Design Challenges of Full Field Waterflooding Project in a Southern Iraq Oil Oilfield

Field A is a giant oilfield located in southern Iraq where reservoir Y is the main reservoir target. An inverted 9-spot patternflooding technique with 600m spacing will be employed during the waterflooding phase. As with any waterflooding project in carbonates, huge uncertainties and risks are associated with the planned waterflood project.

The biggest uncertainty is associated with the injectivity in the reservoir where failure to achieve target injection target can either result in inability to maintain reservoir pressure, hence not meeting the contractual production target.

The associated risk of poor vertical sweep efficiency is apparent from PLT survey. Risk on water channeling resulting in early water breakthrough in top part of the reservoir is serious.

Water from nearby river has been identified as the primary water injection source though the availability throughout contract period is still a concern.

Another challenge associated with the project is the need to dispose the offspec injection water as with any other onshore waterflooding projects.

Mitigation measures for the above uncertainties are in place and will be discussed in this paper. Design flexibility has been incorporated as part of the mitigation measures to minimize the risks associated with these uncertainties.