Characteristics and genesis of clay minerals in the northern margin of the Qaidam Basin

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.

以便在 Qaidam 盆的北边缘开发适当水库保护措施并且改进它的油和煤气的恢复效率，从从 Qaidam 盆的北边缘的十一件泥土岩石样品的泥土矿物质的特征用X光检查衍射分析被调查，扫描电子显微镜( SEM )和精力光谱分析。主要的烃水库的克莱矿物质作文和分发特征，即从侏罗记和 Paleogene 鈥揘e ogene，被探索。我们分析了影响了这些属性的主要因素。结果证明在北边缘的主要泥土矿物质是绿泥石， kaolinite， illite，绿土和 illite/smectite inter-stratified 矿物质。Illite 是在这个区域的最广泛地散布的泥土矿物质。绿泥石主要在全部晚第三纪并且在 Paleogene 的浅地平线被发现。绿土在浅 Paleogene 鈥揘e ogene 被充实。在侏罗记有大量 kaolinite 和 illite/smectite inter-stratified 矿物质。在这个区域影响泥土矿物质的不同发展的主要因素是父母岩石，古气候和 paleowater 媒介条件的性质，成岩作用转变，构造并且地面条件。