Page 342 - Practical Well Planning and Drilling Manual

Section 3 revised 11/00/bc 1/17/01 12:00 PM Page 318

[ ] Practical Wellsite Operations
3.1.2

For a pit drill, the toolpusher or drilling supervisor will do some-
thing to cause the pit volume totalizer system to show an increase in pit
volume. When float type detectors are used, these can be pulled up.
Mud can be pumped into the active system from a reserve tank or the
trip tank. The driller should respond by stopping the rotary and pumps,
picking up off bottom, and doing a flowcheck. The driller will not nor-
mally close in the well on a pit drill; the flowcheck will show that all is
well and the drill can be stopped once the flowcheck is initiated.
A trip drill is normally initiated by the driller to train the crew. It
is good practice to stop for 10 minutes in the shoe when tripping out,
which can be combined with a trip drill every time. The objective here
is not speed but correct action; it is much more important to do it in
the correct sequence than it is getting it fast. Speed is the ultimate
objective, but if they practice the sequence on every trip, when it is
done for real it should be both accurate and fast.
This is one suggested way of holding a regular trip drill. The driller
pulls into the shoe, breaks off the stand. The block is stopped halfway
down and the driller shouts “trip drill.” The crew picks up the full
opening kelly cock and stabs it into the drillpipe. The kelly cock is
made up hand tight and closed.
(At this point in a real kick, if strong backflow is coming up the
drillpipe, the crew has to get that kelly cock on and closed. They may have
to do this by feel in an extreme case. Once the kelly cock is closed then the
flow will stop—apart from maybe some minor flow from the hand-tight
connection, which will stop once the tongs are on and the connection
tightened. For the drill, it is not necessary to torque up the connection.)
The driller now lowers the block and latches the elevator, picks up
the string and the slips pulled. The casing shoe flowcheck can now be
done with the kelly cock in place. If a flow is detected then the driller
only has to close in at the BOP as the kelly cock is already on. After
confirming that the well is static, the string can be set in the slips, the
kelly cock removed, and the trip out resumed.
Precautionary flowchecks should also be done when tripping back
into a horizontal wellbore. A swabbed influx can stay in the horizontal
section to be displaced out when tripping back in. Since the hole may
have been static for several hours, the drill crew may not expect a prob-
lem. Now that the influx is out of the horizontal section it moves up
and, if gas, can cause the well to start flowing as the gas expands and
hydrostatic reduces.

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