The Mosuowan area in the Junggar Basin is surrounded by oil source depressions and is characterized by abundant oil and gas resources.Based on a clear understanding of the reservoir’s basic characteristics,an in-dept...The Mosuowan area in the Junggar Basin is surrounded by oil source depressions and is characterized by abundant oil and gas resources.Based on a clear understanding of the reservoir’s basic characteristics,an in-depth analysis of the reservoir’s four relationships was conducted.The primary lithologies of the first section of the Sangonghe Formation reservoir include fine sandstone and mediumfine sandstone.Oil leaching is predominantly observed in medium-fine sandstone,whereas fluorescence is more common in fine sandstone.The average porosity and permeability are 10.2%and 2.18 mD,respectively,indicating the presence of low to ultra-low porosity and permeability reservoirs.Among the lithologies,unequal-grained sandstone exhibits the best physical properties,followed by medium-fine sandstone.The oil content shows a negative correlation with both acoustic wave travel time and resistivity.The reservoir characteristics indicate that coarser lithologic grain sizes generally correspond to better physical properties,and better physical properties are associated with higher oil content grades.Clarifying the four relationships of the reservoir enhances the scientific rigor and reliability of reservoir evaluation and provides fundamental theoretical support for the efficient development of oil and gas resources.展开更多
The Chepaizi-Mosuowan paleo-uplift is a large-scale uplift stretching across the Junggar Basin formed during the Yanshanian. It has experienced four evolutionary stages: the initial forming stage (J1), the intense dev...The Chepaizi-Mosuowan paleo-uplift is a large-scale uplift stretching across the Junggar Basin formed during the Yanshanian. It has experienced four evolutionary stages: the initial forming stage (J1), the intense development stage (J2+3), the waning and burial stage (K-E), and the tilting and extinction stage (N-Q). The most intense period of activities is the Middle Jurassic. Dur-ing the Early Jurassic, the Chepaizi-Mosuowan paleo-structure was a low amplitude uplift. Because of the subsequent strong uplifting during Middle-Late Jurassic, the Middle and Upper Jurassic were eroded. With the evolution of the Chepaizi-Mosuowan paleo-uplift, the sedimentary pattern of the basin changed, and the paleo-uplift separated the northern depositional systems from those in the south side. As a result, the basin tectonics controlled the distribution and evolution of the depositional systems. During Early Jurassic, while the paleo-uplift was low, its controlling effect on depositional systems was limited and sediments coming from the northwest could reach the central and southern parts of the basin. With the strong uplifting of the Chepaizi-Mosuowan paleo-structure during Middle-Late Jurassic, sediments from the northwest provenance could only deposit in the northern graben of the paleo-uplift. The intense erosion of the Middle-Upper Jurassic also changed the former sedimentary center of the basin into a source area, supplying sediments for grabens on both sides of the paleo-uplift. In the Cretaceous, regional subsidence caused the paleo-uplift to be buried again and subsequently sediments accumulated on top of it. The depositional facies are dominated by fluvial in the Early Cretaceous and shallow lacustrine to deltaic in the Late Cretaceous. In the history of the long-lasting development of this paleo-uplift, large-scale erosions of the paleohigh not only provided sufficient sediments to the center of the Junggar Basin, but also created favorable conditions for the formation of various subtle traps such as lithologic and stratigraphic traps.展开更多
文摘The Mosuowan area in the Junggar Basin is surrounded by oil source depressions and is characterized by abundant oil and gas resources.Based on a clear understanding of the reservoir’s basic characteristics,an in-depth analysis of the reservoir’s four relationships was conducted.The primary lithologies of the first section of the Sangonghe Formation reservoir include fine sandstone and mediumfine sandstone.Oil leaching is predominantly observed in medium-fine sandstone,whereas fluorescence is more common in fine sandstone.The average porosity and permeability are 10.2%and 2.18 mD,respectively,indicating the presence of low to ultra-low porosity and permeability reservoirs.Among the lithologies,unequal-grained sandstone exhibits the best physical properties,followed by medium-fine sandstone.The oil content shows a negative correlation with both acoustic wave travel time and resistivity.The reservoir characteristics indicate that coarser lithologic grain sizes generally correspond to better physical properties,and better physical properties are associated with higher oil content grades.Clarifying the four relationships of the reservoir enhances the scientific rigor and reliability of reservoir evaluation and provides fundamental theoretical support for the efficient development of oil and gas resources.
基金supported by National Basic Research Program of China (Grant No. 2006CB202302).
文摘The Chepaizi-Mosuowan paleo-uplift is a large-scale uplift stretching across the Junggar Basin formed during the Yanshanian. It has experienced four evolutionary stages: the initial forming stage (J1), the intense development stage (J2+3), the waning and burial stage (K-E), and the tilting and extinction stage (N-Q). The most intense period of activities is the Middle Jurassic. Dur-ing the Early Jurassic, the Chepaizi-Mosuowan paleo-structure was a low amplitude uplift. Because of the subsequent strong uplifting during Middle-Late Jurassic, the Middle and Upper Jurassic were eroded. With the evolution of the Chepaizi-Mosuowan paleo-uplift, the sedimentary pattern of the basin changed, and the paleo-uplift separated the northern depositional systems from those in the south side. As a result, the basin tectonics controlled the distribution and evolution of the depositional systems. During Early Jurassic, while the paleo-uplift was low, its controlling effect on depositional systems was limited and sediments coming from the northwest could reach the central and southern parts of the basin. With the strong uplifting of the Chepaizi-Mosuowan paleo-structure during Middle-Late Jurassic, sediments from the northwest provenance could only deposit in the northern graben of the paleo-uplift. The intense erosion of the Middle-Upper Jurassic also changed the former sedimentary center of the basin into a source area, supplying sediments for grabens on both sides of the paleo-uplift. In the Cretaceous, regional subsidence caused the paleo-uplift to be buried again and subsequently sediments accumulated on top of it. The depositional facies are dominated by fluvial in the Early Cretaceous and shallow lacustrine to deltaic in the Late Cretaceous. In the history of the long-lasting development of this paleo-uplift, large-scale erosions of the paleohigh not only provided sufficient sediments to the center of the Junggar Basin, but also created favorable conditions for the formation of various subtle traps such as lithologic and stratigraphic traps.
