The first discovery and significance of liquid mercury in a thermal

Subscriber access provided by EKU Libraries

Fossil Fuels

The first discovery and significance of liquid mercury in a thermal simulation experiment on humic kerogen Weilong Peng, Quanyou Liu, Ziqi Feng, Chenchen Fang, Deyu Gong, Peng Li, Yue Lyu, and Pengwei Wang Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.8b03294 • Publication Date (Web): 02 Jan 2019 Downloaded from http://pubs.acs.org on January 12, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

The first discovery and significance of liquid mercury in a thermal

2

simulation experiment on humic kerogen

3

Weilong Peng†, ‡, §, Quanyou Liu*, †, ‡, Ziqi Feng*, #,&, Chenchen Fang§, Deyu Gong§, Peng Li†, Yue

4

Lyu§, Pengwei Wang‡

5

†

6

Beijing 100083, China

7

‡

Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China;

8

§

Research Institute of Petroleum Exploration and Development, PetroChina, Beijing, 100083, China

9

# School

State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, SINOPEC,

of Geosciences, China University of Petroleum, Qingdao, 266580, China

10

&

11

Qingdao, 266071, China

Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology,

12 13

Abstract: We firstly found enriched liquid mercury beads in a thermal simulation

14

experiment on humic kerogen extracted from coal, which provided some kind of direct

15

evidence that mercury can be released from coal measure during maturation. In the

16

simulation experiment, mass distribution of liquid mercury beads is between 0.0083 g

17

and 0.2242 g; their content in simulated gas range from 372.5 ng/m3 to 2776.3 ng/m3;

18

and their yields was from 0.3102 ×10−3 g/g to 7.4312 ×10−3 g/g sample. Along with this

19

thermal simulation experiment and previous studies, three genetic models of mercury

20

in gas reservoirs are summarized: source-rock controlling type, fault-controlling type,

21

and source-rock/fault joint controlling type. Mercury in source-rock-controlling gas

22

reservoirs is mainly derived from source rocks, which are generally coal measures. 1

ACS Paragon Plus Environment

Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

Mercury in fault-controlling gas reservoirs is mainly derived from deep geologic fluids,

2

with relatively small contribution from source rocks. The transitional source-rock/fault

3

joint controlling type mainly develops in tectonic activity zones where source rocks can

4

be either sapropelic or humic. Liquid mercury collected for the first time in simulation

5

experiment has important theoretical significance for the exploration and development

6

of natural gas, as well as important practical significance for the prevention of mercury

7

accidents in natural gas exploration and production.

8

Keywords: Mercury; Thermal simulation experiment; Humic kerogen; Natural gas;

9

Thermal maturation

10

1. Introduction

11

Natural gas as widely distributed huge reserves of emerging green energy, has

12

gained widespread attention in recent years;1 all three fossil fuels (natural gas, oil and

13

coal) primary originate from organic matters, with similar origins and locations.2 The

14

organic matters, under the influence of heat, pressure and time, form coal, oil and

15

natural gas.3 The mineral matter and solids partition to the oil and coal, leaving the

16

majority of volatile contaminants such as mercury, sulfur and moisture remaining in

17

the natural gas.2 The trace levels of mercury presented in natural gas are of important

18

scientific research significance because they have caused failures of the aluminum heat

19

exchangers in gas processing plants.4, 5 Mercury amalgamates with aluminum, resulting

20

in a mechanical failure and gas leakage.6 Mercury is a volatile liquid metal under

21

normal temperature and pressure, and it does not react easily with other substances.6−10

22

In the 1960s, Japanese residents in the Kumamoto Prefecture experienced heavy 2


Page 2 of 33

Page 3 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

casualties due to industrial mercury poisoning.11−15 As an important strategic material

2

for energy, natural gas has attracted increasing attention. However, the mercury in

3

natural gas not only pollutes the environment, but also endangers human health.16−21

4

The corrosion of mercury in natural gas production equipment causes huge direct

5

economic losses.6

6

There are still two primary opinions on the source of mercury in natural gas.21, 22

7

Han et al. (2010)23and Li et al. (2012)24 analyzed the relationship between mercury

8

content in Chinese natural gas, source rocks and concluded that mercury in natural gas

9

mainly came from source rocks, especially coal measures. Tu. (1985)25, Zettlitzer et al.

10

(1997)26 and Hou et al. (2005)21believed that mercury in natural gas primarily came

11

from the deep crust. Although many scholars have detected the presence of mercury in

12

natural gas,27−30 a consensus has not yet reached whether the mercury in natural gas can

13

be directly derived from the maturation process of organic matter.21, 25, 26 Furthermore,

14

there is no public literature on studying mercury from the perspective of a thermal

15

simulation experiment on organic matter. Being able to confirm that mercury can be

16

released from the maturation of organic matter via thermal simulation would be the

17

most direct evidence that mercury in natural gas can derived from the source rock.

18

Understanding the source of mercury in natural gas and whether the maturation process

19

of source rock can release mercury has great scientific significance for preventing

20

mercury poisoning and gas-production accidents, and for reducing mercury pollution

21

in the environment.

22

To date, there are few papers on about the formation mechanism of mercury in gas 3


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

reservoirs. Previous studies merely focused on mercury content in petroleum and coal.23,

2

25, 31

3

maturation of humic organic matter and mercury with a thermal simulation experiment

4

to further understand the source of mercury in natural gas and the genetic model of

5

mercury in gas reservoirs.

