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Case Study: Identify Oil Entry in Complex Horizontal Well with 98% Water Cut, North Sea

Flow Scanner system’s production logging of complex flow regime locates oil entry below the resolution of conventional logging

Challenge: Identify minor oil entry points to guide intervention in a North Sea horizontal well with water cut to 98%.

Solution: Run Flow Scanner horizontal and deviated well production logging system with its integrated multiple minispinners and probe arrays to obtain unambiguous multiphase velocity and holdup profiles.

Result: Remedial action targeted two zones where Flow Scanner system logging revealed oil holdup, increasing the net oil rate by 30%.

Finding oil entry in extremely high water cut

Logging was needed to guide intervention in a marginal North Sea horizontal well penetrating a Jurassic age reservoir. Because water cut was as high as 98%, conventional production logging tools did not have sufficient resolution to identify the minor oil entry points.

Profiling multiphase flow in a horizontal well

Unlike conventional production logging tools, with their single, central spinner for use in vertical wells, the Flow Scanner production logging system integrates minispinners and optical and electrical probe arrays that make multiple measurements simultaneously in the same vertical cross section of the well. Characterizing the individual components of multiphase flow through the resulting fluid holdup and flow profiles enables separating the effects of the well trajectory from real fluid entries into the borehole.

Targeting zones with oil holdup for remedial action

As shown on the first two tracks of the log, water holdup is high, as predicted for the well trajectory and water cut. Zones 1 through 4 are the source of major water entry. Only the fifth minispinner (tan curve) at the top of the measurement cross section is responding to a faster-moving, thin oil layer originating from Zones 5 and 6. Conventional production logging would not have detected the small amount of oil measured by the Flow Scanner system from those two zones.

On the basis of the oil entry information, the operator reperforated Zones 5 and 6, which increased the net oil rate by 30%.


Download: Identify Oil Entry in Complex Horizontal Well with 98% Water Cut (0.79 MB PDF)

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Oil Holdup Revealed to Increase Net Rate 30%

The Flow Scanner downhole flow and holdup profiles and cross sections identified previously undetectable oil entry at Zones 5 and 6.
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