ABSTRACT： The Damintun （大民屯） depression, a small （about 800km^2 in area） subunit in the Bohai （渤海） Bay basin, hosts nearly 2×10^8 t of high-wax oils with wax contents up to 60%. The high-wax oils have...ABSTRACT： The Damintun （大民屯） depression, a small （about 800km^2 in area） subunit in the Bohai （渤海） Bay basin, hosts nearly 2×10^8 t of high-wax oils with wax contents up to 60%. The high-wax oils have high consolidation temperatures and viscosities. The high-wax oils were generated from the fourth member of the Shahejie Formation （Es4）, which is also important source rocks for oils in other subunits of the Bohai Bay basin. Yet high-wax oils have not been found in significant volumes elsewhere in the Bohai Bay basin. Geological conditions favourable for high-wax oil enrichment were studied. This study shows that the unusual concentrations of high-wax oils in the depression seem to result from at least three different factors： （1） the presence of organic-matter rich source rocks which were prone to generate wax-rich hydrocarbons; （2） the formation of early overpressures which increased the expul- sion efficiency of waxy hydrocarbons; and （3） reductions in subsidence rate and basal heat flows, which minimized the thermal cracking of high molecular-weight （waxy） hydrocarbons, and therefore prevented the high-wax oils from being transformed into less waxy equivalents.展开更多
Some problems often occur in the analysis for petroleum samples by GC-MS.When high content wax composes oil samples,the n-alkanes in saturated fraction would disturb the mass chromatograph distribution and result of b...Some problems often occur in the analysis for petroleum samples by GC-MS.When high content wax composes oil samples,the n-alkanes in saturated fraction would disturb the mass chromatograph distribution and result of biomarkers.The n-alkanes can be removed from the saturated fraction by complexation,which n-alkanes react with carbamide supersaturated in methanol solution.Nevertheless,levels of the complexation can also affect on the mass chromatograph distribution and result of biomarkers.This paper discusses these problems and measures.展开更多
基金supported by the National Natural Science Foundation of China (No. 40772089)
文摘ABSTRACT： The Damintun （大民屯） depression, a small （about 800km^2 in area） subunit in the Bohai （渤海） Bay basin, hosts nearly 2×10^8 t of high-wax oils with wax contents up to 60%. The high-wax oils have high consolidation temperatures and viscosities. The high-wax oils were generated from the fourth member of the Shahejie Formation （Es4）, which is also important source rocks for oils in other subunits of the Bohai Bay basin. Yet high-wax oils have not been found in significant volumes elsewhere in the Bohai Bay basin. Geological conditions favourable for high-wax oil enrichment were studied. This study shows that the unusual concentrations of high-wax oils in the depression seem to result from at least three different factors： （1） the presence of organic-matter rich source rocks which were prone to generate wax-rich hydrocarbons; （2） the formation of early overpressures which increased the expul- sion efficiency of waxy hydrocarbons; and （3） reductions in subsidence rate and basal heat flows, which minimized the thermal cracking of high molecular-weight （waxy） hydrocarbons, and therefore prevented the high-wax oils from being transformed into less waxy equivalents.
文摘Some problems often occur in the analysis for petroleum samples by GC-MS.When high content wax composes oil samples,the n-alkanes in saturated fraction would disturb the mass chromatograph distribution and result of biomarkers.The n-alkanes can be removed from the saturated fraction by complexation,which n-alkanes react with carbamide supersaturated in methanol solution.Nevertheless,levels of the complexation can also affect on the mass chromatograph distribution and result of biomarkers.This paper discusses these problems and measures.
