Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） ...Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） has been investigated using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry（GC×GC-To FMS） within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan（Neoproterozoic, marine）, Tarim（Early Paleozoic, marine）, Bohai Bay（Eocene, saline/brackish） and Pearl River Mouth（Eocene, freshwater）. In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A-norsteranes, series of 1,1,3-trimethyl-2-alkylcyclohexanes（carotenoid-derived alkanes）, and tetralin and indane compounds, respectively.展开更多
It is a challenge to determine the source and genetic relationship of condensate, waxy and heavy oils in one given complicated petroliferous area, where developed multiple sets of source rocks with different maturity ...It is a challenge to determine the source and genetic relationship of condensate, waxy and heavy oils in one given complicated petroliferous area, where developed multiple sets of source rocks with different maturity and various chemical features.The central part of southern margin of Junggar Basin, NW China is such an example where there are condensates, light oils, normal density oils, heavy crude oils and natural gases. The formation mechanism of condensates has been seriously debated for long time;however, no study has integrated it with genetic types of waxy and heavy oils. Taking the central part of southern margin of Junggar Basin as a case, this study employs geological and geochemical methods to determine the formation mechanism of condensates,waxy and heavy oils in a complicated petroliferous area, and reveals the causes and geochemical processes of the co-occurrence of different types of crude oils in this region. Based on detailed geochemical analyses of more than 40 normal crude oils, light oils,condensates and heavy oils, it is found that the condensates are dominated by low carbon number n-alkanes and enriched in light naphthenics and aromatic hydrocarbons. Heptane values of these condensates range from 19% to 21%, isoheptane values from1.9 to 2.1, and toluene/n-heptane ratios from 1.5 to 2.0. The distribution of n-alkanes in the condensates presents a mirror image with high density waxy crude oils and heavy oils. Combined with the oil and gas-source correlations of the crude oils, condensates and natural gas, it is found that the condensates are product of evaporative fractionation and/or phase-controlled fractionation of reservoir crude oils which were derived from mature Cretaceous lacustrine source rocks in the relatively early stage. The waxy oils are the intermediate products of evaporative fractionation and/or phase-controlled fractionation of reservoir crude oils, while the heavy oils are in-situ residuals. Therefore, evaporative fractionation and/or phase-controlled fractionation would account for the formation of the condensate, light oil, waxy oil and heavy oil in the central part of southern margin of Junggar Basin, resulting in a great change of the content in terms of light alkanes, naphthenics and aromatics in condensates, followed by great uncertainties of toluene/n-heptane ratios due to migration and re-accumulation. The results suggest that the origin of the condensate cannot be simply concluded by its ratios of toluene/n-heptane and n-heptane/methylcyclohexane on the Thompson's cross-plot, it should be comprehensively determined by the aspects of geological background, thermal history of source rocks and petroleum generation,physical and chemical features of various crude oils and natural gas, vertical and lateral distribution of various crude oils in the study area.展开更多
Twenty-five monoterpanes from six types of essential oils and hydrogenated turpentine oil have been identified and their stable carbon isotope composition determined.Monoterpanes in essential oils sourced from terrest...Twenty-five monoterpanes from six types of essential oils and hydrogenated turpentine oil have been identified and their stable carbon isotope composition determined.Monoterpanes in essential oils sourced from terrestrial higher plants display a δ13C value in the range of-34‰-26‰,and mostly between-29‰ and-27‰.The δ13C value of any single monoterpane is very consistent in different essential oils.Acyclic monoterpanes show closer isotope composition between-28.6‰ and-26.2‰,with an average value of-27.7‰.In contrast,the isotope composition of cyclic monoterpanes is more scattered with an average value of-28.6‰.Isotopic fractionation with 13C enrichment has been observed during both artificial and geological hydrogenation of monoterpenoids to monoterpanes,and this is more obvious for the acyclic monoterpenoids.In addition to higher plants,acyclic monoterpane 2,6-dimethylheptane in crude oil can also be originated from other organic inputs.展开更多
Various △5-3β-sterenols, whose carbon numbers range from C19―C23 to C26―C30 and some compounds have many stereomers maximal up to six, have been detected out from the extract of brown algae (Sargassum muticum), wh...Various △5-3β-sterenols, whose carbon numbers range from C19―C23 to C26―C30 and some compounds have many stereomers maximal up to six, have been detected out from the extract of brown algae (Sargassum muticum), which means that steranes with lower carbon numbers are likely dif- ferent in the origin, and some corresponding sterol stereoisomers may have already existed in their precursor organisms. This provides some experi- mental evidence for supplementing and amending the traditional interpretation of the sterol stereoisomer transformation during the deposition and diagenesis of organic matter.展开更多
