Research On Diagenesis Of The Youshashan Formation In Yingdong Areas,Qaidam Basin

The Youshashan formation occurrence a lot of oil. The diagenesis of this formation hadn't studied. So,we should conduct in-depth study of sandstone diagenesis of this Areas. Using the microscope,the scanning electronic microscope,X-ray diffraction, and investigating a large amout of core data. We studied the petrologic feature, and analysis of the diagenetic types and features, then predicted the diagenetic stages and diagenetic facies of reservoir stratum.then studying secondary pore of this stratum.The sediments are mainly derived form Aral area, but in the south of this area the sediments are partly form Qimantage Mountain.The delta deposit and shallow lacustrine deposits are large distributed in the Yingdong formation.The mainly lithological of N22 are Sandstones and siltstones, lithic sandstone and arkose. The rock types of N21 are mostly arkose or lithic arkose sandstone.The main diagenesis type of Youshashan reservoir are the mechanical compression,cementation and dissolution.According to the analysis of diagenesis,the diagenetic stage mainly in early diagenesis, then entered in the middle diagenetic stage. The reservoir stratum has six lithogenous phase, such as weak cemented quicksand layer and weak compaction layer. The main reservoir space of the Youshashan formation are primary pore space and secondary pore space.The secondary pore are the most important reservoir space of deep formation. And the dissolution improve the secondary pore space.