6

2. Sample and experimental method

7

2.1. Sample

This paper, however, for the first time investigated the relationship between the

8

The sample was collected from the Shaping Coal Mine in the northeastern margin

9

of the Ordos Basin, China (Fig. 1), which is located in Hequ County, Shanxi Province.

10

Before the thermal simulation experiment, we carried out the grinding and extraction

11

of kerogen for the coal sample. Low-maturity source rocks can better reflect the

12

maturation process of organic matter in the thermal simulation experiment. Therefore,

13

the vitrinite Ro of the sample was 0.55%. The maceral group analysis of the kerogen

14

showed that the contents of vitrinite, exinite, and inertinite were 85%, 5%, and 10%,

15

respectively. The maceral group contained no sapropelite, and organic matter was

16

typical humic kerogen (Fig. 2). Rapid pyrolysis was carried out to obtain the

17

geochemical parameters of the sample. Total organic carbon (TOC) content of the

18

sample was 58.30%. Maximum pyrolysis temperature (Tmax) was 424ºC. The quantity

19

of free hydrocarbons (S1 peak) and the amount of hydrocarbons generated during the

20

thermal cracking of kerogen in the rock (S2 peak) were 0.66 mg/g and 97.18 mg/g,

21

respectively (Table 1).

22

2.2. Experimental method 4


Page 4 of 33

Page 5 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

All analysis (including extraction of kerogen in coal, thermal simulation

2

experiment, gas components, mercury content in gas, carbon and hydrogen isotopic

3

compositions) were completed in the Key Laboratory of Petroleum Geochemistry of

4

the Research Institute of Petroleum Exploration and Development, PetroChina. We will

5

briefly describe the major experimental methods and steps below.

6

2.2.1 Thermal simulation experiment

7

The schematic diagram of the thermal-simulation experimental device is shown in

8

Figure 3. The experimental apparatus mainly consists of a reaction device, a control

9

device, and a collection device. The thermal simulation experiment required lithostatic

10

pressure, and we placed the sample (kerogen) in the autoclave. Before the experiment,

11

the whole system was vacuum-pumped and then was sealed off. Twelve temperature

12

points were designated in the experiment (Table 2). The temperature control procedure

13

of the autoclave was programmed: the autoclave temperature was raised from 18ºC

14

(room temperature) to 232ºC in 10 min and then maintained at 232ºC for 10 min; then,

15

the autoclave temperature was raised from 232ºC to the target temperature of 5ºC/min,

16

which was maintained for 3 days (4320 min). Finally, the temperature of the autoclave

17

was quickly decreased to 232ºC and maintained at that temperature until the

18

experimental product was collected.

19

It is worth noting that the cold trap was transferred to −4ºC before the collection

20

of the products. The gas–liquid separation device was used to collect the liquid products

21

and let the gaseous products pass through it into a glass bottle. The gas product was

22

collected by drainage method. After the gas collection, dichloromethane was added to 5


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

the gas–liquid separator for the protection of liquid hydrocarbons and mercury. Gas

2

products were collected and sealed in two glass bottles. One bottle was used to analyze

3

gas components and isotopic compositions; the other was used to analyze the content

4

of mercury in gas. The remaining gas was used for quantification and then treated to

5

prevent pollution. After the collection of gas products, liquid mercury would gather in

6

the gas–liquid separator and then could be collected through filtration and weighed.

7

2.2.2 Chemical components analysis

8

The components of natural gas were measured by HP7890A gas chromatograph

9

(GC) equipped with a flame ionization detector. Every single component was separated

10

by a capillary column (PLOT Al2O3 50 m × 0.53 mm). The GC oven temperature was

11

set at 33 ºC for 10 min at the beginning, then increased to 180 ºC at the rate of 10 ºC/min

12

and finally maintained at the maximum temperature for 20−30 min.

13

2.2.3 Stable carbon and hydrogen isotope analysis

14

Stable carbon isotope analysis of gas was carried out by isotope mass spectrometer.

15

Gas components were first separated by GC, then converted into carbon dioxide and

16

injected into mass spectrometer, and individual component is separated by

17

chromatographic column. The GC oven temperature was raised up from 33ºC to 80ºC

18

at 8ºC/min, then from 80ºC to 250 ºC at 5ºC/min. The final temperature was maintained

19

for 10 min. Every sample was measured 3 times then averaged with the standard of

20

VPDB and precision of ±0.3‰. Natural gas hydrogen isotope analysis was conducted

21

on a MAT253 isotopic mass spectrometer with the method of GC/TC/IRMS. Helium

22

was the carrier gas. Components separation of natural gas were conducted within a HP6


Page 6 of 33

Page 7 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

PLOT Q column (30 m × 0.32 mm × 20 μm). The initial oven temperature was started

2

with 33ºC, and raised to 80ºC at the rate of 8 ºC/min, then ramped up to 250ºC at the

3

rate of 5ºC/min. Every sample was measured 3 times and averaged, with the standard

4

of VSMOW and the precision of ±5‰. Detailed descriptions of analyses method and

5

process can be found in works by Dai et al. (2012)32 and Huang et al. (2015)33.

