׼������س����ӵ���٪��ϵ�����ϵ�ز�ˮ�󻯶�����ϵͣ��� NaHCO 3 ˮ��Ϊ�������ݵز�ˮ��ѧ�ɷ�������������������ӱ���ϵ�����������������ۼ��Ĺ�ϵ���о�����: ���ӱ���ϵ�������Ե��ϱ������������ϲ�͹���Ե����Բ��ã�������¡��λ�ڹ���߲�λ����������Ϻã��ϲ������Ŀ������ݵ��������ϲ����ѵ��䵼��ϵ���Ƶ������ɲء�٪��ϵ�ز�ˮ�������ܹ��Ƚ�ǿ�ҵĴ�����ˮ��������ʹ�����ͷ���ˮϴ�������ã��γ��ֽ�����ij����Ͳء�٪��ϵ�ز�ˮ����Ժ��ڰ���ϵ���������������ۼ��ͱ��档

The formation water of Jurassic and Cretaceous in Chepaizi area of Junggar Basin is low TDS whole- ly and mainly is of the NaHCO 3 type�� Based on the chemical composition characteristics of the formation water in the Chepaizi area��the authors calculate the ion ratios to analyze the relationship with the oil and gas accumulation�� The research shows that the ion ratios have obviously differentiable characteristics in the north and south�� The south is on the edge of uplift which has adverse closure property while the north is on the palaeohigh which has good clo- sure property�� The oil and gas from Sikeshu sag of southern adjacent area were migrated to the north by petroleum migration pathways such as south faults�� The Jurassic formation water had suffered from more strong infiltration of atmospheric precipitation��which led to oxidation of early oil and formed the current heavy oil reservoir�� The closure property of the Jurassic formation water is better than that of Cretaceous��which favors oil and gas in accumulation and reservation��