Two types of sedimentary facies(bioherm and organic bank) are developed in Liuhua 11-1 oilfield.They can be subdivided into 6 microfacies

including coralgal reef

coral reef

coralgal-coral reef

foraminiferal bank

bioclastic bank and coralgal debris-foraminiferal bank.Core observation and thin section analysis indicate that the diagenesis of reef complex in sea floor diagenetic environment

fresh water diagenetic environment and regional underground water-buried diagenetic environment include cohesion

dissolution

cementation

compaction-pressure solution

recrystallization

dolomitization and "chalkification"

etc.Based on the results of sedimentary facies analysis and the effects of various stages of diagenesis on poroperm characteristics of reservoirs

the sedimentary-diagenetic evolution of reef limestone reservoirs are divided into 8 periods

i.e.the early reef formation

early exposure-dissolution

late reef formation

middle exposure-dissolution

early reservoiring

late dissolution

late reservoiring and regional groundwater dissolution periods.This unique evolution pattern constitutes vertically 8-layer reservoir architecture

including the alternating of 4 high porous and permeable layers and 4 medium-low porous and permeable layers.Cementation is considered a major diagenetic factor in the 4 medium-low porous and permeable layers

namely layers A

B

2

C and E

which are relatively tight and have widely developed intercalations.The layers B

1

B

3

and D

being in percolation environment

have been turned into high porous and permeable layers through dissolution

while the high porous and permeable layer F formed by further dissolution of regional groundwater is an aquifer.