6

3. Results

7

In this paper, we analyzed the composition of simulated gas and the isotopic

8

composition of methane. Specific experimental data are shown in Table 2. The amount

9

of mercury in coal varies greatly but, generally, is higher than other sedimentary rocks.6,

10

21, 22

11

of the simulation experiment of the hydrocarbon generation from humic kerogen. The

12

mercury collected and the yield of mercury was quantitatively calculated; and finally

13

the mercury content in natural gas was analyzed.

14

3.1. Chemical and isotopic composition of natural gas

15

Enrichment state of liquid mercury beads were found for the first time as a result

Gas generated in the simulated experiment can be divided into hydrocarbon gas

16

and nonhydrocarbon gas. Hydrocarbon gas mainly includes methane and its homologue;

17

nonhydrocarbon gas mainly includes N2, H2, CO, and CO2 (Table 2). Hydrocarbon gas

18

is dominated by CH4; nonhydrocarbon gas is dominated by CO2.

19

At 320ºC, the content of CH4 is 10.65%; at 550ºC, CH4 content increases to

20

90.24%, and the corresponding dryness coefficient (C1/C1−5) increases from 0.601 to

21

0.994, when the natural gas transformed from wet gas to dry gas. The content of CH4 7


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

increases gradually with increasing temperature (gas leakage exists at 440ºC, so the gas

2

component at 440ºC is merely a reference). At 320ºC, the content of CO2 is 74.90%; at

3

550ºC, CO2 content decreases to 4.71%. The δ13C1 value first decreases, and then

4

increases and gradually stabilizes. The δ13C1 value distribution ranges from the initial

5

−33.0‰ to −24.1‰ (Fig. 4a). The δD1 value increases gradually with increasing

6

temperature, and the δD1 value ranges from −300‰ to −134‰ (Fig. 4b).

7

3.2. Mercury in thermal simulation experiment

8

The chemical properties of mercury are relatively stable and does not easily react

9

with other substances. Mercury, which is highly toxic and volatile, is difficult to collect

10

in simulated experiments. We designed 12 temperature points in the simulation

11

experiment and collected liquid mercury beads at 7 temperature points. In the

12

experiment, the mass distribution of liquid mercury beads ranges from 0.0083 g to

13

0.2242 g (Fig. 5), and the corresponding yield of liquid mercury ranges from

14

0.3102×10−3 g/g to 7.4312×10−3 g/g kerogen (Fig. 6, Table 2). The maximum diameter

15

of a liquid mercury bead is over 2 mm. Content of mercury in the gas is distributed

16

between 372.5 ng/m3 and 2776.3 ng/m3 (Table 2).

17

4. Discussion

18

Previous studies on mercury content in coal have been carried out. The mercury

19

content of coals are typically around 0.1 ppm.12, 20 In this paper, we discovered mercury

20

in enriched state through simulation experiment for the first time.

21

4.1. Significance of alkane characteristics for liquid mercury

8


Page 8 of 33

Page 9 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

A lot of thermal simulation experiments on organic matter have been done by

2

previous studies.34−40 The thermal simulation experiment can be divided into open,

3

semi-open, and closed systems, according to experimental conditions.41 Samples of

4

thermal simulation experiment include dark mudstone,42 coal,37,

5

kerogen,40 and humic kerogen.44,

6

simulation experiment and analyzed the simulated gas components together with

7

carbon and hydrogen isotopic composition of methane. In accordance with previous

8

experimental results,34−39,

9

experimental temperature. However, in our simulation experiment, gas leakage existed

10

at 440ºC, rendering the methane component abnormal (Fig. 7, Table 2). Gas leakage at

11

440ºC is the cause of malfunction of the experiment. There is only one temperature

12

point (440ºC) where the failure occurs. Because it does not affect the integrity of the

13

experiment, the temperature point has not been redone. The other groups of methane

14

content collected at the varying temperature points are in accordance with the dynamic

15

model of thermal maturation of organic matter.43, 47−50

46

45

39, 43

sapropelic

We collected the gas products of the thermal

alkane content should increase with increasing

16

With the increasing temperature, alkane gas shows obvious isotopic fractionation

17

(Fig. 4). The carbon isotopic value of methane first decreases and then increases with

18

increasing temperature (Fig. 4a). Hydrogen isotopic value of methane tend to increase

19

with increasing temperature (Fig. 4b). Geochemical characteristics of the collected gas

20

in our thermal stimulation experiment generally conform to the organic-matter

21

maturation-dynamics model established by previous studies,49, 51 which indicates that

22

our thermal stimulation experiment is generally appropriate and that studying mercury 9


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

in natural gas using an organic-matter thermal-simulation experiment is feasible.

2

Unfortunately, the evolution rule of mercury yield during the thermal maturation

3

of organic matter has not been found in this study. There are abrupt changes in mercury

4

yield at several temperature points, which may be due to the high volatility of mercury

5

and the difficulty in collecting it. Subsequent research on mercury is still under way.

6

Mercury can cause great pollution to the environment, 11−14 so it is very important to

7

carry out the geochemical investigation of mercury.

