Analysis of the Main Controlling Factors on the Formation of Clastic Reservoirs in the Southwestern Area of the Qaidam Basin

Key words: 
• clastic reservoir /
• main controlling factors /
• Qaidam basin

Abstract: Based on a great deal of analytical data of rock andm ineral, discussed. the controlling factors on clastic rock reservoir property in the southwest area of the Qaidam basin are the sedimentary environment, lithological characteristics, buried history, unusual high fluid pressure, salt lake environmentweremain factors deciding reservoir diagenetic evolution and reservoir property. The widely developed sandstones of the shore sand platform, the delta plain and delta front are a basic condition for the development of excellent reservoirs. The content and size of the plastic grains in the reservoir clasts are important factors controlling the reservoir property. Diageneses are a crucial factor of reservoir property, in wh ich consolidation heavily a ffected reservoir property, cementation was on ly an important controlling factor influencing reservoir property in the partial area and the in fluence of dissolutionwasweak. Consolidation of reservoir is controlled by four factors,.i e., lithological haracteristics, strength of d iagenetic cementation, buried h istory, and strata flu id pressure. L ithologywas reflected by the change of the content of plastic rock clasts with grain size and different anti-pressure of reservoirwith different grain size. Development of diagenetic cements weakened consolidation of reservoir, buried history differed reservoir property and h igh fluid pressure effectively restrained consolidation.