东胜气田锦66井区盒2+3段地层水特征及地质意义

Characteristics and geological significance of the formation water for 2+3^(th) member of Xiashihezi formation in Jin 66 well block of Dongsheng gas field

通过对东胜气田锦66井区盒2+3段地层水主要化学特征参数分析,揭示了锦66井区盒2+3段地层水的化学性质与气藏储层之间的内在联系。研究表明:东胜气田锦66井区盒2+3段正常地层水的判断标准为矿化度≥25000 mg/L、钠氯系数﹤0.4、钠钙系数﹤2.3、压裂液返排率≥55%;盒2+3段地层水为氯化钙水型,整体为高矿化度弱酸性盐水–卤水;储层封闭性良好,非常有利于天然气的富集保存;储层以次生孔隙为主,物性差异较大、连通性较差。

Through the main chemical characteristic parameters analysis of formation water for 2+3th member of Xiashihezi formation in Jin 66 well block of Dongsheng gas field,the internal relationship between the chemical properties of formation water and gas reservoirs is revealed.The results show that the judgment standard of the normal formation water for 2+3th member of Xiashihezi formation in Jin 66 well block is as the follows:the salinity is greater than 25 000 mg/L,the sodium chloride coefficient is less than 0.4,the sodium calcium coefficient is less than 2.3 and the fracturing fluid return rate is greater than 55%.The formation water is of calcium chloride water type,and as the whole,it is high salinity weak acid brine–brine.The reservoir is well sealed,which is beneficial to the accumulation and preservation of natural gas.The secondary porosity with characteristics of great physical differences and poor connectivity,is the main reservoir type.