Lin_Dist_Inj(Prod)_Factor explanation

Could you Guys please help understand Lin_Dist_Inj_Factor and Lin_Dist_Prod_Factor feature?

Data description refers to figure 2 (which I place below for reference) but that does not explain it for me, unfortunately.

What are inj_x and f_x in the given formula?
What would be the formula for Lin_Dist_Inj_Factor?

The equation is a bit difficult to understand, but to spell out those variables more:

Lin_Dist_Inj_Factor - Injection weighted average distance factor from all injection points to the well.
Lin_Dist_Prod_Factor - Production weighted average distance factor from all production points to the well.

These variables weigh the volume (injection or production ) based on the physical proximity of injection wells to the producing well. We are unable to give you the inputs for these variables, which would have helped your question.