Abstract:

Based on sedimentary facies research,  using all kinds of analysis data, the petrology, reservoir space and diagenesis of Chang 8 reservoir in Baibao oilfield have been studied in detail. The results show that compositional maturity is low and structural maturity is moderate, intergranular pore and feldspar dissolution pore are the main pore types, the pore throat is thin or tiny. According to authors’ method, four kinds of main diagenesis are quantitatively evaluated. The diagenesis is medium-intense compaction, medium-intense cementation, medium-intense metasomatism, medium erosion in the area. Finally, according to the research, four types of diagenetic reservoir facies are identified including mixed pore diagenetic reservoir facies with strong solution and weak cementation, compositional pore diagenetic reservoir facies with moderate compaction and moderate solution, residual pore diagenetic reservoir facies with strong compaction and moderate cementation, micropore diagenetic reservoir facies with strong compaction and strong cementation. The first diagenetic reservoir facies is the best for oil accumulation and seepage, the fourth diagenetic reservoir facies is resistant to oil accumulation and seepage.

Key words: Baibao oilfield, lithology, maturity, pore type, pore evolution, diagenetic reservoir facies