When the offset distance is smaller on the wellhead, the layer velocity obtained with straight line and the refraction line is matched with that of actual formation velocity.

当井口偏移距较小时，直线法和折线法求取的层速度和地层真速度吻合；

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Rapidly changing refraction due to turbulence along the line of sight affects different colors of light by different amounts and generally produces a twinkling effect for stars.

由于湍流而快速变化的折射在视线中会影响到光的不同颜色，这种影响也各不相同，一般会给恒星产生一种闪烁的效果。

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Based on the analysis of present methods for atmospheric refraction correction, a new correction model is put forward based on the refraction Angle of the line of sight.

本文在分析现有水准折光改正方法的基础上，导出了一种基于水准视线折光角的改正模型。

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