Effective waterflood and pressure maintenance are critical to the economic viability of the many developments in which oil production and reserves recovery are underpinned by water injection. In BP some 60% of current oil production is supported by waterflood and this is expected to rise to 80% over the next few years. Many of the future developments will be in sand prone formations where sand control will be required in the injectors. Further, an increasing number of these developments will be located offshore in deepwater, making use of subsea wells and wet trees. In this challenging economic and operating environment the completion design philosophy will increasingly focus on higher reliability and minimal well intervention.
However, the sandface completion design for water injectors is now recognized as a major technical issue with the key areas for concern being:
• Life of well sand control integrity, particularly where the sands may be subject to water hammer, zone-zone crossflow or well-well backflow
• Long term injection performance, particularly with solids laden produced water and with injection pressures above or below fracture pressure
• Reliable and cost effective zonal isolation, to provide zonal selectivity and improved injection conformance
So how do the various completion design options meet these concerns and what performance can be expected in the field?