pathy wrote:
2-1 SECTION A 21-27
The energy contained in rock within the earth’s crust represents a nearly unlimited energy source, but until recently commercial retrieval has been limited to underground hot water and/or steam recovery systems. These systems have been developed in areas of recent volcanic activity, where high rates of heat flow cause visible eruption of water in the form of geysers and hot springs. In other areas, however, hot rock also exists near the surface but there is insufficient water present to produce eruptive phenomena. Thus a potential hot dry rock (HDR) reservoir exists whenever the amount of spontaneously produced geothermal fluid has been judged inadequate for existing commercial systems.
As a result of recent energy crisis, new concepts for creating HDR recovery systems—which involve drilling holes and connecting them to artificial reservoirs placed deep within the crust—are being developed. In all attempts to retrieve energy from HDR’s, artificial stimulation will be required to create either sufficient permeability or bounded flow paths to facilitate the removal of heat by circulation of a fluid over the surface of the rock.
The HDR resource base is generally defined to included crustal rock that is hotter than 150℃, is at depths less than ten kilometers, and can be drilled with presently available equipment. Although wells deeper than ten kilometers are technically feasible, prevailing economic factors will obviously determine the commercial feasibility of wells at such depths. Rock temperatures as low as 100℃ may be useful for space heating; however, for producing electricity, temperatures greater than 200℃ are desirable.
The geothermal gradient, which specifically determines the depth of drilling required to reach a desired temperature, is a major factor in the recoverability of geothermal resources. Temperature gradient maps generated from oil and gas well temperature-depth records kept by the American Association of Petroleum Geologists suggest that tappable high-temperature gradients are distributed all across the United States. (There are many areas, however, for which no temperature gradient records exist.)
Indications are that the HDR resource base is very large. If an average geothermal temperature gradient of 22℃ per kilometer of depth is used, a staggering 13,000,000 quadrillion B.T.U.’s of total energy are calculated to be contained in crustal rock to a ten-kilometer depth in the United States. If we conservatively estimate that only about 0.2 percent is recoverable, we find a total of all the coal remaining in the United States. The remaining problem is to balance the economics of deeper, hotter, more costly wells and shallower, cooler, less expensive wells against the value of the final product, electricity and/or heat.
1. The primary purpose of the passage is to
(A) alert readers to the existence of HDR’s as an available energy source
(B) document the challengers that have been surmounted in the effort to recover energy from HDR’s
(C) warn the users of coal and oil that HDR’s are not an economically feasible alternative
(D) encourage the use of new techniques for the recovery of energy from underground hot water and steam
(E) urge consumers to demand quicker development of HDR resources for the production of energy
2. The passage would be most likely to appear in a
(A) petrological research report focused on the history of temperature-depth records in the United States
(B) congressional report urging the conservation of oil and natural gas reserves in the United States
(C) technical journal article concerned with the recoverability of newly identified energy sources
(D) consumer report describing the extent and accessibility of remaining coal resources
(E) pamphlet designed to introduce homeowners to the advantages of HDR space-heating systems
3. According the passage, an average geothermal gradient of 22℃ per kilometer of depth can be used to
(A) balance the economics of HDR energy retrieval against that of underground hot water or steam recovery systems
(B) determine the amount of energy that will used for space heating in the United States
(C) provide comparisons between hot water and HDR energy sources in United States
(D) revise the estimates on the extent of remaining coal resources in the United States
(E) estimate the total HDR resource base in the United States
4. It can be inferred from the passage that the availability of temperature-depth records for any specific area in the United States depends primarily on the
(A) possibility that HDR’s may be found in that area
(B) existence of previous attempts to obtain oil or gas in that area
(C) history of successful hot water or steam recovery efforts in that area
(D) failure of inhabitants to conserve oil gas reserves in that area
(E) use of coal as a substitute for oil or gas in that area
5. According to the passage, in all HDR recovery systems fluid will be necessary in order to allow
(A) sufficient permeability
(B) artificial stimulation
(C) drilling of holes
(D) construction of reservoirs
(E) transfer of heat
6. According to the passage, if the average geothermal gradient in an area is 22℃ per kilometer of depth, which of the following can be reliably predicted?