8

4.2. Discovery and significance of liquid mercury beads

9

The three existing states of mercury in coal are (1) adsorption state of the monomer;

10

(2) inorganic compounds, such as HgS and HgO;52−54 and (3) organic compounds, such

11

as a long chain compound of mercury.55−58 Our experimental samples are kerogen

12

extracted from coal, so there is no mercury in the form of inorganic compounds. The

13

source of liquid mercury can only be the adsorption of mercury in the monomer state

14

or the mercury element transformed from organic compound. Since the mass of liquid

15

mercury collected in our study is relatively heavy, we believe that a considerable

16

amount of mercury may be derived from organic compounds of mercury. The content

17

of organic mercury compounds in source rocks may be much larger than we thought.

18

Source rocks can indeed provide important sources for mercury in natural gas, but it is

19

undeniable that deep geologic fluids may also provide material basis for mercury

20

enrichment in natural gas.

21

Groningen Gas Field is a typical example of high mercury content in natural gas,

22

the field’s development in the Late Jurassic–Early Cretaceous was frequently 10


Page 10 of 33

Page 11 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

accompanied by magmatic activity that continued until the end of the Neogene.59

2

Magmatic activity may be an important reason for the high mercury content in the gas

3

field, that is, the mercury content in the gas field may have originated from deep fluids.

4

The investigation of Huang et al. (2015)60 into mercury content in magma-altered coal

5

measures in southern China showed that mercury content of the coal measures near the

6

alteration increased obviously, which further illustrated that magmatic hydrothermal

7

fluids can be potentially rich in mercury and the deep fluids may also be a source for

8

mercury in natural gas. The mercury content in coal may be quite high. On the one

9

hand, the combustion of coal directly pollutes the environment, on the other hand, coal

10

as a source rock of natural gas, enriches mercury in natural gas and causes potential

11

environmental pollution.

12

On the basis of our thermal simulation experiment and the findings of previous

13

studies59, 60, 61, we propose three basic genetic models of mercury gas reservoirs (Fig.

14

8):

15

(1) Source-rock controlling type (Fig. 8a). The mercury in this gas reservoir is

16

mainly derived from maturation process of source rocks. Mercury is transported with

17

natural gas to trap. This type of gas reservoir may be developed mainly in the craton

18

basin. The basin is relatively stable, with little development of deep faulting system and

19

a lack of magmatic activity. The source rock is usually of humic organic matter. The

20

Ordos Basin in China belongs to a stable craton basin. There are no deep faults in the

21

basin and coal measures are well developed. Therefore, the mercury content in gas

22

reservoirs in the basin may be mainly affected by source rocks. 11


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

(2) Fault-controlling type (Fig. 8b). Mercury in this type of gas reservoir may be

2

derived mainly from deep fluids (including magmatic activity). The mercury in the deep

3

fluids is transported to gas reservoirs through faults and other migration systems. This

4

type of gas reservoir is developed mainly in foreland basins and rift basins which have

5

relatively intense tectonic activities and magmatic activities. The content of organic

6

matter in the source rocks are mostly sapropelic. In the Liaohe Basin of China, the

7

deeper the gas reservoir is buried, the higher the mercury content is.23 The basin belongs

8

to a rift basin with well-developed faults, so the mercury content in the gas reservoirs

9

in the basin may be more affected by deep fluids.

10

(3) Source-rock/fault joint controlling type (Fig. 8c). This type of gas reservoir is

11

a transition between the previous two types. The mercury in this gas reservoir is derived

12

from source rock and deep fluids. Source rocks can be both sapropelic and humic. Since

13

the fault is relatively developed, this type of gas reservoir is also developed mainly in

14

a foreland basin or rift basin where strong tectonic activities are present.

15

Because fluids may contain a large amount of mercury or mercury-containing

16

compounds, they can have a great impact on the mercury content in gas reservoirs.

17

Therefore, compared with source rocks, fluids may have a greater impact on the

18

mercury content in gas reservoirs.62 Mercury concentrations in the natural gases of

19

different structural units vary a lot. For example, the highest mercury concentration

20

Southwest Depression of the Tarim Basin China was found in the zone of strong

21

structural activities, with an average of mercury content in the natural gas of 156095.57

22

ng/m3.63 The genetic model of mercury in the three kinds of gas reservoirs is of great 12


Page 12 of 33

Page 13 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

significance in understanding the source of mercury in natural gas and preventing

2

mercury-poisoning accidents in natural gas exploration and development.

3

5. Conclusion

4

In the thermal simulation experiment of hydrocarbon generation from kerogen,

5

liquid mercury beads in an enriched state are discovered for the first time, providing

6

some kind of direct evidence that mercury can be released from coal-derived source

7

rocks during maturation. Contents of mercury in simulated gas range from 372.5 ng/m3

8

to 2776.3 ng/m3. The simulation experiment shows mass distribution of liquid mercury

9

beads between 0.0083 g and 0.2242 g; and yields of liquid mercury distributes from

10

0.3102 ×10−3 g/g to 7.4312 ×10−3 g/g kerogen. Combined with simulation experiments

11

and previous studies, we proposes three basic genetic models of mercury in gas

12

reservoirs: source-rock controlling type, fault-controlling type, and source-rock/fault

13

joint controlling type. Mercury in the source-rock-controlling type of gas reservoir is

14

derived mainly from source rocks, which are primarily coal measures. Mercury in fault-

15

controlled gas reservoirs is derived mainly from deep fluids. Mercury in source rocks

16

contributes relatively less to gas reservoirs and generally develops in tectonic active

17

zones. The source-rock/fault joint controlling type is the transition between the previous

18

two types, and sources rock can be both sapropelic type and humic type.

