superposition derivative应该怎么理解？ [复制链接]

Though the pressure dependent leakoff analysis resulted in
a means to estimate the pressure dependent leakoff function,
the method could not be validated because of the lack of a
suitable fracture design model capable of using this function
to calculate fracture geometry.In this study the method is
validated by a fully 3D fracture geometry model. A
diagnostic superposition derivative of the analytical G-
function is shown to uniquely distinguish between pressure
dependent leakoff,fracture height changes,and tip extension
and recession.Use of the superposition derivative to analyze
fracture treating pressure behavior during pumping has been
presented by Ayoub,et al .The correct application of pressure
dependent leakoff to fracture geometry calculations
substantially alters the resulting fracture size and fluid
efficiency.Accurate modeling of this effect can reduce the
occurrence of premature screenouts,which are common in the
case of pressure dependent leakoff,and improve the overall
treatment design.

是叠加导数。
我查了一篇文献，对照中英文摘要可以得出结论。附：论文，请参考。

是呀，这里superposition derivative 毫无争议就是“叠加导数”之意。