摘要
Terrigenous clastic rock reservoir is discovered in the Paleogene Lulehe Formation at Kunbei oilfield,southwestern Qaidam Basin. Basing on well coring and logging data,sediment and reservoir characteristics of Lulehe Formation in Qie 16 block of Kunbei oilfield have been studied by means of the casting thin sections and scanning electron microscope. The result shows that two braided river delta facies sediments develop in Kunbei oilfield; rock types of the Lulehe Formation reservoir are relatively stable and the clastic rocks are mainly lithic feldspar sandstones mainly composed of granite,with low compositional maturity and rigid backbone. The content of matrix content is relatively high while cement is low. As a low-porosity and low-permeability reservoir,it is mostly controlled by sedimentary microfacies, matrix contents and diagenesis, such as compaction, cementation and dissolution, dominated by compaction. The reservoir pores are well developed with uniform distribution and good connectivity while the types of the pore are mainly primary intergranular pore. Combined with log responses character of the mainly reservoir and strata bound seismic amplitude attribute,the structural hights in the east side of well Q15 to well Q169 and in the southwestern part of well Q20 are believed to be the favorable aims for oil exploration.