Phenyldibenzofurans and Methyldibenzofurans in Source Rocks and

---

Article pubs.acs.org/EF

Phenyldibenzofurans and Methyldibenzofurans in Source Rocks and Crude Oils, and Their Implications for Maturity and Depositional Environment Lu Yang,† Meijun Li,*,† T.-G. Wang,† Xiaoqiang Liu,‡ Weidong Jiang,‡ Ronghui Fang,† and Hongfei Lai† †

State Key Laboratory of Petroleum Resources and Engineering, College of Geosciences, China University of Petroleum, Beijing 102249, PR China ‡ College of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, Sichuan 643000, PR China ABSTRACT: The distribution of phenyldibenzofurans (PhDBFs) and methyldibenzofurans (MDBFs) and their potential implications in petroleum organic geochemistry have been investigated for sediment extracts and crude oils derived from lacustrine shale, marine shale, marine carbonate, and terrestrial (fluvial/deltaic/fresh water) mudstone. PhDBF isomers in a set of lacustrine shales from the Liaohe Basin (East China) are identified in the m/z 244 mass chromatograms of the aromatic fraction by coinjection of internal synthetic standards on a high resolution capillary column (HP-5MS). The results show that the relative abundance of 4-PhDBF/2-PhDBF and 4-PhDBF/(2-PhDBF+3-PhDBF) increase gradually with increasing burial depth and maturity (R0 ≥ 0.6%), and have a good correlation with vitrinite reflectance in lacustrine shales from wells S202 and SG1 in the Liaohe Basin. These two ratios, defined as phenyldibenzofuran ratio-1 and -2 (PhFR-1 and PhFR-2), may be potential maturity indicators for mature sediments in this study. Four MDBF isomers are also ubiquitously present in all samples studied, and show regular distribution patterns in the m/z 182 mass chromatograms of the aromatic fraction. In rocks and oils derived from the terrestrial depositional environments of the Liaohe and Beibuwan Basins (China), there is a marked predominance of 2- and 3MDBF over 4- and 1-MDBF, and three peaks formed by 4-, 2-+3-, and 1-MDBF show a reversed “V-shaped” distribution pattern in the m/z 244 mass chromatograms. However, for samples derived from the marine environment in the Termit (Africa) and Tarim (China) Basins, the abundances of 4-MDBF generally exceed or approach those of 2- and 3-MDBF. A cross-plot of (1+4)-/(2+3)-MDBF versus Pr/Ph ratios measured on rocks and oils from various depositional environments is used here to investigate the effect of the depositional environment and lithology on the distribution patterns of four MDBF isomers. This cross-plot classified the samples in this study into the following five environmental/lithological zones: marine carbonate; marine carbonate and shale; marine shale; lacustrine shale; and fluvial/deltaic/fresh water lacustrine shales. Samples from various depositional environments in this study can be basically distinguished.

1. INTRODUCTION

The phenyl derivatives of DBF have also been identified in marine sedimentary rocks and hydrothermal petroleum,5 while there is still no report on their occurrence in oils and related source rocks of lacustrine origin. Diagenetic/catagenetic oxidation of sedimentary organic matter at the redox interface in buried sedimentary rocks and the oxidizing pyrolysis of coal and coal-derived materials are major sources of phenylsubstituted polycyclic aromatic hydrocarbons (PAHs).5,21,22 Based on ionic versus free-radical phenylation comparative experiments, it was suggested that these compounds must have been formed by free-radical PAH phenylation reactions.22 PhDBFs and phenyldibenzothiophenes (PhDBTs) usually occur together in sedimentary rocks, and these two groups of compounds are believed to form under similar conditions.5 It has been documented that the distribution of PhDBTs is controlled primarily by the organic matter maturity.5 However, the geochemical applications of oxygen−heterocyclic aromatic compounds are far less than that of their sulfur counterparts.13−20

