A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dim...A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GCTOFMS).By analyzing the distribution characteristics of C0-C5alkylbenzenes,it is found that the content of some alkylbenzenes varies greatly in crude oils.Based on the distribution characteristics of 1,2,4,5-tetramethylbenzene(Te MB)and 1,2,3,4-Te MB,the ratio of 1,2,4,5-Te MB to 1,2,3,4-Te MB is proposed to indicate the organic matter origin and depositional environment of ancient sediments.Oil samples originated mainly from lower hydrobiont,algae,bacteria and source rocks deposited under reducing/anoxic conditions have low 1,2,4,5-/1,2,3,4-Te MB values(less than 0.6),while oil samples originated mainly from terrestrial higher plants and source rocks deposited under oxic/sub-oxic conditions have higher 1,2,4,5-/1,2,3,4-Te MB values(greater than 1.0).The significant difference of 1,2,4,5-/1,2,3,4-Te MB values is controlled by 1,2,4,5-Te MB content.1,2,4,5-Te MB content in oils derived from source rocks deposited in oxidized sedimentary environment(greater than 1.0 mg/g whole oil)is higher than that in oils from source rocks deposited in reduced sedimentary environment(less than 1.0 mg/g whole oil).1,2,4,5-/1,2,3,4-Te MB ratio might not or slightly be affected by evaporative fractionation,biodegradation and thermal maturity.1,2,4,5-/1,2,3,4-Te MB ratio and 1,2,4,5-Te MB content can be used as supplementary parameter for the identification of sedimentary environment and organic matter input.It should be noted that compared to the identification of organic matter sources,the 1,2,4,5-/1,2,3,4-Te MB parameter is more effective in identifying sedimentary environments.展开更多
With comprehensive two-dimensional gas chromatography linked to time-of-flight mass spectrometry(GC × GC-TOFMS),ten light hydrocarbon(LH) compounds were qualitatively and quantitatively studied in light hydrocarb...With comprehensive two-dimensional gas chromatography linked to time-of-flight mass spectrometry(GC × GC-TOFMS),ten light hydrocarbon(LH) compounds were qualitatively and quantitatively studied in light hydrocarbons(LHs) components of crude oils.For significant differences in the concentrations of 3-isoproyltoluene(3-iPT),4-isoproyltoluene(4-iPT) and 2-isoproyltoluene(2-iPT) in crude oils,and the 2-iPT probably derived mainly from similar skeleton monocyclic terpenoids via dehydrogenation and aromatization,the ratios of(3+4)-/2-iPT(iPTr),3-/2-iPT(iPTr1) and 4-/2-iPT(iPTr2) are proposed to distinguish the organic matter origin of crude oils.Relatively higher iPTr(>8.0),iPTr1(>7.0) and iPTr2(>4.0) values indicate that crude oils are sourced from the co-contribution of lower aquatic organisms,bacteria,algae,and terrestrial higher plants,whereas lower iPTr(<5.0),iPTr1(<3.0),iPTr2(<2.0) values suggest that crude oils originated from terrestrial higher plants.The iPTr,iPTr1,and iPTr2 values show notable distinction which is mainly controlled by 2-iPT concentrations,while the concentrations of 3-iPT and 4-iPT have similar distribution range in all studied oils.The 2-iPT depleted in marine oils from the Tarim Basin and lacustrine oils from the Beibuwan Basin is less than 0.30 mg/g LHs,whereas 2-iPT enriched in swamp oils from the Tarim Basin is greater than 0.50 mg/g LHs.The iPTr,iPTr1,and iPTr2 ratios and 2-iPT concentrations can be used to distinguish the organic matter origin of crude oils,especially for light oils and condensates with low concentrations of biomarkers.展开更多
基金supported by Doctor’s Scientific Research Initiation Project of Yan’an University(YAU202213093)National Natural Science Foundation of China(Grant No.41503029)。
文摘A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GCTOFMS).By analyzing the distribution characteristics of C0-C5alkylbenzenes,it is found that the content of some alkylbenzenes varies greatly in crude oils.Based on the distribution characteristics of 1,2,4,5-tetramethylbenzene(Te MB)and 1,2,3,4-Te MB,the ratio of 1,2,4,5-Te MB to 1,2,3,4-Te MB is proposed to indicate the organic matter origin and depositional environment of ancient sediments.Oil samples originated mainly from lower hydrobiont,algae,bacteria and source rocks deposited under reducing/anoxic conditions have low 1,2,4,5-/1,2,3,4-Te MB values(less than 0.6),while oil samples originated mainly from terrestrial higher plants and source rocks deposited under oxic/sub-oxic conditions have higher 1,2,4,5-/1,2,3,4-Te MB values(greater than 1.0).The significant difference of 1,2,4,5-/1,2,3,4-Te MB values is controlled by 1,2,4,5-Te MB content.1,2,4,5-Te MB content in oils derived from source rocks deposited in oxidized sedimentary environment(greater than 1.0 mg/g whole oil)is higher than that in oils from source rocks deposited in reduced sedimentary environment(less than 1.0 mg/g whole oil).1,2,4,5-/1,2,3,4-Te MB ratio might not or slightly be affected by evaporative fractionation,biodegradation and thermal maturity.1,2,4,5-/1,2,3,4-Te MB ratio and 1,2,4,5-Te MB content can be used as supplementary parameter for the identification of sedimentary environment and organic matter input.It should be noted that compared to the identification of organic matter sources,the 1,2,4,5-/1,2,3,4-Te MB parameter is more effective in identifying sedimentary environments.
基金supported by the National Science and Technology Major Project(No.2016ZX05003-002-004)the National Natural Science Foundation of China(Nos.41072105,41872147,41503029)the National Key Research and Development Program of China(No.2017YFC0603102)。
文摘With comprehensive two-dimensional gas chromatography linked to time-of-flight mass spectrometry(GC × GC-TOFMS),ten light hydrocarbon(LH) compounds were qualitatively and quantitatively studied in light hydrocarbons(LHs) components of crude oils.For significant differences in the concentrations of 3-isoproyltoluene(3-iPT),4-isoproyltoluene(4-iPT) and 2-isoproyltoluene(2-iPT) in crude oils,and the 2-iPT probably derived mainly from similar skeleton monocyclic terpenoids via dehydrogenation and aromatization,the ratios of(3+4)-/2-iPT(iPTr),3-/2-iPT(iPTr1) and 4-/2-iPT(iPTr2) are proposed to distinguish the organic matter origin of crude oils.Relatively higher iPTr(>8.0),iPTr1(>7.0) and iPTr2(>4.0) values indicate that crude oils are sourced from the co-contribution of lower aquatic organisms,bacteria,algae,and terrestrial higher plants,whereas lower iPTr(<5.0),iPTr1(<3.0),iPTr2(<2.0) values suggest that crude oils originated from terrestrial higher plants.The iPTr,iPTr1,and iPTr2 values show notable distinction which is mainly controlled by 2-iPT concentrations,while the concentrations of 3-iPT and 4-iPT have similar distribution range in all studied oils.The 2-iPT depleted in marine oils from the Tarim Basin and lacustrine oils from the Beibuwan Basin is less than 0.30 mg/g LHs,whereas 2-iPT enriched in swamp oils from the Tarim Basin is greater than 0.50 mg/g LHs.The iPTr,iPTr1,and iPTr2 ratios and 2-iPT concentrations can be used to distinguish the organic matter origin of crude oils,especially for light oils and condensates with low concentrations of biomarkers.