Page 175 - Practical Well Planning and Drilling Manual

Section 2 revised 11/00/bc 1/17/01 12:04 PM Page 151

2.2.2
Well Control [ ]

is aware of actions to be taken in various situations.
Be prepared to evacuate nonessential personnel if a kick is taken
and for complete evacuation if necessary.
Hold regular drills before and during drilling top hole. This should
include function testing of the diverter system.
Be prepared to plug and abandon the well if shallow gas is identi-
fied, even if it does not kick straight away.
Ensure that written procedures are in place and accessible to the rig
crews. These should define actions to be taken, move-off procedure
(floater), etc.
If the well kicks, men should be already assigned to shut down
nonessential equipment, ventilators, etc.

2.2.2. Drilling with a BOP Stack

When the casing has a competent shoe, the blowout preventers can
be nippled up. The setup will depend on company policies, type of rig,
available equipment, etc. It should be possible to connect the choke
and kill lines above the bottom rams and have spare, valved outlets for
the choke and kill below the bottom pipe rams. If the choke and kill
lines are below the bottom rams and a leak occurs at the ram side out-
let, the flow could not be controlled.
The blind rams should not be the bottom set. This allows the pipe
to land on the bottom pipe rams, be backed off (or sheared) higher up,
and circulation to be established. On a surface stack the blinds should
also not be the top set of rams, so that in the event of leaking upper
pipe rams, the blinds could be closed allowing the top pipe rams to be
changed out. On some BOPs (e.g., Shaffer), normal pipe rams are not
designed to support the weight of the drillstring. Check with the BOP
operating manual. Shaffer rams for supporting pipe weight have a spe-
cial metal insert on the top edge where the tool joint will land.
Variable bore pipe rams (VBR) can close on a range of pipe sizes.
VBRs should not be run as the bottom set; a drillstring cannot be land-
ed on closed VBRs. Using VBRs can avoid having to spring the bonnets
open and change rams for certain mixed drillstring configurations.
When drilling with BOPs, the casing shoe should be tested after
drilling out to determine the formation fracture pressure and the max-
imum allowable annular surface pressure (MAASP). This establishes
the point at which the formation will just start to take fluid and must

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