Table 2.
Composition and distribution of sedimentary facies types in the sub-oil-bearing Chang 82 formation and the oil-bearing Chang 9 formation.
| Oil-bearing formation | Sedimentary facies | Sedimentary subfacies | Main sedimentary microfacies | Distribution location in the study area |
|---|---|---|---|---|
| Chang 82 | Shallow delta | Shallow delta front | Underwater distributary channel | Entire area |
| Subaqueous levee | ||||
| Distributary bay | ||||
| Estuary bar | ||||
| Sand sheet | ||||
| Chang 9 | Braided river delta | Braided river delta front | Underwater distributary channel | Central part |
| Subaqueous levee | ||||
| Distributary bay | ||||
| Braided river delta plain | Distributary channel (braided channel) | Western part | ||
| Natural levee, rupture fan | ||||
| Diversion depressions, peat swamps | ||||
| Meandering river delta | Meandering river delta front | Underwater distributary channel | Eastern part | |
| Subaqueous levee | ||||
| Estuary dam | ||||
| Distributary bay | ||||
| Confluence area | Delta front | Underwater distributary channel | Southern part | |
| Distributary bay | ||||
| Subaqueous levee | ||||
| Sand sheet | ||||
| Estuary bar |