I. The temperature at the base of a 10-kilometer well will be sufficient for the production of electricity.
II. Drilling of wells deeper than 10 kilometers will be economically feasible.
III. Insufficient water is present to produce eruptive phenomena.
(A) I only
(B) II only
(C) I and II only
(D) II and III only
(E) I, II, and III
7. Which of the following would be the most appropriate title for the passage?
(A) Energy from Water Sources: The Feasibility of Commercial Systems
(B) Geothermal Energy Retrieval: Volcanic Activity and Hot Dry Rocks
(C) Energy Underground: Geothermal Sources Give Way to Fossil Fuels
(D) Tappable Energy for America’s Future: Hot Dry Rocks
(E) High Geothermal Gradients in the United States: Myth or Reality?
para1
energy source contained in rock from two kinds of area:
(1) recent volcanic activity eruption, underground hot
water—hot spring, steam recovery system
(2) other areas: insufficient water to produce eruption
then introduce into the main theme: HDR reservoir
para2
new concept of creating HDR recovery systems—involve drilling holes and connecting them to artificial reservoirs
retrieve energy from HDR: require artificial simulation
para3
HDR resource base—discuss about two factors included in the consideration which will affect HDR resource base: depth & temperature
para4
further discuss/combine two factors in para3 by using “geothermal gradient” & “temperature gradient” these two techniques for example
para5
using geothermal temperature gradient combined in para4 for example to estimate the extent to which HDR resource could be utilized and state the difficulty to balance between economic concerns as the ending of the whole passage
1. The primary purpose of the passage is to
(A) alert readers to the existence of HDR’s as an available energy source
….correct
(B)
document the challengers that have been surmounted in the effort to recover energy from HDR’s
the primary purpose of the passage does not to document anything
(C)
warn the users of coal and oil that HDR’s are not an economically feasible alternative
the primary purpose of the passage does not to warn users
(D)
encourage the use of new techniques for the recovery of energy from underground hot water and steam
no encourage mention in the passage
(E)
urge consumers to demand quicker development of HDR resources for the production of energy
no urge mention in the passage
2. The passage would be most likely to appear in a
(A) petrological research report focused on the history of temperature-depth records in the United States
….incorrect
“history of temperature-depth records”only cover part of the passage
(B) congressional report urging the conservation of oil and natural gas reserves in the United States
congressional report---not fit to the theme of the passage
(C) technical journal article concerned with the recoverability of newly identified energy sources
….correct
best fit to the passage’s main idea than (A)
(D) consumer report describing the extent and accessibility of remaining coal resources
consumer report---not fit to the theme of the passage
(E) pamphlet designed to introduce homeowners to the advantages of HDR space-heating systems
see last sentence in para3 from below:
Rock temperatures as low as 100℃ may be useful for space heating; however, for producing electricity, temperatures greater than 200℃ are desirable.
thus space-heating systems is only part of the passage
3. According the passage,
an average geothermal gradient of 22℃ per kilometer of depth can be used to
(A) balance the economics of HDR energy retrieval against that of underground hot water or steam recovery systems
….incorrect
recently commercial retrieval has been limited to underground hot water and/or steam recovery systems:para1
retrieve energy from HDR:para2
an average geothermal gradient of 22℃ per kilometer of depth:para5
choice (A) cannot connect to what the question stem ask
(B) determine the amount of energy that will used for space heating in the United States
….incorrect
see last sentence in para3 from below:
Rock temperatures as low as 100℃ may be useful for space heating; however, for producing electricity, temperatures greater than 200℃ are desirable.
not related to what the question stem ask, these two sentences---
question stem & option(B) are two different issues appear in the different paragraph to the passage
(C) provide comparisons between hot water and HDR energy sources in United States
….out of scope
nowhere in the passage does the author intend to “compare between hot water and HDR energy sources”, and it is
only in para1 the passage states that hot underground water could bring to the existence of HDR
(D) revise the estimates on the extent of remaining coal resources in the United States
….incorrect
see sentences in para5 below:
If
an average geothermal temperature gradient of 22℃ per kilometer(1)of depth is used, a staggering 13,000,000 quadrillion B.T.U.’s of total energy are calculated to be contained in crustal rock to a ten-kilometer depth in the United States.
If
we conservatively estimate that only about 0.2 percent is recoverable, we find a total of all the coal remaining(2)in the United States.
(1)&(2) is two different things, also nowhere in the passage mention about “revise” the estimates on coal remaining
(E) estimate the total HDR resource base in the United States
….correct
see sentence below and notice how each piece of information relate to other, then you can assure (E) be the correct answer:
Indications are that
the HDR resource base is very large.
If(used for estimate)
average geothermal temperature gradient of 22℃ per kilometer of depth is used, a staggering 13,000,000 quadrillion B.T.U.’s of total energy are calculated to be contained in crustal rock to a ten-kilometer depth in the United States.
