克拉玛依油区高矿化度重碳酸钠型水的发现与特征

DISCOVERY AND CHARACTERISTICS OF HIGH-MINERALIZED SODA-DICARBONATE-TYPED WATER IN KARAMAY OIL REGION

在准噶尔盆地西北缘克拉玛依油区的风城池田、玛北油田的石炭系、二叠系及三叠系下部发现了矿化度高达150g／L的NaHCO3型水（按苏林分类），是迄今为止准噶尔盆地地层水矿化度最高者，水化学特征首先是硼（B）含量高达1700～2300mg／L，是国内外文献中尚未见到的。其次是CO＋HCO含量非常高，占水中阴离子总量的56％～88％，CO2高达31～39g／L，HCO了高达14～36g／L，相应的Ca2+和Mg2+含量皆小于0．1g／L，与高矿化及NaHCO3型水同时产出的原油密度变化较大，为0．789～0．895g/cm3．此水压力高，沿断裂从内部上升与早期形成的CaCl2型水混合形成中局矿出应的Na2SO4型水，见于八区二叠系、三叠系油藏的古边水区．高矿化度NaHCO3型水的成因，推测是在地壳深部，由成因不明的高压力、高浓度的CO2气体进入水中形成的．根据发现点的分布，可能与深层潜伏的深断裂有关，并和轻质原油（密度＜0．84g／cm3）的分布带基本一致．

The NaHCO3-typed water with the degree of mineralization up to 150g/L which is most highly mine ralized formation water in the Junggar Basin so far is discovered in the Carboniferous, the Permian and the Lower Triassic strata of the Fengcheng oil Field and the North Karamay Oil Field in the Karamay oil region on the northwest edge of the Junggar Basin. The first chemical characteristic of water is high boron (B) content up to 1700-2300 mg/L which has not been reported at home and abroad. The second one is very high CO +HCO3 content which makes up 56%～88% of the total anion content in the water. Of which, the CO content is up to 31-39g/L, HCO3 content to 14～36g/L, and the re1evant Ca2- and Mg2-contents are all less than 0.1g/L. The crude oil produced simultaneously with high-mineralized NaHCO3-typed water has greater change with density of 0. 789～0 .895g/cm3. This high pressure water rises from within along faults and is mixed with early formed CaCl2-typed water to result in middle-high mineralized Na2SO4-typed water which is seen in the paleo-edge-water region of the Permian and Triassic oil accumula-tion in No. 8 area. The high-mineralized NaHCO3-typed water is inferred to generate when high pressure and high concentration CO2 gas of unknown genesis comes into water in the deep of the crust. The distri bution of discovery points suggests that it may have something to do with the deep buried faults and is con-sistent with the distribution of Iight crude oil (with density <0. 84g/cm3) on the whole.