19 20

Corresponding Authors

21

*E-mail: [email protected]

22

*E-mail: [email protected] 13


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1 2

Notes

3

The authors declare no competing financial interest.

4 5

ORCID

6

Weilong Peng: 0000-0003-3608-3170

7 8

Acknowledgements

9

We would like to thank Prof. Jinxing Dai, academician of the Chinese Academy

10

of Sciences, for his generous guidance and supervision, and Prof. Jingkui Mi for his

11

providing sample. Thanks to Academician Yongsheng Ma from Chinese Academy of

12

Engineering for his concern and help to the authors.We also appreciate the guidance of

13

the laboratory staff from the National Key Laboratory of petroleum geochemistry of

14

Research Institute of Petroleum Exploration and Development of PetroChina in the

15

process of experiment. This work is financially supported by the China National

16

Science & Technology Special Project (Grant No. 2016ZX05007-01), the Strategic

17

Priority Research Program of Chinese Academy of Sciences (Grant No.

18

XDA14010404), and the National Natural Science Foundation of China (Grant No:

19

41625009, 41802161).

20

References

21

(1) Zhao, D.; Wang W. Clean development mechanism and gas distributed energy 14


Page 14 of 33

Page 15 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

stations in China. Natural Gas Industry 2005, 25(11), 119−122 (in Chinese with

2

English abstact).

3 4 5 6

(2) Chen, J.; Shao, Z.; Qin, Y. Energy geology. China University of Mining and Technology Press, Jiangsu, 2004, pp. 1−316 (In Chinese). (3) Qin, Y. An introduction to fossil energy geology. China University of Mining and Technology Press, Jiangsu, 2017, pp. 1−426 (In Chinese).

7

(4) Mcnamara, J.D.; Wagner, N.J. Process effects on activated carbon performance and

8

analytical methods used for low level mercury removal in natural gas applications.

9

Gas Separation & Purification 1996, 10(2), 137−140.

10

(5) Coade, R.; Coldham, D. The interaction of mercury and aluminium in heat

11

exchangers in a natural gas plants. International Journal of Pressure Vessels and

12

Piping 2006, 83(5), 336−342.

13

(6) Li, J.; Yan, Q.; Tang, D. Formation mechanism and distribution prediction of

14

mercury in natural gas. Geological Publishing House, Beijing, 2011, pp, 1−180 (in

15

Chinese).

16

(7) Ehmann, W.D.; Lovering, J.F. The abundance of mercury in meteorites and rocks

17

by neutron activation analysis. Geochimica et Cosmochimica Acta 1967, 31(3),

18

357−376.

19 20

(8) Carmeron, E.M.; Jonasson, I.R. Mercury in Precambrain shales of the Canadian Shield. Geochimica et Cosmochimica Acta 1972, 36(9), 985−1005.

21

(9) Varekamp, J.C.; Buseck, P.R. The speciation of Hg in hydrothermal systems, with

22

applications for ore deposition. Geochimica et Cosmochimica Acta 1984, 48(7), 15


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

177−185.

2

(10) Christopher, N.S.; Stephen, E.K.; Joel, D.B.; James, J.R. Isotope geochemistry of

3

mercury in source rocks, mineral deposits and spring deposits of the California

4

Coast Ranges, USA. Earth and Planetary Science Letters 2008, 269, 399−407.

5

(11) Harada, M. Minamata disease: Methylmercury poisoning in Japan caused by

6

environmental pollution. Critical Reviews in Toxicology 1995, 25(1), 1−24.

7

(12) Granite, E.J.; Pennline, H.W.; Hargis, R.A. Novel Sorbents for Mercury Removal

8

from Flue Gas. Industrial & Engineering Chemistry Research 2000, 39(4),

9

1020−1029.

10 11

(13) Granite, E.J.; Pennline, H.W. Photochemical Removal of Mercury from Flue Gas. Industrial & Engineering Chemistry Research 2002, 41(22), 5470−5476.

12

(14) Maroto-Valer, M.M.; Zhang, Y.; Gramite, E.J.; Tang Z. Pennline, H.W., Effect of

13

porous structure and surface functionality on the mercury capacity of a fly ash

14

carbon and its activated sample. Fuel 2005, 84, 105−108.

15

(15) Yuan, Q. Japan’s minamata disease event and environmental protest based on

16

political opportunity structure theory. Problem Studies 2016, 30(1), 47−56 (in

17

Chinese).

18 19 20 21 22

(16) Toole-O’Neil, B.; Tewalt, S.J.; Finkelman, R.B.; Akers, D.J. Mercury concentration in coal-unraveling the puzzle. Fuel 1999, 78, 47−54. (17) Galbreath, K.C.; Zygarlicke, C.J. Mercury transformations in coal combustion flue gas. Fuel Processing Technology 2000, 65(99), 289−310. (18) Laudal, D.L.; Brown, T.D.; Nott, B.R. Effects of flue gas constituents on mercury 16


Page 16 of 33

Page 17 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

speciation. Fuel Processing Technology 2000, 65(6), 157−165.

2

(19) Zhuang, Y.; Thompsom, J.S.; Zygarlicke, C.J.; Pavlish, J.H. Development of a

3

Mercury Transformation Model in Coal Combustion Flue Gas. Environmental

4

Science and Technology 2004, 38(21), 5803−5808.

