In deepwater projects it is often necessary to complete long intervals in highly variable, heterogeneous reservoirs. For frac and pack completions it is important to understand the fracture geometry and growth characteristics sufficiently well to ensure that the complete interval can be effectively treated as to provide long-term productivity and sand control. This presentation reviews two completions where good quality openhole log data were available, along with downhole pressure/temperature gauges and radioactive tracer images of downhole proppant placement. A finite element hydraulic fracture simulator was employed to establish a fracture history match that would honor all of the available data, including the temperature gauge data and tracer image. The results of this study reveal some very interesting aspects of hydraulic fracture growth in heterogeneous reservoirs, including complex fracture growth and instances of slurry diversion occurring during the treatment as one or more fractures begin to screen out. It will be demonstrated that the fracture simulator can be a very effective means to tie all of the available data together in arriving at a single solution. It will also be shown how the procedures employed can be used by completion engineers in making decisions as to when long intervals can best be treated in a single stage vs. when it would be more advisable to break such an interval up into multiple treatment stages. The use of more rigorous fracturing models will be shown to be a practical and effective means for understanding and improving frac and pack completion designs for long intervals.