Dibenzofuran (DBF), methyldibenzofuran (MDBF), and phenyldibenzofuran (PhDBF) are important oxygen−heterocyclic aromatic compounds (Figure 1), which are usually detected in the aromatic fraction of coal, sedimentary rocks, combustion products of municipal solid waste, and crude oils.1−7 DBF and four MDBF isomers have been identified by gas chromatography or gas chromatography−mass spectrometry (GC-MS) analyses of the aromatic fraction of sedimentary rocks and crude oils.4,7 The origin of dibenzofuran and its alkylated homologues (collectively abbreviated as DBFs) has been reported in much literature. Their possible precursors include polysaccharides, phenols, lichen, lignin of woody plants, and biphenyls.4,8−12 DBFs have also been empirically used to indicate crude oil source rock depositional environments and lithologies, such as the cross-plot of alkyldibenzothiophene/ alkyldibenzofuran ratio (ADBT/ADBF) versus pristane/ phytane (Pr/Ph) ratio.4 However, the application of these compounds in organic geochemistry has received less attention than that given to their sulfur-containing counterparts dibenzothiophenes.13−20 © XXXX American Chemical Society

Received: October 26, 2016 Revised: December 22, 2016 Published: February 7, 2017 A

DOI: 10.1021/acs.energyfuels.6b02801 Energy Fuels XXXX, XXX, XXX−XXX

Article

Energy & Fuels

Liaohe Basin is located in the Liaoning Province, adjacent to the Bohai Bay. It is a rift basin with a Cenozoic depositional thickness of more than 3000−4000 m.25,26 A total of 46 lacustrine shales were collected from the Eocene−Oligocene Shahejie and Dongying formations of two boreholes (wells S202 and SG1). The selected oils mainly occur in the Eocene Shahejie Formation. The geological background for the Western Depression has been summarized in previous publications.15−17,27,28 The bulk properties, including total organic carbon (TOC) content, Rock-Eval parameters, type of organic matter, and vitrinite reflectance, were reported by Li et al.15−17,27,28 Part of the data are also shown in Table 1. These rock samples are typical lacustrine shales containing Type II/III kerogen. All oil samples originated from source rocks deposited in typical lacustrine shales.15−17 The Termit Basin is one of the largest Cretaceous−Tertiary rift basins in the West and Central Africa rift system, which contains an estimated maximum sediment thickness of around 12000 m.29 These sedimentary rocks comprise 800−4200 m of the Upper Cretaceous shallow marine shales.29 Here, a total of 24 marine shales were collected from the Upper Cretaceous Yogou and Donga formations. There are two main oil families in the West and Central Africa rift system. One type is of lacustrine origin, and the second is of marine origin.30 Marine shale extracts have relatively higher concentrations of homohopanes and a homologues series of tricyclics/tetracyclics, and gammacerane.30 A total of 18 oils collected from the Termit Basin originated from the Upper Cretaceous Yogou Formation marine shales, and are characterized by relatively low Pr/Ph, high gammacerane/C30 hopane ratios and low relative abundance of diahopanes.31 The Halahatang Depression is located in the center of the Tabei Uplift, which is one of the major prolific oil-producing regions in the Tarim Basin. The majority of oil accumulations mainly occur in the Middle and Upper Ordovician carbonate rocks in the Tabei Uplift. Based on various organic geochemical parameters, two petroleum families can be classified in the Tabei Uplift.19,32−35 Oil samples selected from the Ordovician reservoir in the Halahatang Oilfield are considered to derive from the Middle-Upper Ordovician marine carbonates.19,32−35 The Fushan Depression, situated in the south of the Qiongzhou Strait, north of Hainan Island, is a Mesozoic− Cenozoic rifting half-graben.36,37 The majority of the oils were discovered mainly in the sandstone reservoir of the third member of the Eocene Liushagang Formation.36,37 Oil accumulation is dominated by light oils or condensates.33,34 The geological settings for the Fushan Depression have been summarized in numerous references.13,17,19,31,36,37 Crude oils discovered in the sandstone reservoir of the third member of the Eocene Liushagang Formation in the Fushan Depression are considered to be typical terrestrial-sourced high-mature oils.13,17,19,31,34,35 Here, all of the oil samples collected from the Fushan Depression represent oils originated from source rocks deposited in a typical terrestrial fluvial/deltaic/fresh water lacustrine environment.

