High downhole pressure prompted buildup test and further analysis
The well production evaluation registered an abnormally high downhole
pressure. The well was producing 2,050 bbl/d with 100% basic sediment and
water, and the ACTive PTC tool's downhole sensors were reading a 2,984-psi
[20.6-MPa] downhole flowing pressure. This pressure did not match the estimated
reservoir pressure of the zone of interest, which was 1,900 psi [13.1 MPa].
After eight hours of flowing the well, the operator decided to perform a
pressure buildup test to further analyze the well. The pressure buildup was
registered with the ACTive PTC tool downhole sensors, showing a reservoir
pressure of 4,000 psi [27.6 MPa], confirming that the well production was from
another formation. Using the fiber optics inside the CT string, distributed
temperature sensing (DTS) profiling was performed and identified crossflow
between two zones behind the well casing. A remedial cement job was scheduled
to resolve the problem.
Crossflow behind casing identified in a matter of hours instead of
With the conventional method, the operator would have had to evaluate
the well for several days while the reservoir pressure dropped and water cut
stabilized and would not have been able to confirm the source of the water.
Using real-time data at surface, the operator identified the crossflow behind
the casing and completed the buildup test and well production evaluation in
only 17 hours, saving several days of rig time.