Distribution and geochemical significance of phenylphenanthrenes and their isomers in selected oils and rock extracts from the Tarim Basin, NW China

Shao-Ying Huang,Bao-Shou Zhang,Rong-Hui Fang,T.-G Wang,Dao-Wei Wang,Zhong-Yao Xiao,Mei-Jun Li,Fu-Lin Yang,Ke Zhang,Qing Zhao

doi:10.1007/s12182-016-0095-4

Abstract

Twenty-two oil samples and eight source rock samples collected from the Tarim Basin, NW China were geochemically analyzed to investigate the occurrence and distribution of phenylphenanthrene (PhP), phenylanthracene (PhA), and binaphthyl (BiN) isomers and methylphenanthrene (MP) isomers in oils and rock extracts with different depositional environments. Phenylphenanthrenes are present in significant abundance in Mesozoic lacustrine mudstones and related oils. The relative concentrations of PhPs are quite low or below detection limit by routine gas chromatography–mass spectrometry (GC–MS) in Ordovician oils derived from marine carbonates. The ratio of 3-PhP/3-MP was used in this study to describe the relative abundance of phenylphenanthrenes to their alkylated counterparts—methylphenanthrenes. The Ordovician oils in the Tabei Uplift have quite low 3-PhP/3-MP ratios (<0.10), indicating their marine carbonate origin, associating with low Pr/Ph ratios (pristane/phytane), high ADBT/ADBF values (relative abundance of alkylated dibenzothiophenes to alkylated dibenzofurans), low C30 diahopane/C30 hopane ratios, and low Ts/(Ts + Tm) (18α-22, 29, 30-trisnorneohopane/(18α-22, 29, 30-trisnorneohopane + 17α-22, 29, 30-trisnorhopane)) values. In contrast, the oils from Mesozoic and Paleogene sandstone reservoirs and related Mesozoic lacustrine mudstones have relatively higher 3-PhP/3-MP ratios (>0.10), associating with high Pr/Ph, low ADBT/ADBF, high Ts/(Ts + Tm), and C30 diahopane/C30 hopane ratios. Therefore, the occurrence of significant amounts of phenylphenanthrenes in oils typically indicates that the organic matter of the source rocks was deposited in a suboxic environment with mudstone deposition. The phenylphenanthrenes may be effective molecular markers, indicating depositional environment and lithology of source rocks.

Highlights

Phenyl-substituted polycyclic aromatic hydrocarbons (PAHs) and their heterocyclic counterparts are important components in aromatic fractions of some crude oils and sedimentary rock extracts (Marynowski et al 2001, 2002, 2004; Rospondek et al 2007, 2009; Li et al 2012a; Grafka et al 2015)
Twenty-two oil samples and eight source rock samples collected from the Tarim Basin, NW China were geochemically analyzed to investigate the occurrence and distribution of phenylphenanthrene (PhP), phenylanthracene (PhA), and binaphthyl (BiN) isomers and methylphenanthrene (MP) isomers in oils and rock extracts with different depositional environments
The identification and elution order of all isomers of methylphenanthrenes (MPs), phenylphenanthrenes were determined by the comparison of their mass spectra and standard retention indices (IHP-5MS) with those reported in literature (Lee et al 1979; Rospondek et al 2009)

Summary

Introduction

Phenyl-substituted polycyclic aromatic hydrocarbons (PAHs) and their heterocyclic counterparts are important components in aromatic fractions of some crude oils and sedimentary rock extracts (Marynowski et al 2001, 2002, 2004; Rospondek et al 2007, 2009; Li et al 2012a; Grafka et al 2015). A series of phenylphenanthrene (PhP), phenylanthracene (PhA), and binaphthyl (BiN) isomers have been firmly identified by using authentic standards (Rospondek et al 2009). All PhP, PhA, and BiN isomers have been discovered in marine sedimentary rocks (Rospondek et al 2009; Grafka et al 2015), Tertiary and Jurassic lacustrine shales (Li et al 2012a) and tire fire products (Wang et al 2007).

Methods

Results

Conclusion