Figure 1. Structures of methyldibenzofuran and phenyldibenzofuran discussed in the text.

This paper reports the occurrence and distribution of MDBFs and PhDBFs in rock extracts or oils derived from lacustrine shale, marine shale, marine carbonate, and terrestrial fluvial/deltaic/fresh water lacustrine shales. Especially, PhDBF isomers in a set of lacustrine shales are identified by coinjection of internal standards on a high resolute capillary column (HP5MS). The retention indices for PhDBF isomers in source rocks and crude oils were also calculated based on the equation given by Lee et al.23,24 Some maturity indicators based on the relative abundance of these isomers were preliminarily proposed. This paper studies the possibility of using MDBF isomers as indicators for identifying depositional environment and lithology on the basis of the distribution patterns of these compounds in geological samples derived from various depositional environments. The results can expand the understanding of the occurrence and application for alkyland phenyl-substituted dibenzofurans in sedimentary organic matter and crude oils with various organic facies.

2. SAMPLES AND GEOLOGICAL SETTINGS A total of 46 lacustrine shales and 15 related oils from the Western Depression of the Liaohe Basin (East China), and 25 marine shales and 18 related oils from the Termit Basin (Eastern Niger) were collected. Other samples provided for this study consist of 27 Ordovician marine carbonate oils from the Halahatang Oilfield in the Tarim Basin (Northwest China), and 26 Cenozoic fluvial/deltaic/fresh water lacustrine oils from the Fushan Depression, Beibuwan Basin (South China Sea).

3. MATERIALS AND METHODS 3.1. Standards. Three phenyldibenzofuran isomers (1-PhDBF, 2PhDBF, and 4-PhDBF) were purchased from Chiron Scientific, Inc. (Trondheim, Norway). Phenanthrene and chrysene (Accustandard Inc., New Haven, USA) were added to the solutions of authentic standards as PAH markers, and we were therefore able to calculate the standard retention indices for each compound in the GC-MS analysis. B

DOI: 10.1021/acs.energyfuels.6b02801 Energy Fuels XXXX, XXX, XXX−XXX

Article

Energy & Fuels

Table 1. Total Organic Carbon Content, Selected Parameters of Rock-Eval Pyrolysis, Fraction of Extractable Organic Matter (EOM), and Selected Geochemical Parameters for the Eocene Samples from Well S202 and Well SG1a Sample No.

Depth (m)

TOC (%)

Tmax (°C)

S202-2 S202-3 S202-4 S202-5 S202-7 S202-9 S202-10 S202-12 S202-14 S202-15 S202-16 S202-17 S202-18 S202-20 S202-21 S202-22 S202-23 S202-24 S202-26 S202-29 S202-30 S202-31 S202-32 S202-33 SG04 SG05 SG06 SG07 SG08 SG09 SG11 SG12 SG13 SG14 SG15 SG16 SG17 SG18 SG19 SG20 SG21 SG22

2609 2691 2808 2826 2897 3208 3235 3489 3518 3633 3688 3760 3813 3913 3947 4030 4062 4175 4254 4406 4456 4548 4564 4644 2314 2352 2404 2459 2485 2518 2653 2672 2730 2783 2815 2888 2914 2956 3111 3239 3306 3372

0.77 0.83 1.52 1.53 1.22 1.26 1.38

437 435 437 438 436 438 441

1.69 1.50 1.89 1.41 1.23 1.28 1.26 1.35 1.34 1.73 1.46 1.22 1.20 1.13 1.50 2.11 1.37 1.44 1.72 1.93 2.24 2.11 1.83 1.92 1.91 1.86 1.90 1.76 1.78 1.77 2.13 1.99 3.27 1.87

441 441 444 445 446 445 446 447 446 449 450 449 465 469 462 460 432 435 433 431 430 430 433 434 434 435 434 435 437 437 437 437 435 439