4. It can be inferred from the passage that the availability of temperature-depth records for any specific area in the United States depends
primarily on the
(A) possibility that HDR’s may be found in that area
(B) existence of previous attempts to obtain oil or gas in that area
….correct
….best fit to the question stem
Only in para4 does the author mention about
temperature-depth records:
The geothermal gradient, which specifically determines the depth of drilling required to reach a desired temperature, is a major factor in the recoverability of geothermal resources. Temperature gradient maps
generated from oil and gas well temperature-depth records kept by the American Association of Petroleum Geologists suggest that tappable high-temperature gradients are distributed all across the United States. (There are many areas, however, for which no temperature gradient records exist.)
and it is only from this sentence in para4 we know temperature-depth records generated from/depend on oil and gas well
(C) history of successful hot water or steam recovery efforts in that area
(D) failure of inhabitants to conserve oil gas reserves in that area
(E) use of coal as a substitute for oil or gas in that area
5. According to the passage, in
all HDR recovery systems fluid will be necessary in order to allow
(A) sufficient permeability
…...incorrect
In all attempts to retrieve energy from HDR’s, artificial stimulation will be required to create either sufficient permeability or bounded flow paths to facilitate the removal of heat by circulation of a fluid over the surface of the rock.
It is by“circulation of a fluid over the surface of the rock” that the creation of “sufficient permeability” can facilitate the removal of heat, not “fluid” will be necessary to allow “sufficient permeability”
(B) artificial stimulation
……trap choice, incorrect
In all attempts to retrieve energy from HDR’s,
artificial stimulation will be required to create either sufficient permeability or bounded flow paths to
facilitate the removal of heat by circulation of a fluid over the surface of the rock.
It is artificial stimulation---->fluid rather than fluid---->artificial stimulation
(C) drilling of holes
……incorrect
As a result of recent energy crisis, new concepts for creating HDR recovery systems—which involve drilling holes and connecting them to artificial reservoirs placed deep within the crust—are being developed.
It is not that fluid will be necessary in order to allow drilling of holes, drilling holes is just part of the HDR recovery systems
(D) construction of reservoirs
….incorrect
See para1
Thus a potential hot dry rock (HDR) reservoir exists whenever the amount of spontaneously produced geothermal fluid has been judged inadequate for existing commercial systems.
if this choice is correct, then
fluid will be necessary in order to allow--- construction of reservoirs
but the passage only says HDR reservoir exists whenever fluid has been judged inadequate….
(E) transfer of heat
….correct
As a result of recent energy crisis, new concepts for creating
HDR recovery systems—which involve drilling holes and connecting them to artificial reservoirs placed deep within the crust—are being developed. In all attempts to retrieve energy from HDR’s, artificial stimulation will be required to create either sufficient permeability or bounded flow paths
to facilitate the removal of heat by circulation of a fluid over the surface of the rock.
6. According to the passage, if the average geothermal gradient in an area is 22℃ per kilometer of depth, which of the following can be reliably predicted?
I. The temperature at the base of a 10-kilometer well will be sufficient for the production of electricity.
Indications are that the HDR resource base is very large. If an average geothermal temperature gradient of 22℃ per kilometer of depth is used, a staggering 13,000,000 quadrillion B.T.U.’s of total energy are calculated to be contained in crustal rock to a ten-kilometer depth in the United States.
II. Drilling of wells deeper than 10 kilometers will be economically feasible.
The remaining problem is to balance the economics of deeper, hotter, more costly wells and shallower, cooler, less expensive wells against the value of the final product, electricity and/or heat.
III. Insufficient water is present to produce eruptive phenomena.
“In other areas, however, hot rock also exists near the surface but there is insufficient water present to produce eruptive phenomena.” is in para1
However
“the average geothermal gradient in an area is 22℃ per kilometer of depth” appear in para5
Not relate to each other
(A) I only ….correct
(B) II only
(C) I and II only
(D) II and III only
(E) I, II, and III
7. Which of the following would be the most appropriate title for the passage?
(A) Energy from Water Sources: The Feasibility of Commercial Systems
….out of scope
(B) Geothermal Energy Retrieval: Volcanic Activity and Hot Dry Rocks
….out of scope, "Geothermal Energy Retrieval" is only part of the whole theme
(C) Energy Underground: Geothermal Sources Give Way to Fossil Fuels
….out of scope
(D) Tappable Energy for America’s Future: Hot Dry Rocks
….correct
….best fit to the title of the passage, HDR is the focus of the whole passage
(E) High Geothermal Gradients in the United States: Myth or Reality
….too narrow, “High Geothermal Gradients”only cover part of the passage
close
19 Jan 2020, 21:23
53%
(03:25) wrong 
