The origin and source of the petroleum in the Jurassic reservoirs within the eastern Fukang sub-depression were geochemically investigated.They show thermal maturities matching the peak generation stage,while the cond...The origin and source of the petroleum in the Jurassic reservoirs within the eastern Fukang sub-depression were geochemically investigated.They show thermal maturities matching the peak generation stage,while the condensates are at the early stage of intense cracking.Oils and condensates may have experienced mild evaporative fractionation,while mixing of severely biodegraded with non-biodegraded oils has occurred.Using biomarkers and isotopes,petroleums were classified into GroupⅠ,ⅡandⅢgenetic groups,with GroupⅢfurther divided intoⅢa andⅢb subgroups.GroupⅠpetroleum displays heavy carbon isotopes,a strong predominance of pristine over phytane,high C_(19)and C_(20)tricyclic and C_(24)tetracyclic terpanes,low gammacerane,and dominant C_(29)steranes,while GroupⅡshows light carbon isotopes,a predominance of phytane over pristine,high C_(21)and C_(23)tricyclic with low C_(24)tetracyclic terpanes,high gammacerane and dominant C_(27)steranes.GroupⅢa petroleum shows mixing compositions of GroupⅠandⅡ,while GroupⅢb displays similar compositions to Group I,but with significantly higher Ts,C_(29)Ts and C_(30)diahopane proportions.Oil-source rock correlation suggests GroupⅠandⅡpetroleums originate from Jurassic and Permian source rocks,respectively,while GroupⅢa are mixtures sourced from these rocks andⅢb are mixtures from Jurassic and Triassic source rocks.展开更多
In Turpan-Hami basin,multi-source rocks are developed in Xiaocaohu secondary sag,and show good source conditions,abundant petroleum resources and bright prospects for exploration.Three reservoir-cap assemblages develo...In Turpan-Hami basin,multi-source rocks are developed in Xiaocaohu secondary sag,and show good source conditions,abundant petroleum resources and bright prospects for exploration.Three reservoir-cap assemblages developed in Middle Jurassic formed reservoir types in the sag which are structural-lithology oil-gas pools in Sanjian fang formation and Qiketai formation along with deep basinal gas pools in Xishanyao formation of Jurassic.The late Yanshan movement is a major stage for hydrocarbon accumulation in Xiaocaohu secondary sag.The primary controlled factors for its hydrocarbon accumulation is due to its palaeo-structures,tectonic setting and traps with structural-litholo gy feature.The exploratory efforts has good effectiveness based on these main controlled factors for evaluation and optimization of its favorable zones.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.20CX02108A)the Development Fund of the Key Laboratory of Deep Oil&Gas,China University of Petroleum(East China)。
文摘The origin and source of the petroleum in the Jurassic reservoirs within the eastern Fukang sub-depression were geochemically investigated.They show thermal maturities matching the peak generation stage,while the condensates are at the early stage of intense cracking.Oils and condensates may have experienced mild evaporative fractionation,while mixing of severely biodegraded with non-biodegraded oils has occurred.Using biomarkers and isotopes,petroleums were classified into GroupⅠ,ⅡandⅢgenetic groups,with GroupⅢfurther divided intoⅢa andⅢb subgroups.GroupⅠpetroleum displays heavy carbon isotopes,a strong predominance of pristine over phytane,high C_(19)and C_(20)tricyclic and C_(24)tetracyclic terpanes,low gammacerane,and dominant C_(29)steranes,while GroupⅡshows light carbon isotopes,a predominance of phytane over pristine,high C_(21)and C_(23)tricyclic with low C_(24)tetracyclic terpanes,high gammacerane and dominant C_(27)steranes.GroupⅢa petroleum shows mixing compositions of GroupⅠandⅡ,while GroupⅢb displays similar compositions to Group I,but with significantly higher Ts,C_(29)Ts and C_(30)diahopane proportions.Oil-source rock correlation suggests GroupⅠandⅡpetroleums originate from Jurassic and Permian source rocks,respectively,while GroupⅢa are mixtures sourced from these rocks andⅢb are mixtures from Jurassic and Triassic source rocks.
文摘In Turpan-Hami basin,multi-source rocks are developed in Xiaocaohu secondary sag,and show good source conditions,abundant petroleum resources and bright prospects for exploration.Three reservoir-cap assemblages developed in Middle Jurassic formed reservoir types in the sag which are structural-lithology oil-gas pools in Sanjian fang formation and Qiketai formation along with deep basinal gas pools in Xishanyao formation of Jurassic.The late Yanshan movement is a major stage for hydrocarbon accumulation in Xiaocaohu secondary sag.The primary controlled factors for its hydrocarbon accumulation is due to its palaeo-structures,tectonic setting and traps with structural-litholo gy feature.The exploratory efforts has good effectiveness based on these main controlled factors for evaluation and optimization of its favorable zones.
