某油田采油井在下Ф73.02 mm×5.51 mm N80加厚油管过程中,发现一根加厚油管过渡区位置出现裂纹,通过对事故油管管体进行力学性能及化学成分试验、断口宏观形貌分析、断口电镜扫描分析,对加厚油管断裂原因进行综合分析。结果表明:...某油田采油井在下Ф73.02 mm×5.51 mm N80加厚油管过程中,发现一根加厚油管过渡区位置出现裂纹,通过对事故油管管体进行力学性能及化学成分试验、断口宏观形貌分析、断口电镜扫描分析,对加厚油管断裂原因进行综合分析。结果表明:该加厚油管的断裂形式为脆断,油管镦粗过程中温度控制不当,造成油管"过烧",形成夹渣物残留在加厚油管过渡区,产生脆性裂纹源,下井过程中油管再次受到拉伸载荷,使裂纹源进一步扩展,最终油管发生断裂。展开更多
The Quaternary sediments in the Yangtze delta are loose and lack precise stratification marks in the lithology. Moreover, due to the limitations of dating methods, it is difficult for Quaternary cores to deliver accur...The Quaternary sediments in the Yangtze delta are loose and lack precise stratification marks in the lithology. Moreover, due to the limitations of dating methods, it is difficult for Quaternary cores to deliver accurate age constraints. Thus, it is a challenge to establish the Quaternary stratigraphic framework. Gravity core LZK1 was drilled on Hengsha Island, Shanghai, in the Yangtze delta, in 2012. The core was terminated at 403.83 m below the local land surface, the uppermost 291.2 m comprising a thick sequence of Quaternary sediments. This study investigated the stratigraphic subdivision and paleoenvironmental change of the Quaternary sediments. From bottom to top, the Quaternary stratigraphic sequence can be subdivided into the lower Pleistocene Anting Formation, Middle Pleistocene Jiading Formation, Upper Pleistocene Chuansha Formation and Nanhui Formation, Holocene Loutang Formation, Shanghai Formation, and Rudong Formation. According to this study, the Hengsha Island area was dominated by a freshwater lacustrine environment during the early Pleistocene, an alternation of shallow lake and shore lake environment during the Middle Pleistocene, a delta plain to lagoonal environment during the early Upper Pleistocene, a fluvial channel to floodplain environment from the LGM(Last Glacial Maximum) to the end of the Upper Pleistocene, and a delta environment during the Holocene.展开更多
Eupatorium adenophorum is a noxious invasive weed that is distributed throughout subtropical areas worldwide.Enemy release may be at least one of the reasons underlying its success as an invader.In this study,we obser...Eupatorium adenophorum is a noxious invasive weed that is distributed throughout subtropical areas worldwide.Enemy release may be at least one of the reasons underlying its success as an invader.In this study,we observed damage to the epidermis,cortex,phloem,cambium,and xylem tissues of roots and stems around the root collar of E.adenophorum growing in an experimental field in Yunnan Province,southwest China.The damage was caused by Dorylus orientalis,a polyphagous ant feeding on the weed and resulted in the death of the plants by interrupting nutrient exchange between shoots and roots.This ant showed selectivity for the invader to some extent.The finding of D.orientalis and other native enemies indicate that E.adenophorum may gradually naturalize in introduced landscapes.In addition,this ant may have potential for use as a biocontrol agent against the invader.展开更多
Foliated garnet-bearing granite,usually associated with high pressure and ultrahigh-pressure(UHP) metamophic rocks,is a particular rock-type extensively exposed in the Mesozoic Dabie-Sulu orogenic belt of China.This s...Foliated garnet-bearing granite,usually associated with high pressure and ultrahigh-pressure(UHP) metamophic rocks,is a particular rock-type extensively exposed in the Mesozoic Dabie-Sulu orogenic belt of China.This study focuses on deformation features and SHRIMP zircon dating of foliated garnet granite in a high-pressure metamorphic unit from Huwan,western Dabie Mountains in order to resolve discrepancies in current versions of its petrogenesis and structural evolution.SHRIMP dating reveals a zircon age of 762 ± 15 Ma(MSWD=1.7) for Huwan granites,representing the Middle to Late Neoproterozoic age of intrusion and crystallization.Field and microstructural studies show that the Huwan granite body underwent multiple-stage deformation.The deformation was manifested by an early stage of rootless folding and imposition of relict foliation(S1);an Indosinian main stage marked by imposition of north-dipping penetrative gneissosity(S2) and development of ductile shear zones under NNE-SSW directed compression;and a final Indosinian stage of southward thrusting of the Huwan high-pressure unit.Shallow level extension prevailed after the Late Triassic,giving rise to south-dipping thrust faults and north-dipping normal faults.展开更多