Objective To explore the effectiveness and safety of the combined treatment with acupuncture and venlafaxine hydrochloride on depression in terms of the microstructure change of white matter fiber tracts of brain base...Objective To explore the effectiveness and safety of the combined treatment with acupuncture and venlafaxine hydrochloride on depression in terms of the microstructure change of white matter fiber tracts of brain based on diffusion tensor imaging technology(DTI).Methods The prospective study design was adopted.All of 60 patients with depression were randomized into an acupuncture-medication group and a medication group,30 cases in each one.In the medication group,venlafaxine hydrochloride was used,75 mg per day in the 1st week,150 mg per day in the 2nd week and 225 mg per day from the 3rd to 6th week.In the acupuncture-medication group,on the base of the treatment in the medication group,acupuncture was combined.Baihui(GV 20)and Yintang(GV 29)were the main acupoints.The supplementary acupoints were selected according to the clinical symptoms of individuals.The needles were retained for 30 min.Acupuncture was provided once every 2 days,3 times a week.The consecutive 12 weeks of treatment were required in the two groups.Additionally,a normal group was prepared with 30 healthy volunteers.Separately,before treatment,in 2,8 and 12 weeks of treatment,Hamilton’s depression scale(HAMD-17),Beck depression inventory scale(BDI)and the antidepressant side effect scale(SERS)were adopted to evaluate the effectiveness and safety of the two groups.Moreover,before and after 12 weeks of treatment,DTI was adopted to detect the fractional anisotropy score(FA)of each brain region in the patients.Results After treatment,the scores of HAMD-17 and BDI were all reduced in the two groups(P<0.05).In 8 and 12 weeks of treatment,the scores of HAMD-17 and BDI in the acupuncture-medication group were less than those in the medication group(P<0.05).The difference in SERS score was not significant statistically between the two groups(P>0.05).Compared with the healthy volunteers,FA scores in 6 brain regions changed obviously in the patients with depression,including the white matter of bilateral frontal lobes,splenium of corpus callosum,left cingulated gyrus,white matter of bilateral inferior temporal gyrus,white matter of bilateral inferior parietal lobe and white matter of bilateral deep temporal occipital region separately.Before treatment,the differences in FA scores of these 6 brain regions were not significant statistically between the two groups(P>0.05).After treatment,FA scores in the white matter of bilateral frontal lobes,white matter of bilateral inferior temporal gyrus and white matter of bilateral deep temporal occipital region in the acupuncture-medication group were all higher than those in the medication group(P<0.05).Conclusion Acupuncture repairs the brain white matter fiber tracts in some brain regions to certain extent and the therapeutic effects are enhanced with the adjuvant medication of venlafaxine hydrochloride.展开更多
基金funded by the National Natural Science Foundation of China(Grant No.41172126)the State Key Laboratory of Petroleum Resources and Prospecting(PRP/indep-2-1402)
文摘Heavy biodegraded crude oils have larger numbers of coeluting compounds than nonbiodegraded oils, and they are typically not resolved with conventional gas chromatography（GC）. This unresolved complex mixture（UCM） has been investigated using comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry（GC×GC-To FMS） within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan（Neoproterozoic, marine）, Tarim（Early Paleozoic, marine）, Bohai Bay（Eocene, saline/brackish） and Pearl River Mouth（Eocene, freshwater）. In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A-norsteranes, series of 1,1,3-trimethyl-2-alkylcyclohexanes（carotenoid-derived alkanes）, and tetralin and indane compounds, respectively.
基金supported by the PetroChina Science and Technology Special Projects (Grant Nos. 06-10A-01-02, 2011A-0201, 2014A-0211 and 2016A-0202)
文摘It is a challenge to determine the source and genetic relationship of condensate, waxy and heavy oils in one given complicated petroliferous area, where developed multiple sets of source rocks with different maturity and various chemical features.The central part of southern margin of Junggar Basin, NW China is such an example where there are condensates, light oils, normal density oils, heavy crude oils and natural gases. The formation mechanism of condensates has been seriously debated for long time;however, no study has integrated it with genetic types of waxy and heavy oils. Taking the central part of southern margin of Junggar Basin as a case, this study employs geological and geochemical methods to determine the formation mechanism of condensates,waxy and heavy oils in a complicated petroliferous area, and reveals the causes and geochemical processes of the co-occurrence of different types of crude oils in this region. Based on detailed geochemical analyses of more than 40 normal crude oils, light oils,condensates and heavy oils, it is found that the condensates are dominated by low carbon number n-alkanes and enriched in light naphthenics and aromatic hydrocarbons. Heptane values of these condensates range from 19% to 21%, isoheptane values from1.9 to 2.1, and toluene/n-heptane ratios from 1.5 to 2.0. The distribution of n-alkanes in the condensates presents a mirror image with high density waxy crude oils and heavy oils. Combined with the oil and gas-source correlations of the crude oils, condensates and natural gas, it is found that the condensates are product of evaporative fractionation and/or phase-controlled fractionation of reservoir crude oils which were derived from mature Cretaceous lacustrine source rocks in the relatively early stage. The waxy oils are the intermediate products of evaporative fractionation and/or phase-controlled fractionation of reservoir crude oils, while the heavy oils are in-situ residuals. Therefore, evaporative fractionation and/or phase-controlled fractionation would account for the formation of the condensate, light oil, waxy oil and heavy oil in the central part of southern margin of Junggar Basin, resulting in a great change of the content in terms of light alkanes, naphthenics and aromatics in condensates, followed by great uncertainties of toluene/n-heptane ratios due to migration and re-accumulation. The results suggest that the origin of the condensate cannot be simply concluded by its ratios of toluene/n-heptane and n-heptane/methylcyclohexane on the Thompson's cross-plot, it should be comprehensively determined by the aspects of geological background, thermal history of source rocks and petroleum generation,physical and chemical features of various crude oils and natural gas, vertical and lateral distribution of various crude oils in the study area.
