Abstract:

The HZ25-7 structure is one of the very important oil-bearing series find in deep Paleogene of Huizhou depression in Pearl River Mouth Basin in recent years, but because the lithology, source direction and depositional environment of this structure are complicate, it is difficult for further exploration and development. Focused on the Wenchang Formation and Enping Formation, this paper detailedly analyzes the characteristics of lithology and sedimentary structure of the study area using the high-resolution electric imaging data together with core data and conventional logging data. The result indicates that the objective interval is of braided river delta.The logging response characteristics of three sedimentary microfacies,i.e. braided channel, subaqueous distributary channel and mouth bar are established. The analysis of palaeocurrent direction shows that the source is migrated from south to north for a long time. Then the regional distribution of microfacies of the key sandbody is mapped based on the above results and the regional geological background,indicating the distribution direction of the favorable reservoir in the study area.

Key words: Paleogene, imaging logging, sedimentary structure, sedimentary microfacies, paleocurrent direction, Pearl River Mouth Basin