5 6

(20) Granite, E.J.; Pennline, H.W.; Senior, C. Mercury control for coal-derived gas streams. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2015, pp. 1−445.

7

(21) Liang, Y.; Zhu, S.; Liang, H. Mercury enrichment in coal fire sponge in Wuda

8

coalfield, Inner Mongolia of China. International Journal of Coal Geology 2018,

9

192, 51−55.

10

(21) Hou, L.; Dai, J.; Hu, J.; Yu, Z. The variation and application of mercury content

11

for natural gases also state the mercury content rocks and soils. Natural Gas

12

Geoscience 2005, 16(4), 514−521 (in Chinese with English abstract).

13

(22) Liu, Q.; Dai, J.; Li, J.; Hou, L. Mercury in oil and natural gas and its critical

14

assessment. Petroleum Exploration and Development 2006, 33(5), 542−547 (in

15

Chinese with English abstract).

16

(23) Han, Z.; Yan, Q.; Wang, S.; Ge, S. Characteristics of natural gaseous mercury

17

concentration in Liaohe Depression, China. Acta Mineralogica Sinica 2010, 30(4),

18

508−511 (in Chinese with English abstract).

19

(24) Li, J.; Han, Z.; Yan, Q.; Wang, S.; Ge, S.; Wang, C. Genesis of mercury in natural

20

gas of Chinese gas fields. Natural Gas Geoscience 2012, 23(3), 413−418 (in

21

Chinese with English abstract).

22

(25) Tu, X. Preliminary study on mercury occurrence in source rocks. Acta 17


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

Sedimentolgica Sinica 1985, 3(1), 92−98 (in Chinese with English abstract).

2

(26) Zettlitzer, M.; Schöler, H.F.; Eiden, R.; Falter, R. Determination of Elemental,

3

Inorganic and Organic Mercury in North German Gas Condensates and Formation

4

Brines. Procedures of the International Symposium on Oil Field Chemistry 1997,

5

37260, 509−516.

6

(27) Schickling, G.; Broekaert, J. Determination of mercury species in gas condensates

7

by on line coupled high performance liquid chromatography and cold vapor atomic

8

absorption spectrometry. Applied Organomentallic Chemistry 1995, 9, 29−36.

9

(28) Bouyssiere, B.; Baco, F.; Savary, L.; Lobinski, R. Analytical Methods for

10

Speciation of Mercury in Gas Condensates: Critical Assessment and

11

Recommendations. Oil & Gas Science and Technology-Rev 2000, 55, 639−648.

12 13

(29) Wilhelm, S.M. Estimate of mercury emissions to the atmosphere from petroleum. Environment Science Technology 2001, 35, 4704−4710.

14

(30) Liu, Q.; Li, J.; Hou, L. Advance of research on mercury and its compounds

15

collecting and measuring methods. Natural Gas Geoscience 2006, 17(4), 559−565

16

(in Chinese with English abstract).

17

(31) Gou, Y.; Hou, D.; Wang, X. Source and Enrichment condition of mercury in

18

natural gas. Xinjiang Petroleum Geology 2009, 30(5), 582−584 (in Chinese with

19

English abstract).

20

(32) Dai, J.; Xia, X.; Li, Z.; Coleman, D.D.; Dias, R.F.; Gao, L.; Li, J.; Deev, A.; Li, J.;

21

Dessort, D.; Duclerc, D.; Li, L.; Liu, J.; Schloemer, S.; Zhang, W.; Ni, Y.; Hu, G.;

22

Wang, X.; Tang, Y. Inter-laboratory calibration of natural gas round robins for δ2H 18


Page 18 of 33

Page 19 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

and δ13C using off-line and on-line techniques. Chemical Geology 2012, 310−311,

2

49−55.

3

(33) Huang, S.; Fang, X.; Liu, D.; Fang, C.; Huang, T. Natural gas genesis and sources

4

in the Zizhou gas fields, Ordos Basin, China. International Journal of Coal Geology

5

2015, 152, 132−143.

6

(34) Barker, C. Calculated volume and pressure changes during thermal cracking of oil

7

to gas in reservoirs. American Association of Petroleum Geologists Bulletin 1990,

8

74(8), 1254−1261.

9

(35) Behar, F.; Kressmann, S.; Rudkiewicz, J.L.; Vandenbroucke, M.; Experimental

10

simulation in a confined system and kinetic modeling of kerogen and oil cracking.

11

Organic Geochemistry 1992, 19(1), 173−189.

12

(36) Behar, F.; Vandenbroucke, M.; Teermann S C.; Hatcher, P.G.; Leblond, C.; Lerat,

13

O. Experimental simulation of gas generation from coals and a marine kerogen.

14

Chemical Geology 1995, 126(3−4), 247−260.

15 16

(37) Tang, Y.; Jenden, P.D.; Nigrini, A.; Teerman, S.C. Modeling early methane generation in coal: Energy and Fuels 1996, 10, 659−671.

17

(38) Hill, R.J.; Zhang, E.; Katz, B.J.; Tang, Y. Modeling of gas generation from the

18

Barnett Shale, Fort Worth Basin, Texas. American Association of Petroleum

19

Geologists Bulletin 2007, 91(4), 501−521.

