If you represent the well by a DF plus a WellBC at the lowest node with an injection (negative algebraic sign for the rate), a forced upward flow direction will inevitably occur. In contrast, if you extract water (positive algebraic sign for the rate), a downward directed flow direction will be triggered. DF act as preferential pathways for the groundwater flow induced by highly conductive material along the trace. In the standard implementation, DF's are perfectly hydraulically connected with the surrounding void space of the porous medium. If you want to have multiple screens along the trace of DF's I suggest to use either arbitrary node paths (http://www.feflow.info/html/help71/feflow/mainpage.htm#rhhlterm=arbitrary&rhsyns=%20&t=09_Parameters%2FDFE%2Fdfe.htm) or Dual-Node-Connectors (http://www.feflow.info/html/help71/feflow/mainpage.htm#rhhlterm=arbitrary%20node%20path&rhsyns=%20&t=09_Parameters%2FDFE%2Fnodesplit.htm).