ships, called tankers, involved in collisions or accidental groundings can create oil slicks at sea. Offshore platforms may also lose oil, creating oil slicks that drift ashore and foul the beaches, harming the environment. Sometimes, the ground at an oil field may subside as oil is removed. The Wilmington field near Long Beach, California, has subsided nine meters in 50 years; protective barriers have had to be built to prevent seawater from flooding the area. Finally, the refining and burning of petroleum and its products can cause air pollution. Advancing technology and strict laws, however, are helping control some of these adverse environmental effects.
Directions: Now answer the questions.
Petroleum, consisting of crude oil and natural gas, seems to originate from organic matter in marine sediment. Microscopic organisms settle to the seafloor and
accumulate
in marine mud. The organic matter may partially decompose, using up the dissolved oxygen in the sediment. As soon as the oxygen is gone, decay stops and the remaining organic matter is preserved.
Continued sedimentation—the process of deposits’ settling on the sea bottom— buries the organic matter and subjects it to higher temperatures and pressures, which convert the organic matter to oil and gas.
As muddy sediments are pressed together, the gas and small droplets of oil may be squeezed out of the mud and may move into sandy layers nearby. Over long periods of time(millions of years), accumulations of gas and oil can collect in the sandy layers. Both oil and gas are less dense than water, so they generally tend to rise upward through water-saturated rock and sediment.
According to paragraph 1, which of the following is true about petroleum formation?
选项
A、Microscopic organisms that live in mud produce crude oil and natural gas.
B、Large amounts of oxygen are needed for petroleum formation to begin.
C、Petroleum is produced when organic material in sediments combines with decaying marine organisms.
D、Petroleum formation appears to begin in marine sediments where organic matter is present.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/mTfO777K
0
托福(TOEFL)
相关试题推荐
Completethenotesbelowusingwordsfromthebox.ArtGalleryCathedralCastleGardensMarketsTouristattractionsopenallday
Completetheformbelow.WriteNOMORETHANTHREEWORDSAND/ORNUMBERSforeachanswer.AccommodationReques
Completethesentencesbelow.WriteNOMORETHANTWOWORDSforeachanswer.JobsatisfactionstudyResearcherswereunableto__
Choosethecorrectletter,A,BorC.ResearchprojectonattitudestowardsstudyTonyisparticularlyimpressedbyPhoebe’sab
Completethenotesbelow.WriteNOMORETHANTWOWORDSAND/ORANUMBERforeachanswerENVIRONMENTALCHANGEDISCUSSIONInSouthe
Completethenotesbelow.WriteNOMORETHANTWOWORDSAND/ORANUMBERforeachanswerENVIRONMENTALCHANGEDISCUSSIONInSouthe
Choosethecorrectanswer,A,BorC.WhatchangecausedchangesincrocodilepopulationsinNorthAfrica?
WhatdoesChloedecideaboutthefollowingsubjects?Writethecorrectletter,A,BorC,nexttoquestions26-30.AShewills
Completethenotesbelow.WriteNOMORETHANTWOWORDSforeachanswer.ROBERTSCOMPANYFoundingThemostimportantprincipalof
随机试题
Mr.Harrisdecidedtoopenanewstoreand______manyclerks.
要素饮食的适应证是【】
涂片的制备时,下列说法不正确的是
与CT图像显示上下位置偏移有关的操作是
医师应怎样全面看待健康与疾病
有权就实施行政许可收取费用作出规定的规范性文件是()。
某计算机采用16位定长指令字格式,其CPU中有一个标志寄存器,其中包含进位/借位标志CF、零标志zF和符号标志NF。假定为该机设计了条件转移指令,其格式如下:其中,00000为操作码OP;C、Z和N分别为CF、ZF和NF的对应检测位,某检测位为1时表示
下列各选项中的两函数相等的是().
A、 B、 C、 D、 A照片中有一群人在室内,有一个看着前面电脑的女性的背影,因此正确答案是(A)项。尽管照片中有很多客人(customers),但是有很多空座位。因此(B)项是错误的。如果听到librar
FrommyinfancyIwasnotedforthedocilityandhumanityofmydisposition.Mytendernessofheartwasevensoconspicuousast
最新回复
(
0
)