���������������ʮ������Ӫ��������Ĺ۲���ʾ���䷢����м�ң��ֲ�������ɽ�ҡ������ҡ�Ӫ����ɻ���Ϊ4 ����������: S7 ( Ӫ�Ķ�) ��S8 ( Ӫ����) ��S9 ( Ӫ����) ��S10 ( Ӫһ��) ����ӳӪ����ʱ�ں�ƽ�淢����4 �νϴ��ģ�ı仯���������������������ԽϺá�����7 ������ˮ�ͳ�������Ҫ����ˮ����; ����8 ���ڰ���ˮ����ر�Ե�������Է��������޺���������Ϊ����; ����9 �Ͳ���10 ������dzˮ�ͳ����������غ�ɫ���ҡ��Բ���9 Ϊ����������Ҫ�����ij�����ϵ����Ϊ�������޳�����ϵ�������޳�����ϵ�ͺ���������ϵ���ɽ�һ��ʶ�����������ǰԵ��������ǰԵ��������ƽԭ��dz���Ͱ������5 �����࣬ˮ�������ӵ����������������ӿڰӡ����塢ˮ���Ⱥ;�ˮ���19 ��΢�࣬�Է���ˮ���Ⱥ�ˮ�������ӵ�����Ϊ��ɫ��

The observation on drilling cores of Yingcheng Formation indicates that the main kinds of lithology are clastic rocks��interbeded with andesite lava and tuff in Shiwu oilfield��Lishu fault depression of Songliao Basin�� The Yingcheng Formation can be divided into 4 sequences in third order: S7 ( Ying 4) ��S8 ( Ying 3) ��S9 ( Ying 2) and S10 ( Ying 1) ��which developed and continued well in occurrence��reflecting 4 large-scale changes of lake level�� The Sequence 7 is a deep-water deposition��mainly developing underwater fan�� The Sequence 8 is a kind of semi-deep-water deposition in the edge of basin��mainly developing delta and fan-delta�� The Sequences 9 and 10 are shallow depositions��mainly developing brown mudstone�� The main depositional systems of Sequence 9 are the fan delta��the delta and lacustrine depositional systems�� Five kinds of subfacies including fan-delta front��delta front��delta plains��shallow lakes and semi-deep lake��and 19 kinds of micro-facies including underwater gravity channel��slump gravity flow��mouth bar��inter-bay��subaqueous fan and mud of still water��are further identified�� which are characterized by the subaqueous fan and underwater gravity channel in this area��