基金supported by National Natural Science Foundation of China (Grant No.40573030)National High-Tech Research & Development Program of China (Grant No.2007AA06A211)
文摘Twenty-five monoterpanes from six types of essential oils and hydrogenated turpentine oil have been identified and their stable carbon isotope composition determined.Monoterpanes in essential oils sourced from terrestrial higher plants display a δ13C value in the range of-34‰-26‰,and mostly between-29‰ and-27‰.The δ13C value of any single monoterpane is very consistent in different essential oils.Acyclic monoterpanes show closer isotope composition between-28.6‰ and-26.2‰,with an average value of-27.7‰.In contrast,the isotope composition of cyclic monoterpanes is more scattered with an average value of-28.6‰.Isotopic fractionation with 13C enrichment has been observed during both artificial and geological hydrogenation of monoterpenoids to monoterpanes,and this is more obvious for the acyclic monoterpenoids.In addition to higher plants,acyclic monoterpane 2,6-dimethylheptane in crude oil can also be originated from other organic inputs.
文摘Various △5-3β-sterenols, whose carbon numbers range from C19―C23 to C26―C30 and some compounds have many stereomers maximal up to six, have been detected out from the extract of brown algae (Sargassum muticum), which means that steranes with lower carbon numbers are likely dif- ferent in the origin, and some corresponding sterol stereoisomers may have already existed in their precursor organisms. This provides some experi- mental evidence for supplementing and amending the traditional interpretation of the sterol stereoisomer transformation during the deposition and diagenesis of organic matter.
文摘Objective To explore the effectiveness and safety of the combined treatment with acupuncture and venlafaxine hydrochloride on depression in terms of the microstructure change of white matter fiber tracts of brain based on diffusion tensor imaging technology(DTI).Methods The prospective study design was adopted.All of 60 patients with depression were randomized into an acupuncture-medication group and a medication group,30 cases in each one.In the medication group,venlafaxine hydrochloride was used,75 mg per day in the 1st week,150 mg per day in the 2nd week and 225 mg per day from the 3rd to 6th week.In the acupuncture-medication group,on the base of the treatment in the medication group,acupuncture was combined.Baihui(GV 20)and Yintang(GV 29)were the main acupoints.The supplementary acupoints were selected according to the clinical symptoms of individuals.The needles were retained for 30 min.Acupuncture was provided once every 2 days,3 times a week.The consecutive 12 weeks of treatment were required in the two groups.Additionally,a normal group was prepared with 30 healthy volunteers.Separately,before treatment,in 2,8 and 12 weeks of treatment,Hamilton’s depression scale(HAMD-17),Beck depression inventory scale(BDI)and the antidepressant side effect scale(SERS)were adopted to evaluate the effectiveness and safety of the two groups.Moreover,before and after 12 weeks of treatment,DTI was adopted to detect the fractional anisotropy score(FA)of each brain region in the patients.Results After treatment,the scores of HAMD-17 and BDI were all reduced in the two groups(P<0.05).In 8 and 12 weeks of treatment,the scores of HAMD-17 and BDI in the acupuncture-medication group were less than those in the medication group(P<0.05).The difference in SERS score was not significant statistically between the two groups(P>0.05).Compared with the healthy volunteers,FA scores in 6 brain regions changed obviously in the patients with depression,including the white matter of bilateral frontal lobes,splenium of corpus callosum,left cingulated gyrus,white matter of bilateral inferior temporal gyrus,white matter of bilateral inferior parietal lobe and white matter of bilateral deep temporal occipital region separately.Before treatment,the differences in FA scores of these 6 brain regions were not significant statistically between the two groups(P>0.05).After treatment,FA scores in the white matter of bilateral frontal lobes,white matter of bilateral inferior temporal gyrus and white matter of bilateral deep temporal occipital region in the acupuncture-medication group were all higher than those in the medication group(P<0.05).Conclusion Acupuncture repairs the brain white matter fiber tracts in some brain regions to certain extent and the therapeutic effects are enhanced with the adjuvant medication of venlafaxine hydrochloride.
