鄂尔多斯盆地中部奥陶系地层水有机组分特征

毛细管等速电泳法分析结果表明 :鄂尔多斯盆地中部气田奥陶系地层水中有机酸总量分布范围为9.17～94.49mg/L(主要在20～50mg/L之间),明显高于石炭二叠系地层水中有机酸总量,但两者都具有乙酸 甲酸>丙酸>丁酸的组成特征;烷基酚总含量为0.57～4.73mg/L,平均1.77mg/L,其中1.0mg/L以下的占47.06%,1.0～3.0mg/L的占35.29%,>3.0mg/L的占17.65%。平面上,中部气田马家沟组地层水中有机酸和苯酚含量分布均呈现非均质性,分别出现若干个高值区(45mg/L和>2.0mg/L),这些高值区与中部气田天然气藏分布富集区基合吻合。

CHARACTERISTICSOFORGANIC COMPOSITIONS IN FORMATION WATERS FROM CENTRAL ORDOS BASIN

Isotachophoresis result indicates that the total organic acids concentration of Ordovician formation waters range from 9.17mg/l to 94.49mg/l and are obviously higher than those of Permo Carboniferous formation waters.But both of them have the same composition characteristics of acetic acidformic acid>propanoic acid>butanoic acid.The total alkyl phenol contents of Ordovician formation water range from 0.57mg/l to 4.73mg/l,and the average concentration is 1.77mg/l.Among the samples of phenol detection,47.06% samples are less than 1.0mg/l,and 35.29% samples are 1.0～3.0mg/l,and only 17.65% samples are more than 3.0mg/l.The concentration distribution of organic acids and phenols in the Majiagou formation waters occurs obvious heterogeneity.There are several higher organic acids and phenols concentration areas in the central part of Ordos Basin.High organic acid and phenol concentration areas of formation water(organic acids>45mg/l and phenols>2.0mg/l) are consistent with natureal gas reservoir enrichment areas in the central part of Ordos Basin.