In order to develop appropriate reservoir protection measures in the northern margin of the Qaidam Basin and improve its oil and gas recovery efficiency,characteristics of clay minerals from eleven clay rock samples f...In order to develop appropriate reservoir protection measures in the northern margin of the Qaidam Basin and improve its oil and gas recovery efficiency,characteristics of clay minerals from eleven clay rock samples from the northern margin of the Qaidam Basin were investigated using X-ray diffraction analysis,the Scanning Electron Microscope（SEM）and energy spectrum analysis.Clay mineral composition and distribution characteristics of the main hydrocarbon reservoirs,i.e.,from the Jurassic and Paleogene-Neogene,were explored.We analyzed the main factors which affected these attributes.The results show that the major clay minerals in the northern margin are chlorite,kaolinite,illite,smectite and illite/smectite inter-stratified minerals.Illite is the most widely spread clay mineral in this area. Chlorite is mainly found in the entire Neogene and in shallow horizons of the Paleogene.Smectite is enriched in the shallow Paleogene-Neogene.There are large amounts of kaolinite and illite/smectite inter-stratified minerals in the Jurassic.The major factors affecting the different development of clay minerals in the region are properties of parent rocks,paleoclimate and paleowater media conditions, diagenesis transformation,tectonic and terrain conditions.展开更多
The Qinghai-Xizang (Tibet) Plateau and the 'Sanjiang' area②, where are extensively developed theTethys-type marine Triassic sequences with Indosinian tectonic disturbance and magmatism, provide an impor-tant ...The Qinghai-Xizang (Tibet) Plateau and the 'Sanjiang' area②, where are extensively developed theTethys-type marine Triassic sequences with Indosinian tectonic disturbance and magmatism, provide an impor-tant region for the study of the tectonic evolution and the Indosinian movement of China as well as for thestudy of the boundary between Gondwana and Laurasia and the characteristics of the time-space distributionof the Tethys oceanic crust within the territory of China. Over a long period of time in the past, quite a numberof scholars made substantial studies and discussious from various viewpoints on the geotectonie and regionalgeological evolution of this region. Based on some new data obtained recently and the field observations by theauthor, and by using the plate tectonic theory, the author considers that there developed a Pacific-type (activetype) ancient continental margin bordering the Palaeo-Tethys ocean (or North Tethys ocean) in the south inLate Permian to Triassic times in the region of south-central Qinghai, northeastern Xizang (Tibet), western andsouthwestern Sichuan, and western Yunnan. Its characteristics basically represent the Indosinian tectonic evo-lution of this region.展开更多
基金provided by the National Petroleum and Gas Resources Strategic Area Selection Survey & Evaluation projects in 2005,is gratefully acknowledged.
文摘In order to develop appropriate reservoir protection measures in the northern margin of the Qaidam Basin and improve its oil and gas recovery efficiency,characteristics of clay minerals from eleven clay rock samples from the northern margin of the Qaidam Basin were investigated using X-ray diffraction analysis,the Scanning Electron Microscope（SEM）and energy spectrum analysis.Clay mineral composition and distribution characteristics of the main hydrocarbon reservoirs,i.e.,from the Jurassic and Paleogene-Neogene,were explored.We analyzed the main factors which affected these attributes.The results show that the major clay minerals in the northern margin are chlorite,kaolinite,illite,smectite and illite/smectite inter-stratified minerals.Illite is the most widely spread clay mineral in this area. Chlorite is mainly found in the entire Neogene and in shallow horizons of the Paleogene.Smectite is enriched in the shallow Paleogene-Neogene.There are large amounts of kaolinite and illite/smectite inter-stratified minerals in the Jurassic.The major factors affecting the different development of clay minerals in the region are properties of parent rocks,paleoclimate and paleowater media conditions, diagenesis transformation,tectonic and terrain conditions.
基金A subject of Project Nos.85001 and 851287 funded by the State National Science Foundation.
文摘The Qinghai-Xizang (Tibet) Plateau and the 'Sanjiang' area②, where are extensively developed theTethys-type marine Triassic sequences with Indosinian tectonic disturbance and magmatism, provide an impor-tant region for the study of the tectonic evolution and the Indosinian movement of China as well as for thestudy of the boundary between Gondwana and Laurasia and the characteristics of the time-space distributionof the Tethys oceanic crust within the territory of China. Over a long period of time in the past, quite a numberof scholars made substantial studies and discussious from various viewpoints on the geotectonie and regionalgeological evolution of this region. Based on some new data obtained recently and the field observations by theauthor, and by using the plate tectonic theory, the author considers that there developed a Pacific-type (activetype) ancient continental margin bordering the Palaeo-Tethys ocean (or North Tethys ocean) in the south inLate Permian to Triassic times in the region of south-central Qinghai, northeastern Xizang (Tibet), western andsouthwestern Sichuan, and western Yunnan. Its characteristics basically represent the Indosinian tectonic evo-lution of this region.
