SHRIMP U-Pb zircon 207 Pb/206 Pb ages were obtained from two drill cores from the basement of the Ordos Basin.A garnet-sillimanite-biotite-plagioclase gneiss(QI1-1) from the western Ordos Basin basement yielded an ave...SHRIMP U-Pb zircon 207 Pb/206 Pb ages were obtained from two drill cores from the basement of the Ordos Basin.A garnet-sillimanite-biotite-plagioclase gneiss(QI1-1) from the western Ordos Basin basement yielded an average age of 2031 10 Ma.Based on the mineral assemblages,the source material of the gneiss is speculated to be pelitic-felsic system.A gneissic two-mica granite(Long1-1) from the eastern Ordos Basin basement yielded an average age of 2035 10 Ma.The zircons from both samples exhibit magmatic growth pattern.The shapes of the zircons suggest that the zircons should crystallize from a granitic of felsic volcanic terrain.The ages and the characters of zircons are consisitent with the other researches in the Ordos Basin and indicate that the basement of the Ordos Basin had experienced an intensive magmatic epsode during the late Paleoproterozoic period.The date from this study suggest the possible existences of a Paleoproterozoic mobile tectonic belt in the region.The reconstruction of such a belt is critical for understanding the tectonomagmatic evolution of the western block of the North China Craton.展开更多
It is becoming an important controlling factor of gas exploration and exploitation in the east part of Sulige gas field in the Ordos Basin where the reservoir of main gas formations is tight sandstones. Employing expe...It is becoming an important controlling factor of gas exploration and exploitation in the east part of Sulige gas field in the Ordos Basin where the reservoir of main gas formations is tight sandstones. Employing experimental methods of slice identification, casting slice, scan electron microscope, and X-ray diffrac- tions, we studied the characteristics of petrology and diagenesis on reservoirs in Shanl section of Shanxi formation and He8 section of Shihezi formation of the Permian system in the East II part of Sulige gas field. The results include： （1） the main sandstones in these areas are dominated by lithic sandstone and litbic silicarenite with low grade of maturity; （2） the diagenesis of sandstone in these areas mainly include compaction, cementation, corrosion and alteration. Conclusions are as follows： （1） the diagenetic stage reached period B of the middle diagenetic stage; （2） the early diagenetic compaction is one of the main factors to decreasing porosity; （3） the secondary pores formed by corrosion in acidity medium con- ditions in period A of the middle diagenetic stage can distinctly ameliorate the poor reservoir capability of sandstone and, （4） cementation in period B of the middle diagenetic stage is the most important factor leading; to poor physical property of sandstone reservoirs.展开更多
基金supported by the National Basic Research Program of China (2012CB416604 and 2012CB416603)the National Natural Science Foundation of China (91114204)
文摘SHRIMP U-Pb zircon 207 Pb/206 Pb ages were obtained from two drill cores from the basement of the Ordos Basin.A garnet-sillimanite-biotite-plagioclase gneiss(QI1-1) from the western Ordos Basin basement yielded an average age of 2031 10 Ma.Based on the mineral assemblages,the source material of the gneiss is speculated to be pelitic-felsic system.A gneissic two-mica granite(Long1-1) from the eastern Ordos Basin basement yielded an average age of 2035 10 Ma.The zircons from both samples exhibit magmatic growth pattern.The shapes of the zircons suggest that the zircons should crystallize from a granitic of felsic volcanic terrain.The ages and the characters of zircons are consisitent with the other researches in the Ordos Basin and indicate that the basement of the Ordos Basin had experienced an intensive magmatic epsode during the late Paleoproterozoic period.The date from this study suggest the possible existences of a Paleoproterozoic mobile tectonic belt in the region.The reconstruction of such a belt is critical for understanding the tectonomagmatic evolution of the western block of the North China Craton.
基金supported by the Science Development Project of Shandong Province (No.2009GG20001021-07)the Open Fund of Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Minerals (No. DMSM200803)the SDUST Research Fund (No.2010KYTD103)
文摘It is becoming an important controlling factor of gas exploration and exploitation in the east part of Sulige gas field in the Ordos Basin where the reservoir of main gas formations is tight sandstones. Employing experimental methods of slice identification, casting slice, scan electron microscope, and X-ray diffrac- tions, we studied the characteristics of petrology and diagenesis on reservoirs in Shanl section of Shanxi formation and He8 section of Shihezi formation of the Permian system in the East II part of Sulige gas field. The results include： （1） the main sandstones in these areas are dominated by lithic sandstone and litbic silicarenite with low grade of maturity; （2） the diagenesis of sandstone in these areas mainly include compaction, cementation, corrosion and alteration. Conclusions are as follows： （1） the diagenetic stage reached period B of the middle diagenetic stage; （2） the early diagenetic compaction is one of the main factors to decreasing porosity; （3） the secondary pores formed by corrosion in acidity medium con- ditions in period A of the middle diagenetic stage can distinctly ameliorate the poor reservoir capability of sandstone and, （4） cementation in period B of the middle diagenetic stage is the most important factor leading; to poor physical property of sandstone reservoirs.