20

(39) Mi, J.; Zhang, S.; Chen, J.; He, K.; Liu, K.; Li, X.; Bi, L. Upper thermal maturity

21

limit for gas generation from humic coal. International Journal of Coal Geology

22

2015, 152, 123−131. 19


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

(40) Mi, J.; Zhang, S.; Su, j.; He, K.; Zhang, B.; Tian, H.; Li, X. The upper thermal

2

maturity limit of primary gas generated from marine organic matters. Marine and

3

Petroleum Geology 2018, 89, 120−129.

4

(41) Tang, Q.; Zhang, M.; Zhang, T.; Shang, H.; Lin, Y. A Review on Pyrolysis

5

Experimentation on Hydrocarbon Generation. Journal of Southwest Petroleum

6

University (Science & Technology Edition) 2013, 35(1), 52−62 (in Chinese with

7

English abstract).

8

(42) Wang, Y. Biomarkers from pindiquan (P2) shale by thermal modelling experiments.

9

Xinjiang Petroleum Geology 1992, 13(3), 240−250 (in Chinese with English

10

abstract).

11

(43) Liu, Q.; Liu, W.; Dai, j. Characterization of pyrolysates from maceral components

12

of Tarim coals in closed system experiments and implications to natural gas

13

generation. Organic Geochemistry 2007, 38, 921−934.

14

(44) Ma, X.; Zheng, G.; Sajjad, W.; Xu, W.; Fan, Q.; Zheng, J.; Xia, Y. Influence of

15

minerals and iron on natural gases generation during pyrolysis of type-III kerogen.

16

Marine and Petroleum Geology 2018, 89, 216−224.

17

(45) Lin, W.; Schimmelmann, A.; Mastalerz, M. Catalytic generation of methane at 60

18

to 100 °C and 0.1 to 300 MPa from source rocks containing kerogen Types I, II,

19

and III. Geochimica et Cosmochimica Acta 2018, 231, 88−116.

20

(46) Behar, F.; Vandenbroucke, M.; Tang, Y.; Marquis, F.; Espitalie, J. Thermal

21

cracking of kerogen in open and closed systems: determination of kinetic

22

parameters and stoichiometric coefficients for oil and gas generation. Organic 20


Page 20 of 33

Page 21 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1 2 3 4 5

Geochemistry 1997, 26, 321−339. (47) Hunt, J.M. Generetion and migration of light hydrocarbons. Science 1984, 226(4580), 1265−1270. (48) Tissot, B.P.; Welte, D.H. Petroleum Formation and Occurrence, second ed. Springer−Verlag, Berlin, Heidelberg, New York, Tokyo, 1984, pp. 74−266.

6

(49) Tang, Y.; Perry, J.K.; Jenden, P.D.; Schoell, M. Mathematical modeling of stable

7

carbon isotope ratios in natural gases. Geochimica et Cosmochimica Acta 2000,

8

64(15), 2673−2687.

9

(50) Zhang, S.; Mi, J.; He, K. Synthesis of hydrocarbon gases from four different carbon

10

sources and hydrogen gas using a gold-tube system by Fischer-Tropsch method.

11

Chemical Geology 2013, 349−350, 27−35.

12

(51) He, K.; Zhang. S.; Mi, J.; Zhang, W. The evolution of chemical groups and isotopic

13

fractionation at differentmaturation stages during lignite pyrolysis. Fuel 2018, 211,

14

492−506.

15 16 17 18

(52) Krupp, R. Physicochemical aspects of mercury metallogenesis. Chemical Geology 1988, 69(3), 345−356. (53) Paul, J.C.; Steinbach, P.B.; Owbny, D.R. Distribution of mercury in a Gulf Coast Lignite Mine. Energy & Fuels 2008, 22, 3950−3954.

19

(54) Smith, C.N.; Kesler, S.E.; Blum, J.D.; Rytuba, J.J. Isotope geochemistry of

20

mercury in source rocks, mineral deposits and spring deposits of the California

21

Coast Ranges. Earth and Planetary Science Letters 2008, 269, 399−407.

22

(55) Benoit, J.M.; Mason, R.P.; Gilmour, C.C.; Aiken, G.R. Constants for mercury 21


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

binding by dissolved organic matter isolates from the Florida Everglades.

2

Geochimica et Cosmochimica Acta 2001, 65(24), 4445−4451.

3

(56) Devai, I.; Delaune, R.D.; WHP, Jr.; Gambrell, R.P. Changes in methylmercury

4

concentration during storage: effect of temperature. Organic Geochemistry 2001,

5

32, 755−758.

6

(57) Hines, M.E.; Faganeli, J.; Adatto, I.; Horvas, M. Microbial mercury

7

transformations in marine, estuarine and freshwater sediment downstream of the

8

Idrija Mercury Mine, Slovenua. Applied Geochemistry 2006, 21, 1924−1939.

9

(58) Sanei, H.; Goodarzi, F. Relationship between organic matter and mercury in recent

10

lake sediment: The physical-geochemical aspects. Applied Geochemistry 2006, 21,

11

1900−1912.

12

(59) Balen, R.T.V.; Bergen, F.V.; Leeuw, C.D.; Pagnier, H.; Simmelink, H.; Wees,

13

J.D.V.; Verweij, J.M. Modelling the hydrocarbon generation and migration in the

14

west Netherlands Basin, the Netherlands. Netherlands Journal of Geosciences 2000,

15

79(1), 29−44.

