Aromatic fractions of 140 oils and condensates that originated from different types of source rocks （marine shale,terrestrial shale and marine carbonate） were analyzed using gas chromatographymass spectrometry （GC...Aromatic fractions of 140 oils and condensates that originated from different types of source rocks （marine shale,terrestrial shale and marine carbonate） were analyzed using gas chromatographymass spectrometry （GC-MS） to investigate the relative distributions of methylated dibenzothiophenes with respect to thermal maturity.The positions of methyl groups of trimethyldibenzothiophene isomers （TMDBTs） including those used in the definition of maturity indicator TMDBT index in previous studies were firmly identified by co-elution of internal standards in GC-MS analysis and by comparing with reported retention indices.A new maturity ratio related to dimethyldibenzothiophenes （DMDBTs） is proposed on the basis of the differences in thermodynamic stability among different DMDBT isomers.Another maturity index （TMDBT-I2） based on TMDBTs is also suggested on the basis of our empirical observations and presumed thermodynamic stability of TMDBT isomers.These two newly proposed （2,6 ＋ 3,6）-/1,4-DMDBT ratio and TMDBT-I2 correlate well with MDR （4-/1-methyldibenzothiophene）and 2,4-/1,4-DMDBT ratios,suggesting their common chemical reaction mechanisms and similar behavior with increasing maturity.Therefore,they can be effectively applied for maturity assessments.Furthermore,the TMDBTs related maturity parameters are more reliable for over-mature oils and condensates due to the relatively higher concentrations of thermodynamically unstable TMDBT isomers,i.e.1,4,6-,1,4,8-and 3,4,6-TMDBT in this study than those of 1-methyldibenzothiophene （1-MDBT） or 1,4-DMDBT.In contrast with 4,6-/1,4-DMDBT,the newly proposed （2,6 ＋ 3,6）-/1,4-DMDBT ratios for oils that originated from different types of source rocks have approximately same relationship with the oil maturity （Rc %）.This suggests that the lithology and organic facies may have relatively less influence on （2,6 ＋ 3,6）-/1,4-DMDBT ratio compared to 4,6-/1,4-DMDBT.The maturity parameters based on methylated dibenzothiophenes are particula展开更多
Two nondestructive methods based on visible and near-infrared(VIS-NIR)spectroscopy and X-ray image have been used for the evaluation of watermelon quality.The prediction perform-ance based on partial least squares(PLS...Two nondestructive methods based on visible and near-infrared(VIS-NIR)spectroscopy and X-ray image have been used for the evaluation of watermelon quality.The prediction perform-ance based on partial least squares(PLS)by diffuse transmittance measurement(500-1010 nm)was evaluated for_chemical quality attributes SSC(Rc=0.903;RMSEC=0.572%Brix;Rp=0.862;RMSEP=0.717%Brix;RPD=1.83),lycopene(Rc=0.845;RMSEC=0.266 mg/100 gFW;Rp=0.751;RMSEP=0.439 mg/100 gFW;RPD=1.13)and moisture(Rc=0.917;RMSEC=0.280%;Rp=0.937;RMSEP=0.276%;RPD=2.79).The X-ray calibration linearequations developed by extracting the appropriate gray threshold were sufficiently precise forvolume(R?=0.986)and weight(R?=0.993).In order to optimize prediction model of water-melon quality in growth period,multivariate multi-block technique factor analysis enabled in-tegration of these traits:chemical information is related to physical infomation.Applyingprinciple component analysis to extract common factors and varimax with Kaiser normalizationto improve explanatory,the comprehensive indicator based on variances was established satis.factorily with Rc=0.94,RMSEC=0.244,Rp=0.93,RMSEP=0.344 and RPD=2.00.Acomparison of these models indicates that the comprehensive indicator determined only by portable VIS-NIR spectrometer appears as a suitable method for appraising watermelon qualitynondestructively on the plant at diferent ripen stages.This method contributes to infer the picking date of watermelon with higher accuracy and bigger economic benefits than that byexperience.展开更多
The original gas reservoirs in different areas and different layers of the Triassic Xujiahe Formation in the central Sichuan Basin are studied to reveal the relationships of iC4/nC4 and iC5/nC5 ratios in coal-derived ...The original gas reservoirs in different areas and different layers of the Triassic Xujiahe Formation in the central Sichuan Basin are studied to reveal the relationships of iC4/nC4 and iC5/nC5 ratios in coal-derived gas components with maturity using conventional natural gas geochemical research methods. The testing results of 73 gas samples from 8 gas fields show that the iC4/nC4 and iC5/nC5 ratios in coal-derived gas have a good positive correlation, and the correlation coefficient is above 0.8. Both the iC4/nC4 and iC5/nC5 ratios become higher with the increase of natural gas dryness coefficient (C1/C1+) and the methane carbon isotope becoming less negative. These parameters are highly correlated. This study not only reveals characteristics of heavy hydrocarbon isomers generated by coal formation, but also puts forward new identification indicators reflecting the maturity of coal-derived gas, the regression between iC4/nC4, iC5/nC5 and Ro, which can provide an important reference for maturity, migration and accumulation of coal-derived gas, and late stage reformation of coal-derived gas reservoirs.展开更多
