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.