H E A LT H , S A F E T Y, E N V I R O N M E N T & T R A I N I N G
Mitigating drops risks through
pipe screen replacements, red
zone management technology
BY STEPHEN WHITFIELD, ASSOCIATE EDITOR
Dropped objects have continued to pose a
significant safety hazard on drilling rigs
over the years. At a DROPS (Dropped
Objects Prevention Scheme) meeting on
2 November, industry stakeholders came
together to look at two sides of the effort
to mitigate potential dropped object risks:
removing the dropped object from the rig,
and keeping people on the rig away from
the dropped object.
The meeting featured discussion on the
development of a digital system designed
to set up “exclusion zones,” or areas of
the rig where personnel are not allowed
to enter at a given time. It also looked at
as the efforts a drilling contractor took
in eliminating the risk from a specific
dropped object on its rigs.
On the drilling contractor side,
Ryan D’Aunoy, Senior Manager of HSE
Management Systems at Precision
Drilling, spoke about various lessons the
company learned from its near-misses
with one particular dropped object, over-
head drill pipe screens.
Pipe screens are designed to prevent
solids from being pumped downhole while
drilling, improving the viscosity of the
drilling fluid by filtering out solids. They
also prevent blockage of the ports in down-
hole tools.
Precision utilized two types of over-
head pipe screens: Downhole filter screens,
which can be placed anywhere in the drill
string but are typically installed directly
above critical equipment, such as the bot-
tomhole assembly, as well as surface drill
pipe screens, which are positioned in the
top stand of the drill pipe and never go
below the rig floor.
Mr D’Aunoy pointed out that both pipe
screen types require removal and cleaning
after each stand, and crew members have
to handle them while they’re positioned
above the rig floor because there is no way
40 to securely move them into the derrick.
This need for manual handling of over-
head equipment can introduce potential
risk for injury or even fatality.
Precision saw four dropped pipe screens
in its operations in 2022. Two incidents
occurred because the saver sub threads
stripped, causing the stand to fall into
the pipe elevators. Two other incidents
occurred because the drill pipe was rotated
out at the top drive and, as the stand
was moved to be stabbed into the mouse-
hole, the grabber boxes could not hold the
weight of the drill pipe. The stand broke
free and dropped from the grabber box into
the drill pipe elevators.
In all four cases, the pipe screens were
ejected from the pipe and fell approxi-
mately 90 ft to the rig floor. There were
no serious injuries or fatalities in either
incident. However, the Dropped Objects
consequence calculator showed that, if a
crew member had been struck by the pipe
screen, the incident could have resulted in
a fatality.
“If a pipe screen was to strike some-
body on the rig, you’re definitely looking
at a serious injury or fatality potential
given the weight of the pipe screen and
the heights that they’re falling from,” Mr
D’Aunoy said. “As we investigated these
incidents, we needed to look at our hier-
archy of controls to see what we could
do about these screens, maybe see if we
could just completely take them out of the
equation.” In its investigation of the incidents,
Precision discovered that some of its oper-
ator clients had begun running inline pipe
screens, which are installed in the drilling
fluid piping system on the rig floor, instead
of above the rig floor. Instead of cleaning
these screens after each stand, crew mem-
bers clean them prior to running casing,
and since they aren’t installed above the
rig floor, the dropped object risk is elimi-
nated. