Page 404 - Practical Well Planning and Drilling Manual

Section 3 revised 11/00/bc 1/17/01 12:00 PM Page 380

[ ] Practical Wellsite Operations
3.3.10

8. If the plug has worked, bullhead cement below it. If the pumping
or casing pressure fluctuates significantly, this may indicate that
the DOB plug has not held. Under-displace the cement to plug the
drillstring to the theoretical top of the plug.
9. Wait on cement; pressure test inside the drillstring. Bleed off and
check for backflow.
10. Perforate the drillstring, using the pressure lubricator in case flow
starts. Attempt to circulate.
11. If possible to circulate, displace out any formation fluids with a
mud density that will stop the losses. Then when the well is static,
backoff or blow off the drillstring at or above the perforation depth.

If not possible to circulate, set a wireline plug above the perfs, pres-
sure test, and reperforate higher using steps 10 and 11. Ongoing oper-
ations would probably be to P&A the well or to set casing to below the
loss zone prior to sidetracking.

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