According to its 13 lithologic microfacies

14 lithologic facies

7 sedimentary microfacies and the characteristics of 9 mudstone layers formed in lake transgression

Chang 6 member in Jing'an Oilfield could be divided into one parasequence series(PSS)

3 parasequences (PS

1

PS

2

PS

3

).In PS

1

the sedimentary microfacies varies from shallow lake or prodeltaic facies-frontal deltaic facies to subaqueous distributary channel facies

or from interbranch channel facies to deltaic plain distributary channel facies in ascendind order

reflecting lake transgression regression process.In PS

2

the microfacies varies from prodeltaic deltaic front facies to distal bar-river mouth bar facies and then subaqueous distributary channel facies

reflecting the parasequence development process of water getting shallower and shallower.ndistributarychannelfaciesina