Abstract
High permeability reservoirs in Deepwater Gulf of Mexico have been completed with fracpacks resulting in high production rate wells. The initial production rates for these wells range from 3 mbd to almost 40 mbd; and these rates can be sustained over extended periods of time (several years). Most of these developments in the Gulf of Mexico require sand control with cased hole fracpacks as the preferred completion technique. In addition to providing reliable sand control, fracpacks result in relatively low skin by bypassing near wellbore damage. Over the past few years, operators have focused on reducing skin and improving the production from these wells; leading to a more detailed analysis of fracpack performance. This paper will demonstrate that in high permeability reservoirs, production from the off-plane perforations is as important as production from the fracture. It examines the theoretical basis of the contribution of off-plane perforations to total flow and demonstrates the adverse effect on this contribution due to damage from drilling fluids and solids, cementing spacers and solids, fluid loss materials, perforating debris, wellbore debris, and crosslinked gel. Several case histories are analyzed to evaluate and quantify these effects and to show that the lower the conductivity contrast between the (high permeability) reservoir and the fracture, the higher the production benefit that can be realized by effectively cleaning the off-plane perforations.
