Water coning reduces oil recovery and increases surface costs

For naturally flowing oil wells with strong aquifer support, one of the most significant challenges for extending productive life is high water production caused by coning. Producing the water too soon reduces net oil production from the naturally flowing well in the long term and increases surface water handling requirements in the short term. Increasing surface water handling capacity incurs additional costs; therefore, production must be limited to sustain production within the limited capacity of surface water facilities.

For Kuwait Oil Company (KOC), the conventional solution to early water production is to partially perforate across the oil column above the OWC and install tubing sized to maximize the natural flow life cycle. However, water cut still tends to increase.

In Well A, only 55% of the oil column was perforated, but production still reached 53% water cut within 6 months and 74% water cut after 4 years. To extend the natural flow of the well, KOC investigated an alternative technical solution.

New technology draws water away from the oil zone

DWS technology improves oil production in vertical or moderately deviated wellbores (<60°) by creating a pressure differential to draw water away from the perforated interval. The fundamental principle of the technology is to create an equivalent pressure drawdown or pressure sink ΔP at or just below the OWC, within the water layer, that is equal to or marginally less than the ΔP across the perforated interval within the oil layer. This drawdown reduces the progression of the water cone into the oil column and is achieved with a high-volume ESP.

The pressure sink creates a preferential flow of bottom water or edge water, parallel to the bedding plane, just under the OWC. The water can then be injected directly into an underlying aquifer or produced to surface for processing and reinjection in a disposal well.