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For many, especially non drilling people the rig
pumps are just a means of circulating the well while drilling, in
this day and age having a pump down should not shut down
the rig, all new builds now install a minimum of 3 pump that have a
rated working pressure of 7500 psi.
Most rig pumps install nowadays are single acting
positive displacement pumps that are force feed by a charging
(centrifugal) volume pump.
Running a pump program will effectively eliminate
downtime while drilling or circulating under normal conditions
Keeping the drilling fluid properties under
control (such as the solid content ) is another major issue that if
left to get out of control will cause havoc not only with the pumps
but all the high pressure lines and equipment associated with the
circulating system.
The rig pumps are normally monitored by the
derrick man or a pump man, understanding the pumps is possible the
most important position a person will have before taking on the
position of driller. Issues and problems that are associated with
the pump pressure can and often do have a devastating effect when
not understood,
A Pressure drop with a stroke gain will always
indicate a change of parameter within the circulating system, there
are a number of issues that will cause this, a change in drilling
fluid properties, a pump problem on surface these can be fixed
without too much of a problem, however there are some problem that
if not recognise and dealt with as soon as possible
will cause downtime.
One such issue is a washout in the drill string,
all too often and due to lack of experience drill strings a left
down hole having dropped off after the pipe washed out, under normal
condition the string can be fished out, this is
time consuming, non productive and costly,
under more adverse condition it could possibly cost the section of
the well that was drilled and a re-drill,
Had the drillers
serve their time as a derrick man,
they would have reconised the sign
(signals from the pump)
and
would have reacted in a much more positive manner, checking his
pumps, mud weight and other parameters, valve in the system,
and
if not satisfied would have been removing the pipe wet from the
wellbore.
A derrick man that tells the
driller there is a pump problem developing before the driller tell
him is an asset to the rig, on the other hand when the driller has
to phone down and ask the derrick man to check out his pumps due to
a pressure loss in the circulating system is a liability to the
operation and should be monitored carefully until such time as they
are trained and can be trusted or replaced.
At the time of
rewriting this page, February 2008 we are in the middle of a major
rig building program,
some 30 rigs will go online during the coming year, more will follow
next year, day-rates are at all time highs, experienced people are
at an all time low, we will be looking for over 20,000 people to man
the rigs,
As stated the pumps now have a rated working
pressure of 7500 psi and a rated drilling capacity of 35000/40,000
feet, therefore we can expect some high pressure low volume
circulating pressure, therefore pump maintenance and understanding
is crucial to the operation if we are to push the boundary of
drilling to new upper limits,
At
the rates they are paying for to-days rigs, one should not and
cannot expect the operator to sit back and except 2 or 3 hours
downtime for pump repairs or fishing trips to recover lost strings
of pipe it is our responsibility to see that our people have
the time to train and are trained properly and understand what is
expected of them. experience will only be gained with time, but
knowledge can and should be handed on
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