Geological mapping,interpreted cross sections,structural analyses and residual thickness maps were used to characterize the evolution of stress setting,structure and stratigraphic distribution of the Chepaizi Uplift,w...Geological mapping,interpreted cross sections,structural analyses and residual thickness maps were used to characterize the evolution of stress setting,structure and stratigraphic distribution of the Chepaizi Uplift,which is a NW-SE trending structure located in the Western Junggar Basin.The NS-trending faults show an important transpressional phase during the Late Permian,as demonstrated by tectonic stress field and stratigraphic thickness variations.A major compressional thrusting and strike-slip phase during the Late Jurassic created a series of NW-SE faults that originated by the large-scale uplift event in the Northern Tianshan.Faults were reactivated as thrust and dextral strike-slip faults.In addition,the angular unconformity observed between Jurassic and Cretaceous provide evidence of this tectonic event.Lots of normal faults indicate that the area records southward tilting and regional derived extensional stress that took place during the Neogene.Before that,thick Early Cenozoic strata are widely deposited.The balanced cross-section highlights the evolution of stress setting and stratigraphic distribution of the Chepaizi Uplift.展开更多
So far there has been no common opinion on oil source of the Chepaizi swell in the Junggar Basin. Therefore, it is difficult to determine the pathway system and trend of hydrocarbon migration, and this resulted in dif...So far there has been no common opinion on oil source of the Chepaizi swell in the Junggar Basin. Therefore, it is difficult to determine the pathway system and trend of hydrocarbon migration, and this resulted in difficulties in study of oil-gas accumulation patterns. In this paper, study of nitrogen compounds distribution in oils from Chepaizi was carried out in order to classify source rocks of oils stored in different reservoirs in the study area. Then, migration characteristics of oils from the same source were investigated by using nitrogen compounds parameters. The results of nitrogen compounds in a group of oil/oil sand samples from the same source indicate that the oils trapped in the Chepaizi swell experienced an obvious vertical migration. With increasing migration distance, amounts and indices of carbazoles have a regular changing pattern （in a fine linear relationship）. By using nitrogen compounds techniques, the analyzed oil/oil sand samples of Chepaizi can be classified into two groups. One is the samples stored in reservoir beds of the Cretaceous and Tertiary, and these oils came from mainly Jurassic source rock with a small amount of Cretaceous rock; the other is those stored in the Jurassic, Permian and Carboniferous beds, and they originated from the Permian source. In addition, a sample of oil from an upper Jurassic reservoir （Well Ka 6）, which was generated from Jurassic coal source rock, has a totally different nitrogen compound distribution from those of the above-mentioned two groups of samples, which were generated from mudstone sources. Because of influence from fractionation of oil migration, amounts and ratios of nitrogen compounds with different structures and polarities change regularly with increasing migrating distance, and as a result the samples with the same source follow a good linear relationship in content and ratio, while the oil samples of different sources have obviously different nitrogen compound distribution owing to different organic matter types of their sourc展开更多
Well che89,located in the Chepaizi area in the northwest margin of Junggar basin,acquires high production industrial oil flow,which is an important breakthrough in the exploration of the south foreland slope area of J...Well che89,located in the Chepaizi area in the northwest margin of Junggar basin,acquires high production industrial oil flow,which is an important breakthrough in the exploration of the south foreland slope area of Junggar basin. The Chepaizi area is near two hydrocarbon generation depressions of Sikeshu and Shawan,which have sets of hydrocarbon source rock of Carboniferous to Jurassic as well as Upper Tertiary. Geological and geochemical parameters are proper for the accumulation of mixed source crude oil. Carbon isotope,group composition and biomarkers of crude oil in Upper Tertiary of well Che89 show that the features of crude oil in Upper Tertiary Shawan Formation are between that of Permian and Jurassic,some of them are similar to these two,and some are of difference,they should be the mixed source of Permian and Jurassic. Geochemical analysis and geological study show that sand extract of Lower Tertiary Wulunguhe Formation has the same source as the crude oil and sand extract of Upper Tertiary Shawan Formation,but they are not charged in the same period. Oil/gas of Wulunguhe Formation is charged before Upper Tertiary sedimentation,and suffered serious biodegradation and oxidation and rinsing,which provide a proof in another aspect that the crude oil of Upper Tertiary Shawan Formation of well Che89 is not from hydrocarbon source rock of Lower Tertiary.展开更多
基金financially supported by the Natural Sciences Foundation of China(Chen S.,grant number 41502208)Science Foundation of China University of Petroleum(Chen S.,grant number 2462017BJB01)CNPC Innovation Foundation(Chen S.,grant number 2017D-5007-0103)
文摘Geological mapping,interpreted cross sections,structural analyses and residual thickness maps were used to characterize the evolution of stress setting,structure and stratigraphic distribution of the Chepaizi Uplift,which is a NW-SE trending structure located in the Western Junggar Basin.The NS-trending faults show an important transpressional phase during the Late Permian,as demonstrated by tectonic stress field and stratigraphic thickness variations.A major compressional thrusting and strike-slip phase during the Late Jurassic created a series of NW-SE faults that originated by the large-scale uplift event in the Northern Tianshan.Faults were reactivated as thrust and dextral strike-slip faults.In addition,the angular unconformity observed between Jurassic and Cretaceous provide evidence of this tectonic event.Lots of normal faults indicate that the area records southward tilting and regional derived extensional stress that took place during the Neogene.Before that,thick Early Cenozoic strata are widely deposited.The balanced cross-section highlights the evolution of stress setting and stratigraphic distribution of the Chepaizi Uplift.
