Sequence Framework and Reservoir Quality of Sha 1 Member inShahejie Formation, Qikou Sag

Key words: 
• sequence framework /
• sedimentary facies /
• diagenesis /
• reservoir quality /
• Sha 1 member /
• Qikou Sag

Abstract: There is a close relation between the sequence framework and reservoir quality, the different lithologic assemblage exists in different systems tracts which go through the different diageneisis, therefore, the reservoir quality in different systems tract is different. The relation among the sequence framework, diageneisis process, and reservoir quality has been paid much attention in this paper by the comprehensive study of geological and geophysical data. The Sha 1 Member of Tertiary in Qikou Sag could be divided into three sequences in the third class, which are consisted of LST, TST and HST. The sandstone and conglormarate from delta and subaqeous fan were developed in HST and has been in middle stage of diagenisis evolution with relative shallow depth, therefore, the reservoir quality of the sandstone and conglormarate is better than sandstone of LST. The reservoir quality in different systems tract is obvious different. Lastly, favorable and high quality reservoir has been forecasted according to the results of sequence framework, sedimentary facies and diagenesis of Sha1 member, that is, reservoir quality of Sha1 member in Qibei sub depression could be better than the quality in Qinan sub depression, and the reservoir quality of Sha 11 member could be better than the quality of Sha 12 member and Sha 13 member.