文摘某油田采油井在下Ф73.02 mm×5.51 mm N80加厚油管过程中,发现一根加厚油管过渡区位置出现裂纹,通过对事故油管管体进行力学性能及化学成分试验、断口宏观形貌分析、断口电镜扫描分析,对加厚油管断裂原因进行综合分析。结果表明:该加厚油管的断裂形式为脆断,油管镦粗过程中温度控制不当,造成油管"过烧",形成夹渣物残留在加厚油管过渡区,产生脆性裂纹源,下井过程中油管再次受到拉伸载荷,使裂纹源进一步扩展,最终油管发生断裂。
基金funded by the Geological Survey of China(Nos.DD20190370,DD20160345-07)the National Natural Science Foundation(No.40902049)。
文摘The Quaternary sediments in the Yangtze delta are loose and lack precise stratification marks in the lithology. Moreover, due to the limitations of dating methods, it is difficult for Quaternary cores to deliver accurate age constraints. Thus, it is a challenge to establish the Quaternary stratigraphic framework. Gravity core LZK1 was drilled on Hengsha Island, Shanghai, in the Yangtze delta, in 2012. The core was terminated at 403.83 m below the local land surface, the uppermost 291.2 m comprising a thick sequence of Quaternary sediments. This study investigated the stratigraphic subdivision and paleoenvironmental change of the Quaternary sediments. From bottom to top, the Quaternary stratigraphic sequence can be subdivided into the lower Pleistocene Anting Formation, Middle Pleistocene Jiading Formation, Upper Pleistocene Chuansha Formation and Nanhui Formation, Holocene Loutang Formation, Shanghai Formation, and Rudong Formation. According to this study, the Hengsha Island area was dominated by a freshwater lacustrine environment during the early Pleistocene, an alternation of shallow lake and shore lake environment during the Middle Pleistocene, a delta plain to lagoonal environment during the early Upper Pleistocene, a fluvial channel to floodplain environment from the LGM(Last Glacial Maximum) to the end of the Upper Pleistocene, and a delta environment during the Holocene.
基金supported by the National Natural Science Foundation of China(30830027 and 30670394)Applied Basic Study Project of Yunnan Province(2007C107M)the National Key Project of Scientific and Technical Supporting Programs(2006BAD08A17)
文摘Eupatorium adenophorum is a noxious invasive weed that is distributed throughout subtropical areas worldwide.Enemy release may be at least one of the reasons underlying its success as an invader.In this study,we observed damage to the epidermis,cortex,phloem,cambium,and xylem tissues of roots and stems around the root collar of E.adenophorum growing in an experimental field in Yunnan Province,southwest China.The damage was caused by Dorylus orientalis,a polyphagous ant feeding on the weed and resulted in the death of the plants by interrupting nutrient exchange between shoots and roots.This ant showed selectivity for the invader to some extent.The finding of D.orientalis and other native enemies indicate that E.adenophorum may gradually naturalize in introduced landscapes.In addition,this ant may have potential for use as a biocontrol agent against the invader.
基金Supported by the National Natural Science Foundation of China (Grant Nos.40802046 and 40334037)the Project of Science & Technology Research and Development from Sinopec (Grant No.P02009)
文摘Foliated garnet-bearing granite,usually associated with high pressure and ultrahigh-pressure(UHP) metamophic rocks,is a particular rock-type extensively exposed in the Mesozoic Dabie-Sulu orogenic belt of China.This study focuses on deformation features and SHRIMP zircon dating of foliated garnet granite in a high-pressure metamorphic unit from Huwan,western Dabie Mountains in order to resolve discrepancies in current versions of its petrogenesis and structural evolution.SHRIMP dating reveals a zircon age of 762 ± 15 Ma(MSWD=1.7) for Huwan granites,representing the Middle to Late Neoproterozoic age of intrusion and crystallization.Field and microstructural studies show that the Huwan granite body underwent multiple-stage deformation.The deformation was manifested by an early stage of rootless folding and imposition of relict foliation(S1);an Indosinian main stage marked by imposition of north-dipping penetrative gneissosity(S2) and development of ductile shear zones under NNE-SSW directed compression;and a final Indosinian stage of southward thrusting of the Huwan high-pressure unit.Shallow level extension prevailed after the Late Triassic,giving rise to south-dipping thrust faults and north-dipping normal faults.
