柴达木盆地盐湖卤水层给水度分布变化特征

选择柴达木盆地马海盐湖作为研究对象,在研究区布置给水度采样点11处,采样深度1.61~148.5 m,采集给水度样品75件。结合研究区以往37处采样点的72个测试数据,共计取得48处采样点145个测试数据。根据给水度实测数据,采用数理统计方法分析了柴达木盆地马海盐湖卤水层给水度分布变化。其主要特征表现为：① 给水度在水平方向上表现出较大的差异性,卤水层W_Ⅰ至W_Ⅴ的给水度分别介于0~0.263 5、0.009 4~0.209 9、0~0.277 8、0.006 2~0.135 9、0~0.107 7。在采样点MHK-022~MHK-026处,各卤水层给水度值较小,均小于0.06。在盐湖东北部,各卤水层给水度值较大,均大于0.08。② 给水度在垂直方向上受地层静压力的影响随着深度的增加而减小,上部卤水层W_Ⅰ的给水度均值为0.105,下部卤水层W_Ⅴ的给水度均值已降至0.038 7,不足卤水层W_Ⅰ给水度均值的40%。③ 给水度在垂直方向上还表现出旋回性的变化特征,这种沉积旋回的出现可能是对成盐期间气候波动的反映。

Distribution and Variation Characteristics of Specific Yield in Brine Aquifer of the Saline Lake in Qaidam Basin

Select the Mahai Saline Lake in Qaidam Basin as an object of study. A total of 75 specific yield samples were collected from 11 sampling points in the research area, and the depth range is 1.61-148.5 m. The previous testing data of 72 specific yield samples were collected from 37 sampling points in the research area were obtained. We totally got 145 specific yield samples from 48 sampling points. According to the measured specific yield data, adopting mathematical statistics methods to analyze the qaidam basin mohair salt lake brine formations, distribution of water level changes. The specific yield in brine aquifer characteristics of distribution and variation of the saline lake in Qaidam Basin is studied by statistical analysis. It is found that: 1) There are larger difference of specific yield in the horizontal direction. The data of W_Ⅰ to W_Ⅴ brine aquifer are between 0-0.263 5, 0.009 4-0.209 9, 0.006 2-0.135 9, 0.006 2-0.135 9, 0-0.107 7. The specific yield of different brine aquifers have smaller values in the sample point MHK-022 to MHK-026, and the average is less than 0.06. While in the northeast of the salt lake, the specific yield of different brine aquifers have bigger values and the average is greater than 0.08. 2) Specific yield in the vertical direction affected by the hydrostatic pressure of strata. With the increase of the depth the specific yield were decreases. 3) Specific yield in the vertical direction also shows cyclicity change characteristics. The emergence of the depositional cycle may be right to reflect climate fluctuations during the period of the salt deposits.