RO% mean

0.58 0.58 0.59 0.63 0.64 0.65 0.69 0.69 0.71

0.77 0.98 1.09 1.35 1.36 1.43 0.36 0.36 0.33 0.32 0.33 0.33 0.34 0.44 0.45 0.52 0.47 0.49 0.44 0.61 0.61 0.58 0.59

HI (mg/g)

EMO (mg/g Corg)

MPI-1

MDR

PhFR-1

PhFR-2

4-/(2+3)-MDBF

140 90 199 216 133 144 136

69.56 33.08 33.44 93.65 35.66 57.16 154.22

203 168 168 178 146 180 149 158 157 94 114 92 49 40 43 38 172 164 235 329 356 409 296 391 359 354 336 354 312 298 345 319 274 294

117.85 148.55 27.83 622.07 147.52 148.82 187.94 137.18 192.73 46.01 128.99 112.70 73.23 842.65 41.65 22.63 55.11 40.80 25.72 59.38 42.99 45.97 41.51 61.70 66.43 60.89 66.73 74.46 62.46 67.38 84.32 138.26 203.93 170.68

0.43 0.50 0.20 0.19 0.52 0.72 0.69 0.85 0.51 0.64 0.63 0.65 0.67 0.73 0.74 0.74 1.10 1.28 1.01 1.22 1.72 1.84 1.93 2.51 0.28 0.33 0.29 0.35 0.41 0.32 0.33 0.67 0.79 0.61 0.66 0.77 0.69 0.73 0.79 0.45 0.39 0.48

2.46 2.60 3.07 3.71 4.83 1.87 1.34 1.67 4.24 6.32 6.09 7.93 7.14 6.51 7.09 11.57 13.30 15.86 12.56 14.15 18.74 15.05 22.16 27.65 1.76 1.68 1.73 1.24 1.28 1.59 1.85 1.99 2.69 2.14 2.56 2.61 2.64 2.26 2.43 2.88 2.89 2.99

0.88 0.87 0.77 0.78 0.64 0.71 0.75 0.99 0.99 2.13 2.36 2.33 2.10 2.29 2.31 3.67 6.74 11.07 7.77 14.01 29.27 17.39 23.44 32.14 0.87 1.01 0.93 0.76 0.77 0.75 1.09 1.28 1.43 2.79 1.37 1.58 1.61 1.28 1.42 0.91 0.89 0.85

0.52 0.53 0.48 0.47 0.44 0.46 0.49 0.61 0.63 1.24 1.46 1.34 1.22 1.32 1.35 1.96 3.84 6.53 4.25 7.09 14.07 9.89 11.51 17.23 0.53 0.62 0.56 0.48 0.49 0.48 0.65 0.82 0.86 1.51 0.84 0.94 0.95 0.79 0.82 0.55 0.54 0.51

0.43 0.35 0.32 0.37 0.37 0.57 0.36 0.32 0.41 0.56 0.53 0.51 0.54 0.69 0.61 0.72 0.66 0.83 0.75 0.71 0.68 0.64 0.66 0.56 0.45 0.59 0.54 0.54 0.54 0.57 0.62 0.60 0.69 0.59 0.57 0.66 0.53 0.50 0.55 0.52 0.51 0.50

a Note: EMO: extractable organic matter; MPI-1: 1.5×(3+2)-methylphenanthrene/{phenanthrene + (9+1)-methylphenanthrene}; MDR: 4-/1methyldibenzothiophene; PhFR-1: 4-/2-phenyldibenzofuran; PhFR-2: 4-/(2+3)-phenyldibenzofuran.

300 °C. The MS was run by electron impact ionization at 70 eV, in full-scan mode with a scanning range of 50−600 Da.

