OPENHOLE HORIZONTAL COMPLETIONS IN NIGER DELTA

The Niger Delta is a highly activity region in open hole applications. A wide variety of completion types have been deployed in open hole in the region. A major challenge in these completions is to deliver quality wells through the choice of an optimal sand control system. A locally developed database tracks the performance of the sand face completions, their reliability, observed failures and their causes. The oil reservoirs have used barefoot, standalone screens, slotted liners, gravel packs and expandables while pre drilled liners have been use for borehole support. The expandable technology is relatively the most recent technique but of the three hundred and forty run so far globally, more than 3/4 has been deployed in Niger Delta alone.

For the non associated gas reservoirs, based on fair understanding of the risks and uncertainties associated with two main sand control options namely, gravel packing and the expandable sand screens, work was done to show adequate demonstration of the process of selection. This structured approach considers design options based on several factors such as possible problem with under reaming relatively deep section, previous performance in the existing high rate gas wells, productivity and better life cycle design perspectives.

Within the Darcy permeability regime of the sandstone gas reservoirs, productivity with respect to horizontal wells, conventional wells was compared and a matrix capturing the risks impact of a horizontal gas well is also discussed.

The work concludes by suggesting future concerns in open hole sand control to include cost of installation failure, accurate modelling upfront and remedial zone isolation after gas/water breakthough