Sandstone reservoir microscopic characteristics of braid delta of Hongtai area in Tuha Basin

Key words:  Tuha Basin  Hongtai area  braid delta  microscopic characteristics  diagenesis  pore structure

Abstract:

Based on the core observation and thin section analysis of 200 cores, the sandstone reservoir microscopic characteristics of braid delta of Hongtai area in Tuha Basin were investigated by image analysis system ( AxioVision4.0). The pore structure was classified into five kinds of A - E, and the pore structures of all the types were evaluated. The results show that the compositional maturity and the textural maturity of detrital component are low in this area，and the interstitial materials of detrital component are clay matrix material and carbonate cement. And the lithology in this area is feldspathic lithic arenite and litharenite. The diagenesis mainly includes compaction, cementation and metasomatosis，dissolution and solution. The deformation of ductile grain，carbonate cement，secondary origin quartz，carbonate alternation and corrosion are the common appearances. The analysis results of the parameters for the pore structure show that the reservoir properties of channel sand of delta plain is better than those of channel sand of delta front.