Population genetics. Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure.
In the fluid-filled case, the wellbore is presumed to be full of either all liquid or gas which gets compressed as afterflow continues into the wellbore. The wellbore storage constant (C) is a function of the wellbore volume (Vw) and the wellbore fluid compressibility (cwb) as shown below: For a fluid-filled wellbore:
Viscosity is a measure of the resistance of a fluid to deformation under shear stress. It is commonly perceived as thickness, or resistance to pouring. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. Thus, water is thin, having a low viscosity, while vegetable oil is thick having a high viscosity.