Abstract: 252 activated water samples have been picked and analyzed. It is found that they are characterized by high salinity, high acti-vated coefficient,and NaHCO₃ formation water in early state of activation is mainly distributed along District 9 of Karamay oilfield-Wuerhe oilfield-Fengcheng oilfield-Mahu oilfield, with trace elements of boron (B), ammonium (NH⁴⁺), and abnormal high content of organic carbons. This area is just situated in zones where mantle is bulging and a great fault goes through in Junggar basin. In eastern part of the basin, there also exists a Tantle bulge zone”called W ucaiwan oil region in which much activated water occur. In the past, to evaluate subsurface occlu-sion property only depended upon the ratio of rNa/rCl of CaCl₂ formation water. Nowadays, we can even evaluate the subsurface occlusion property of NaHCO₃ water. Appearance of activated water implies the hopes for finding out hydrocarbon reservoirs, presuming if a light oil pool is found, and estimating the possibly formed period of a hydrocarbon reservoir.

Key words: Junggar basin, formation water, NaHCO₃ water type, CO₂, activation, boron (B), ammonium (NH⁴⁺)