Ekofisk Field (in the Norweigian sector of the North sea) is a remarkable example of a strongly compacted chalk reservoir. Since the start of production in 1971, the water bottom has subsided by over 8 m as a result of reservoir compaction (Hermansen et al.). The field-wide waterflood, begun in 1989, was expected to halt pressure depletion and reservoir compaction. After a few years of waterflooding, Ekofisk reservoir pressure began increasing, but compaction and subsidence continued. Laboratory studies on chalk cores indicated that high-porosity, oil-filled chalk compacts strongly when flushed with seawater. These studies, along with reservoir flow simulation and...

First Page Preview

First page PDF preview
You do not currently have access to this article.