基金supported by the State 973 Funds(No. 2006CB202308)
文摘So far there has been no common opinion on oil source of the Chepaizi swell in the Junggar Basin. Therefore, it is difficult to determine the pathway system and trend of hydrocarbon migration, and this resulted in difficulties in study of oil-gas accumulation patterns. In this paper, study of nitrogen compounds distribution in oils from Chepaizi was carried out in order to classify source rocks of oils stored in different reservoirs in the study area. Then, migration characteristics of oils from the same source were investigated by using nitrogen compounds parameters. The results of nitrogen compounds in a group of oil/oil sand samples from the same source indicate that the oils trapped in the Chepaizi swell experienced an obvious vertical migration. With increasing migration distance, amounts and indices of carbazoles have a regular changing pattern （in a fine linear relationship）. By using nitrogen compounds techniques, the analyzed oil/oil sand samples of Chepaizi can be classified into two groups. One is the samples stored in reservoir beds of the Cretaceous and Tertiary, and these oils came from mainly Jurassic source rock with a small amount of Cretaceous rock; the other is those stored in the Jurassic, Permian and Carboniferous beds, and they originated from the Permian source. In addition, a sample of oil from an upper Jurassic reservoir （Well Ka 6）, which was generated from Jurassic coal source rock, has a totally different nitrogen compound distribution from those of the above-mentioned two groups of samples, which were generated from mudstone sources. Because of influence from fractionation of oil migration, amounts and ratios of nitrogen compounds with different structures and polarities change regularly with increasing migrating distance, and as a result the samples with the same source follow a good linear relationship in content and ratio, while the oil samples of different sources have obviously different nitrogen compound distribution owing to different organic matter types of their sourc
基金Supported by National Natural Science Foundation of China (Grant Nos. 40602013 and 40572078)Doctor’s Foundation (Grant No. 20060489002)
文摘Well che89,located in the Chepaizi area in the northwest margin of Junggar basin,acquires high production industrial oil flow,which is an important breakthrough in the exploration of the south foreland slope area of Junggar basin. The Chepaizi area is near two hydrocarbon generation depressions of Sikeshu and Shawan,which have sets of hydrocarbon source rock of Carboniferous to Jurassic as well as Upper Tertiary. Geological and geochemical parameters are proper for the accumulation of mixed source crude oil. Carbon isotope,group composition and biomarkers of crude oil in Upper Tertiary of well Che89 show that the features of crude oil in Upper Tertiary Shawan Formation are between that of Permian and Jurassic,some of them are similar to these two,and some are of difference,they should be the mixed source of Permian and Jurassic. Geochemical analysis and geological study show that sand extract of Lower Tertiary Wulunguhe Formation has the same source as the crude oil and sand extract of Upper Tertiary Shawan Formation,but they are not charged in the same period. Oil/gas of Wulunguhe Formation is charged before Upper Tertiary sedimentation,and suffered serious biodegradation and oxidation and rinsing,which provide a proof in another aspect that the crude oil of Upper Tertiary Shawan Formation of well Che89 is not from hydrocarbon source rock of Lower Tertiary.
