Fracture driven interactions (FDI’s) within a drilling spacing unit (DSU) have been a topic of concern in organic shales. Failure to protect primary wells from infill well FDI’s can result in up to 40% EUR losses from asymmetric fractures. Adverse FDI’s between wells can be eliminated with a combination of primary well refracs and infill well zipper fracs, and refracs are significantly more cost effective than preloads, which protect only the primary well. While results from mechanical isolation have been more consistent than diverters, the issue now is what mechanical system is the most effective. In spite of their higher initial cost, expandables are significantly more cost effective than cemented liners, when the full completion cost is considered.