Page 243 - Shale Shakers Drilling Fluid Systems

DERRICKMAN'S PACES 225

Shaker screen replacements should be made 6. Except for cases of lost circulation, the shale
as quickly as possible. Locate and arrange shaker should not be bypassed—even for a
tools and screens before starting. short time.
• If possible, get help. This will decrease 7. The possum belly should not be dumped into
the amount of cuttings being kept in the the sand trap just before making a trip.
mud because the shale shaker is not run- When the next bit starts drilling, the cut-
ning. If possible, change the screens dur- tings will move down the mud system and
ing a connection. plug the desilters.
• In critical situations, the driller may want
to stop the pumps and stop drilling while Each of these seven rules is very important to
the screen is replaced. maximize cuttings removal.
Water should not be added in the possum
belly or on the shaker screen. Water should
be added downstream.

Things to Check When Going On Tour

1. Make sure the shale shaker is running properly.
2. Check for mud flowing properly over the shaker screen.
3. Check for holes in the screen.
• Wash off the screen during a connection for this examination.
• Sometimes a flashlight is needed to examine the whole surface.
• Most frequently holes appear where the overflow from the possum belly strikes the screen.
• If a riser-lift pump is used to help move mud up the riser, divert the flow to one shaker during a connection so
that all screens may be examined.
4. Replace the screen, if necessary.
• On panel screens, the holes may be plugged or blanked.
• Minimize downtime by planning your work.
5. Make certain water is not being added at the shaker.
6. Check for cuttings, not mud, going off the end of the screens.
7. Check cuttings reaching the shaker to make certain that they have sharp edges.
8. Report findings to the driller and/or rig supervisor.
The above rules will help drill a well at the lowest possible costs. Shaker performance is an important part of a trouble-
free, lowest-cost well.