3.2. Extraction and Analysis. Rock samples were ground into powder ( 3 (Figure 9). We can see that samples derived from various depositional environments are basically distinguished (Figure I

DOI: 10.1021/acs.energyfuels.6b02801 Energy Fuels XXXX, XXX, XXX−XXX

Article

Energy & Fuels

■

(21) Rospondek, M. J.; Marynowski, L.; Góra, M. Novel arylated polyaromatic thiophenes: Phenylnaphtho[b]thiophenes and naphthylbenzo[b]thiophenes as markers of organic matter diagenesis buffered by oxidising solutions. Org. Geochem. 2007, 38, 1729−1756. (22) Rospondek, M. J.; Marynowski, L.; Chachaj, A.; Góra, M. Novel aryl polycyclic aromatic hydrocarbons: Phenylphenanthrene and phenylanthracene identification, occurrence and distribution in sedimentary rocks. Org. Geochem. 2009, 40, 986−1004. (23) Lee, M. L.; Vassilaros, D. L.; White, C. M. Retention indices for programmed-temperature capillary-column gas chromatography of polycyclic aromatic hydrocarbons. Anal. Chem. 1979, 51, 768−773. (24) Vassilaros, D. L.; Kong, R. C.; Later, D. W.; Lee, M. L. Linear retention index system for polycyclic aromatic compounds: Critical evaluation and additional indices. J. Chromatogr. A 1982, 252, 1−20. (25) Hu, L.; Fuhrmann, A.; Poelchau, H. S.; Horsfield, B.; Zhang, Z.; Wu, T.; Chen, Y.; Li, J. Numerical simulation of petroleum generation and migration in the Qingshui sag, western depression of the Liaohe basin, northeast China. AAPG Bull. 2005, 89, 1629−1649. (26) Huang, H.; Pearson, M. J. Source rock palaeoenvironments and controls on the distribution of dibenzothiophenes in lacustrine crude oils, Bohai Bay Basin, eastern China. Org. Geochem. 1999, 30, 1455− 1470. (27) Li, M.; Shi, S.; Wang, T.-G.; Zhong, N.; Wang, G.; Cui, J. The occurrence and distribution of phenylphenanthrenes, phenylanthracenes and binaphthyls in Palaeozoic to Cenozoic shales from China. Appl. Geochem. 2012, 27, 2560−2569. (28) Li, M.; Wang, H.; Shi, S.; Fang, R.; Tang, Q.; Wang, D. The occurrence and distribution of phenylnaphthalenes, terphenyls and quaterphenyls in selected lacustrine shales and related oils in China. Org. Geochem. 2016, 95, 55−70. (29) Wan, L.; Liu, J.; Mao, F.; Lv, M.; Liu, B. The petroleum geochemistry of the Termit Basin, Eastern Niger. Mar. Pet. Geol. 2014, 51, 167−183. (30) Genik, G. J. Petroleum geology of rift basins in Niger, Chad, and Central African Republic. AAPG Bull. 1993, 75, 1405−1434. (31) Li, M.; Wang, T.-G.; Zhong, N.; Zhang, W.; Sadik, A.; Li, H. Ternary diagram of fluorenes, dibenzothiophenes and dibenzofurans: Indicating depositional environment of crude oil source rocks. Energy Explor. Exploit. 2013, 31, 569−588. (32) Li, M.; Wang, T.-G.; Lillis, P. G.; Wang, C.; Shi, S. The significance of 24-norcholestanes, triaromatic steroids and dinosteroids in oils and Cambrian−Ordovician source rocks from the cratonic region of the Tarim Basin, NW China. Appl. Geochem. 2012, 27, 1643−1654. (33) Huang, S.; Li, M.; Zhang, K.; Wang, T.-G.; Xiao, Z.; Fang, R.; Zhang, B.; Wang, D.; Zhao, Q.; Yang, F. Distribution and geochemical significance of phenylphenanthrenes and their isomers in selected oils and rock extracts from the Tarim Basin, NW China. Pet. Sci. 2016, 13, 183−191. (34) Xiao, Z.; Li, M.; Huang, S.; Wang, T.-G.; Zhang, B.; Fang, R.; Zhang, K.; Ni, Z.; Zhao, Q.; Wang, D. Source, oil charging history and filling pathways of the Ordovician carbonate reservoir in the Halahatang Oilfield, Tarim Basin, NW China. Mar. Pet. Geol. 2016, 73, 59−71. (35) Yang, L.; Zhang, C.; Li, M.; Zhao, J.; Qi, X.; Du, J. The effect of slight to minor biodegradation on C6 to C7 light hydrocarbons in crude oils: a case study from Dawanqi Oilfield in the Tarim Basin, NW China. Acta Geochim. 2016, 35, 203−214. (36) Li, M.; Wang, T.-G.; Liu, J.; Lu, H.; Wu, W.; Gao, L. Occurrence and origin of carbon dioxide in the Fushan Depression, Beibuwan Basin, South China Sea. Mar. Pet. Geol. 2008, 25, 500−513. (37) Li, M.; Wang, T.-G.; Liu, J.; Zhang, M.; Lu, H.; Ma, Q.; Gao, L. Biomarker 17α (H)- diahopane: A geochemical tool to study the petroleum system of a Tertiary lacustrine basin, Northern South China Sea. Appl. Geochem. 2009, 24, 172−183. (38) Meyer zu Reckendorf, R. Identification of phenyl-substituted polycyclic aromatic compounds in ring furnace gases using GC-MS and GC-AED. Chromatographia 1996, 45, 173−182.

