Water coning reduces oil recovery and increases surface costs
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.
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.