16

(60) Huang, X.; Zheng, L.; Zhang, Q.; Chu, H.; Chu, H.; Yan, X.; Han, Y. Distribution

17

and modes of occurrence of mercury in coal seams altered by magmatic

18

hydrothermal from Wolonghu Coal Mine. Geological Journal of China

19

Universities 2015, 17(4), 559−565 (in Chinese with English abstract).

20

(61) Tang, S.; Feng, C.; Feng, X.; Zhu, J.; Sun, R.; Fan, H.; Wang, K.; Li, R.; Mao, T,;

21

Zhou, T. Stable isotope composition of mercury forms in flue gases from a typical

22

coal-fired power plant, Inner Mongolia, northern China. Journal of Hazardous 22


Page 22 of 33

Page 23 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1

Materials 2017, 328, 90−97.

2

(62) Chen, J.; Wang, W.; Zhu, Y. Affecting factors of Hg contents in gases in

3

petroliferous basin. Oil & Gas Geology 2001, 22(4), 352−354 (in Chinese with

4

English abstract).

5 6

(63) Liu, Q. Mercury concentration in natural gas and its distribution in the Tarim Basin. Science China: Earth Science 2013, 56, 1371−1379.

23


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1

Page 24 of 33

Table 1. Geochemical parameters of coal sample. RO (%)

TOC (%)

Tmax (ºC)

S1 (mg/g)

S2 (mg/g)

0.55

58.3

424

0.66

97.18

Maceral group (%) Exinite

Vitrinite

Sapropelinite

Inertinite

5

85

0

10

24


Page 25 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

Energy & Fuels

1 2

Table 2. Main geochemical parameters obtained by thermal simulation experiment on humic kerogen.

Sample weight (g)

3 4

Gas component (%)

Temperature

Dryness

δ13C (VPDB, ‰)

δD (‰, VSMOW)

Mercury

Liquid

Mercury yield

mercury (g)

10−3(g/g)

/

0.1015

2.0107

−299

467.6

0.0253

0.8453

−35.7

−288

1575.3

0.1018

3.4839

0.716

−36.0

−284

888.4

/

/

31.61

0.752

−31.2

−274

2776.3

/

/

0.47

31.62

0.796

−30.6

−257

1634.0

/

/

2.89

0.95

15.83

0.913

−28.0

−229

2149.3

0.1570

5.1324

1.58

3.17

0.84

23.16

0.914

−26.4

−193

372.5

0.2242

7.4312

0.09

3.40

2.99

0.87

17.51

0.922

−26.5

−165

2741.2

0.0933

3.1235

0.05

0.08

2.30

2.49

0.88

14.32

0.952

−26.4

−147

2044.4

0.0083

0.3102

0.02

0.09

1.37

2.93

0.90

11.12

0.963

−26.2

−136

557.9

/

/

0.00

0.03

1.11

2.64

0.75

4.71

0.994

−24.1

−134

1316.4

/

/

(ºC)

CO2

coefficient

CH4

C2H6

C3H8

C4H10

C5H12

C6+

N2

H2

CO

CH4

CH4

50.48

320

10.65

3.87

2.16

0.82

0.23

0.08

6.40

n.d.

0.90

74.90

0.601

−33.0

−300

29.93

340

17.54

7.04

3.31

1.10

0.33

0.18

2.47

n.d.

1.00

67.03

0.598

−34.8

29.22

360

25.89

9.93

4.48

1.51

0.44

0.16

4.02

n.d.

0.70

52.87

0.613

50.15

380

31.01

8.26

2.92

0.89

0.25

0.16

2.02

7.14

1.14

46.19

40.5

400

47.87

10.78

3.52

1.13

0.34

0.14

1.43

2.67

0.51

34.69

420

50.64

8.34

3.16

1.18

0.31

0.11

1.28

2.89

30.59

440

70.48

4.79

1.32

0.45

0.15

0.08

3.07

30.17

460

65.07

4.38

1.23

0.36

0.13

0.08

29.87

480

69.30

4.53

1.06

0.18

0.06

26.76 20.4

500

76.09

3.11

0.54

0.14

525

80.51

2.87

0.15

0.05

19.6

550

90.24

0.43

0.07

0.01

Note: "/" indicates no data."n.d." means not detected.

25


content in gas ng /m3

Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1 2

Fig 1. Location map of sampling point.

26


Page 26 of 33

Page 27 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1 2

Fig 2. Organic maceral characteristics of coal sample from Shaping Mine, Ordos Basin, China.

27


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1 2

Fig 3. Schematic diagram of thermal-simulation experimental device.

28


Page 28 of 33

Page 29 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1 2

Fig 4. δ13C1 versus temperature (a), and δD1 versus temperature (b).

29


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1 2

Fig 5. Liquid mercury collected in thermal simulation experiment.

30


Page 30 of 33

Page 31 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

1 2

Fig 6. Yield of liquid mercury in thermal simulation experiment.

31


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1 2

Fig 7. Relationship between methane content and temperature in thermal simulation experiment.

32


Page 32 of 33

Page 33 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

3 4 5

Fig 8. Genetic model of mercury in gas reservoirs; (a) source-rock controlling type; (b) fault controlling type; and (c) source rock/fault joint controlling type

33


The first discovery and significance of liquid mercury in a thermal

Recommend Documents