柴达木盆地北缘冷湖三号构造油田水水化学特征

Hydrochemical Charateristics of Oilfield Waters in Lenghu No. 3 Structure Area of North Edge of Qaidam Basin

油田水是沉积盆地中的重要流体,通过柴达木盆地北缘冷湖三号构造油田水水化学分析,来深入理解该地区的水化学特征并探讨其成因。研究表明,冷湖三号构造油田水的矿化程度较低且以CaCl_2型水为主,硅酸盐的溶解是油田水中的K、Mg、B、Li等元素的重要来源,而油田水中F含量的异常高值很可能与区内断裂作用有关。油田水水化学特征系数分析结果指示,冷湖三号构造油田水的演化是在较好的封闭条件和还原环境下进行的。和柴达木盆地西部相比,研究区油田水主要成分的含量低于或远低于柴达木盆地西部,K、Li、B等元素均未达到矿床的边界品位,目前尚难以利用。

Oilfield water is an important fluid in sedimentary basin. Through hydrochemical analyses of oilfield waters collected from the Lenghu No. 3 Structure area in north Qaidam Basin,the hydrochemical characteristics of these waters were deeply understood and their genesis was discussed. Studies results show that the mineralization of oilfield waters in Lenghu No. 3 Structure are mainly CaCl_2 types. It is sepculated that the resolution of silicates is an important source for the elements of K,Mg,B,Li in oilfield water. Abnormally high contents of F in some oilfield waters are probably related with the existence of deep-seated faults in study area. Analyses of hydrochemical charateristic coefficients indicate that the evolution of oilfield waters in Lenghu No. 3 Structure were under well closed condition and reduing environment. Compared to main components of oilfield waters in western Qaidam Basin,those in Lenghu No. 3 Structure have lower or much lower values. The contents of the element K,Li,B are under the cut-off grade and nowaday it is hard to be utillized.