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On the basis of strike-slip fault scale in the Qaidam Basin, the authors hold that the strike-slip fault can be graded into basin-scale, zone-scale, trap-scale and microscope-scale, the complicated strike-slip fault and relevant tectonic combination are related to tectonic movement and evolution, the authors make an analysis of the evolution age in this area, and pointed out that the strike-slip fault is extensional fault depression basin in Early Himalayan movement, reversal fault in Middle Himalayan movement and compressional strike-slip fault in Late Himalayan movement. Corresponding to the tectonic movements, three kinds of strike-slip fault (extensional faulted depression, depression and compressional strike-slip) were formed with different mechanical characteristics. Finally, the paper discusses how strike-slip fault impact trap formation, oil and gas transmission, and reservoir, and how such impacts are related to hydrocarbon accumulation, research on strike-slip fault play an important role in accumulation forming process, controlling the hydrocarbon accumulation, oil and gas distribution patterns.

In recent years, significant progress has been achieved in the field of deep exploration in the Yingxi area of the Qaidam Basin. The Eocene was characterized by mixed sediments in the lacustrine basin. The area consists of lacustrine carbonate, detrital material, and mud. All rocks contain numerous salt minerals. Via core observation, physical property analysis, capillary pressure tests, image logging, and field emission scanning electron microscopy, results reveal that the rocks contain a double porosity system. The first are fractures and salt mineral dissolution pores possessing a large pore radius, and the second are cracks between the salts and dolomite intercrystalline pores with a small pore radius. These two types of pores caused the double-platform feature with a lower narrow portion and upper wide portion on capillary pressure curves. Overall, the physical properties of the rocks are deficient, with low porosity-ultra-low permeability. Moreover, pores and throats are generally acceptable. Mineralogical composition analysis based on electronic probe shows that the rocks possess a high content of both silicon and aluminum, but low content of iron and manganese. The average FeO content in the dolomicrite is 1.322%, and that of MnO is 0.060%, both of which are lower than average Fe or Mn content in hydrothermal dolomite. It is believed that the dolomicrite possesses a penecontemporaneous metasomatic formation mechanism. The dolomitization process produces a large number of shrunken intercrystalline pores. These kinds of matrix pores, functioning as storage space, constitute an important support factor for the sustained and stable production of oil and gas in the study area.