Page 402 - Practical Well Planning and Drilling Manual

Section 3 revised 11/00/bc 1/17/01 12:00 PM Page 378

[ ] Practical Wellsite Operations
3.3.9

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 7 and 8.
Ongoing operations would probably be to P&A the well or to set
casing to below the loss zone prior to sidetracking. If the barite plug
fails, also consider using a diesel oil bentonite plug. If the kick is water,
a DOB plug will have a higher chance of success.
High pressure, low permeability kicking formation. In this situa-
tion, the intention is to isolate the kicking formation without weight-
ing up the entire mud system for a normal kill and leaving the drill-
string clear and free after the operation. Situations making this neces-
sary may include, for instance, problems with barite supply or rig
equipment preventing a normal kill operation.
Preparation. You need to pull above the plug quickly after displac-
ing. A hose or chiksans on the standpipe can be rigged up so that the
first stand can be pulled and racked immediately after pumping ceases.

1. Mix, pump, and displace the slurry right out of the drillstring; keep
working the pipe slowly (stripping through the annular if neces-
sary). If a float is in the string, overdisplace by 5 barrels, otherwise
leave about 3 barrels inside the string to prevent backflow.
2. Backoff the hose and circulating head from the drillpipe as soon as
pumping is stopped. Pick up in stands to about a stand above the
planned top of plug, stripping if necessary. Make up the hose again.
3. Start to circulate slowly over the chokes; continue to work the pipe
slowly through the annular. If the plug works, influx/gas levels in
the returns should decrease to near zero. If this does not happen
after 2-3 circulations, set another plug.
4. When the well is dead, run back in to the theoretical top of the
plug. Set a balanced cement plug on top of the barite plug.

Ongoing operations would probably be to P&A the well or to set
casing to the top of the cement plug prior to drilling ahead. If the barite
plug fails, also consider using a diesel oil bentonite plug. If the kick is
water, a DOB plug has a greater chance of success.

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