Intervals with marginal production potential often are bypassed during early stages of reservoir development. As reservoirs mature, production from these bypassed intervals can offer an economical alternative for production enhancement when compared with infill-drilling or redrilling operations. Effective fracture stimulation of such pay zones with conventional techniques can be limited by operational considerations. Integration of coiled-tubing (CT) operations into hydraulic-fracturing procedures and use of a polymer-free fluid overcome many constraints associated with the stimulation of bypassed pay zones.