准噶尔盆地腹部及南缘水化学纵向变化规律

LONGITUDINAL CHANGING REGULARITY OF HYDROCHEMISTRY FOR THE SOUTHERN EDGE AND HINTERLAND OF THE JUNGGAR BASIN

纵向水动力条件的变迁会对地层流体运移及聚集产生很重要的影响[1 ] 。水动力较弱、相对较滞流的环境有利于油气的保存 ;反之 ,水动力较强、相对较开放的环境则不利于油气的保存。文中利用地层水之矿化度、水型、钠氯比值及脱硫系数分别对准噶尔盆地腹部及南缘 (全区 )以及彩南地区和石西地区的水化学剖面类型进行了分析。结果表明 :①全区整体上表现了正向型水化学剖面特征 ,但个别地区存在反向型剖面及多向型剖面 ;②水动力相对较弱的深部地层也存在水动力相对较强的区域同时水动力相对较强的浅部地层也存在水动力相对较弱的地区 ,这有利于油气的保存 ;③无论是正向型水化学剖面还是反向型及多向型水化学剖面 ,只要地层水矿化度高且剖面变化较缓 ,则油气保存较好 ,若剖面变化剧烈 ,则油气保存不好。

WT5BZ]The change of longitudinal hydrodynamicconditions can have great effects on the migration and accumulation of formation liquid. The relatively stagnant environment with weaker hydrodynamic force is advantageous to the preservation of gas and oil. On the contrary, the relatively open environment with stronger hydrodynamic force is disadvantageous to the preservation of gas and oil. In this paper, the hydrochemical section types of Cainan area and Shixi area as well as the hinterland and southern edge of the Junggar Basin are analysed using formation waters salinity, water type, ratio of Na + and Cl -, and coefficient of desulfurization. The result reveals that the characteristics of positive type hydrochemical sections are shown in whole area, but reverse type and multi type sections do exist in some regions; there exists regions with stronger hydrodynamic force in deep strata with weaker hydrodynamic force and exists regions with weaker hydrodynamic force in shallow strata with stronger hydrodynamic force, and this is advantageous to the preservation of gas and oil; either positive type or reverse type or multi type hydrochemical sections, the preservation of gas and oil will be better provided the salinity of formation water is high and the change of sections is slower, otherwise the preservation of gas and oil will be bad if the change of sections is strong. [WT5HZ]