基金funded by the National Natural Science Foundation of China (Grant No. 41272158)the State Key Laboratory of Petroleum Resources and Prospecting (PRP/indep-2-1302)
文摘Aromatic fractions of 140 oils and condensates that originated from different types of source rocks （marine shale,terrestrial shale and marine carbonate） were analyzed using gas chromatographymass spectrometry （GC-MS） to investigate the relative distributions of methylated dibenzothiophenes with respect to thermal maturity.The positions of methyl groups of trimethyldibenzothiophene isomers （TMDBTs） including those used in the definition of maturity indicator TMDBT index in previous studies were firmly identified by co-elution of internal standards in GC-MS analysis and by comparing with reported retention indices.A new maturity ratio related to dimethyldibenzothiophenes （DMDBTs） is proposed on the basis of the differences in thermodynamic stability among different DMDBT isomers.Another maturity index （TMDBT-I2） based on TMDBTs is also suggested on the basis of our empirical observations and presumed thermodynamic stability of TMDBT isomers.These two newly proposed （2,6 ＋ 3,6）-/1,4-DMDBT ratio and TMDBT-I2 correlate well with MDR （4-/1-methyldibenzothiophene）and 2,4-/1,4-DMDBT ratios,suggesting their common chemical reaction mechanisms and similar behavior with increasing maturity.Therefore,they can be effectively applied for maturity assessments.Furthermore,the TMDBTs related maturity parameters are more reliable for over-mature oils and condensates due to the relatively higher concentrations of thermodynamically unstable TMDBT isomers,i.e.1,4,6-,1,4,8-and 3,4,6-TMDBT in this study than those of 1-methyldibenzothiophene （1-MDBT） or 1,4-DMDBT.In contrast with 4,6-/1,4-DMDBT,the newly proposed （2,6 ＋ 3,6）-/1,4-DMDBT ratios for oils that originated from different types of source rocks have approximately same relationship with the oil maturity （Rc %）.This suggests that the lithology and organic facies may have relatively less influence on （2,6 ＋ 3,6）-/1,4-DMDBT ratio compared to 4,6-/1,4-DMDBT.The maturity parameters based on methylated dibenzothiophenes are particula
基金supported by the national nat uralscience foundation(NSFC)(NO.31071555)to provide financial support and the earmarked fund for Modern Agro-industry Technology Research System(NO.CARS-26-22)to measure referencevalues using traditional methods.
文摘Two nondestructive methods based on visible and near-infrared(VIS-NIR)spectroscopy and X-ray image have been used for the evaluation of watermelon quality.The prediction perform-ance based on partial least squares(PLS)by diffuse transmittance measurement(500-1010 nm)was evaluated for_chemical quality attributes SSC(Rc=0.903;RMSEC=0.572%Brix;Rp=0.862;RMSEP=0.717%Brix;RPD=1.83),lycopene(Rc=0.845;RMSEC=0.266 mg/100 gFW;Rp=0.751;RMSEP=0.439 mg/100 gFW;RPD=1.13)and moisture(Rc=0.917;RMSEC=0.280%;Rp=0.937;RMSEP=0.276%;RPD=2.79).The X-ray calibration linearequations developed by extracting the appropriate gray threshold were sufficiently precise forvolume(R?=0.986)and weight(R?=0.993).In order to optimize prediction model of water-melon quality in growth period,multivariate multi-block technique factor analysis enabled in-tegration of these traits:chemical information is related to physical infomation.Applyingprinciple component analysis to extract common factors and varimax with Kaiser normalizationto improve explanatory,the comprehensive indicator based on variances was established satis.factorily with Rc=0.94,RMSEC=0.244,Rp=0.93,RMSEP=0.344 and RPD=2.00.Acomparison of these models indicates that the comprehensive indicator determined only by portable VIS-NIR spectrometer appears as a suitable method for appraising watermelon qualitynondestructively on the plant at diferent ripen stages.This method contributes to infer the picking date of watermelon with higher accuracy and bigger economic benefits than that byexperience.
基金Supported by the National Natural Science Foundation of China(41872162)
文摘The original gas reservoirs in different areas and different layers of the Triassic Xujiahe Formation in the central Sichuan Basin are studied to reveal the relationships of iC4/nC4 and iC5/nC5 ratios in coal-derived gas components with maturity using conventional natural gas geochemical research methods. The testing results of 73 gas samples from 8 gas fields show that the iC4/nC4 and iC5/nC5 ratios in coal-derived gas have a good positive correlation, and the correlation coefficient is above 0.8. Both the iC4/nC4 and iC5/nC5 ratios become higher with the increase of natural gas dryness coefficient (C1/C1+) and the methane carbon isotope becoming less negative. These parameters are highly correlated. This study not only reveals characteristics of heavy hydrocarbon isomers generated by coal formation, but also puts forward new identification indicators reflecting the maturity of coal-derived gas, the regression between iC4/nC4, iC5/nC5 and Ro, which can provide an important reference for maturity, migration and accumulation of coal-derived gas, and late stage reformation of coal-derived gas reservoirs.