REFERENCES

(1) Hayatsu, R.; Winans, R. E.; Scott, R. G.; Moore, L. P.; Studier, M. H. Trapped organic compounds and aromatic units in coals. Fuel 1978, 57, 541−548. (2) Fan, P.; Philp, R. P.; Li, Z.; Ying, G. Geochemical characteristics of aromatic hydrocarbons of crude oils and source rocks from different sedimentary environments. Org. Geochem. 1990, 16, 427−435. (3) Fan, P.; Philp, R. P.; Li, Z.; Yu, X.; Ying, G. Biomarker distributions in crude oils and source rocks from different sedimentary environments. Chem. Geol. 1991, 93, 61−78. (4) Radke, M.; Vriend, S. P.; Ramanampisoa, L. R. Alkyldibenzofurans in terrestrial rocks: influence of organic facies and maturation. Geochim. Cosmochim. Acta 2000, 64, 275−286. (5) Marynowski, L.; Rospondek, M. J.; Reckendorf, R. M. Z.; Simoneit, B. R. T. Phenyldibenzofurans and phenyldibenzothiophenes in marine sedimentary rocks and hydrothermal petroleum. Org. Geochem. 2002, 33, 701−714. (6) Hajizadeh, Y.; Onwudili, J. A.; Williams, P. T. PCDD/F formation from oxy-PAH precursors in waste incinerator flyash. Chemosphere 2011, 85, 1672−1681. (7) Li, M.; Ellis, G. Qualitative and quantitative analysis of dibenzofuran, alkyldibenzofurans, and benzo[b]naphthofurans in crude oils and source rock extracts. Energy Fuels 2015, 29, 1421−1430. (8) Sephton, M. A.; Looy, C. V.; Veefkind, R. J.; Visscher, H.; Brinkhuis, H.; de Leeuw, J. W. Cyclic diaryl ethers in a Late Permian sediment. Org. Geochem. 1999, 30, 267−273. (9) Pastorova, R. E.; Botto, A. P. W.; Boon, J. J. Cellulose char structure: a combined analytical Py−GC−MS, FTIR, and NMR study. Carbohydr. Res. 1994, 262, 27−47. (10) Born, J. G. P.; Louw, R.; Mulder, P. Formation of dibenzodioxins and dibenzofurans in homogenous gas-phase reactions of phenols. Chemosphere 1989, 19, 401−406. (11) Fenton, S.; Grice, K.; Twitchett, R. J.; Böttcher, M. E.; Looy, C. V.; Nabbefeld, B. Changes in biomarker abundances and sulfur isotopes of pyrite across the Permian−Triassic (P/Tr) Schuchert Dal section (East Greenland). Earth Planet. Sci. Lett. 2007, 262, 230−239. (12) Asif, M. Geochemical applications of polycyclic aromatic hydrocarbons in crude oils and sediments from Pakistan. Ph.D. thesis, University of Engineering and Technology, Lahore, Pakistan, 2010. (13) Li, M.; Wang, T.-G.; Liu, J.; Zhang, M.; Lu, H.; Ma, Q.; Gao, L. Total alkyl dibenzothiophenes content tracing the filling pathway of condensate reservoir in the Fushan depression, South China Sea. Sci. China, Ser. D: Earth Sci. 2008, 51, 138−145. (14) Li, M.; Wang, T.-G.; Simoneit, B. R. T.; Shi, S.; Zhang, L.; Yang, F. Qualitative and quantitative analysis of dibenzothiophene, its methylated homologues, and benzonaphthothiophenes in crude oils, coal, and sediment extracts. J. Chromatogr. A 2012, 1233, 126−136. (15) Li, M.; Zhong, N.; Shi, S.; Zhu, L.; Tang, Y. The origin of trimethyldibenzothiophenes and their application as maturity indicators in sediments from the Liaohe Basin, East China. Fuel 2013, 103, 299−307. (16) Li, M.; Simoneit, B. R. T.; Zhong, N.; Fang, R. The distribution and origin of dimethyldibenzothiophenes in sediment extracts from the Liaohe Basin, East China. Org. Geochem. 2013, 65, 63−73. (17) Li, M.; Wang, T.-G.; Shi, S.; Liu, K.; Ellis, G. Benzo[b]naphthothiophenes and alkyl dibenzothiophenes: Molecular tracers for oil migration distances. Mar. Pet. Geol. 2014, 57, 403−417. (18) Li, M.; Wang, T.-G.; Shi, S.; Zhu, L.; Fang, R. H. Oil maturity assessment using maturity indicators based on methylated dibenzothiophenes. Pet. Sci. 2014, 11, 234−246. (19) Fang, R.; Wang, T.-G.; Li, M.; Xiao, Z.; Zhang, B.; Huang, S.; Shi, S.; Wang, D.; Deng, W. Dibenzothiophenes and benzonaphthothiophenes: Molecular markers for tracing oil filling pathways in the carbonate reservoir of the Tarim Basin, NW China. Org. Geochem. 2016, 91, 68−80. (20) Yang, L.; Li, M.; Wang, T.-G.; Shi, Y. Dibenzothiophenes and benzonaphthothiophenes in oils, and their application in identifying oil filling pathways in Eocene lacustrine clastic reservoirs in the Beibuwan Basin, South China Sea. J. Pet. Sci. Eng. 2016, 146, 1026−1036. J

DOI: 10.1021/acs.energyfuels.6b02801 Energy Fuels XXXX, XXX, XXX−XXX

Article

Energy & Fuels (39) Liu, X.; He, X.; Qiu, N.; Yang, X.; Tian, Z.; Li, M.; Xue, Y. Molecular simulation of CH4, CO2, H2O and N2 molecules adsorption on heterogeneous surface models of coal. Appl. Surf. Sci. 2016, 389, 894−905. (40) Radke, M.; Welte, D. H.; Willsch, H. Maturity parameters based on aromatic hydrocarbons: Influence of the organic matter type. Org. Geochem. 1986, 10, 51−63. (41) Radke, M. Organic geochemistry of aromatic hydrocarbons. Adv. Petrol. Geochem. 1987, 2, 141−207. (42) Radke, M.; Welte, D. The methylphenanthrene index (MPI): a maturity parameter based on aromatic hydrocarbons. 1983. In Bjorøy, M. Ed.; Adv. Org. Geochem.; Wiley: New York, 1981; pp 504−512. (43) Meyer zu Reckendorf, R. Phenyl-substituted polycyclic aromatic compounds as intermediate products during pyrolytic reactions involving coal tars, pitches and related materials. Chromatographia 2000, 52, 67−76.

K

DOI: 10.1021/acs.energyfuels.6b02801 Energy Fuels XXXX, XXX, XXX−XXX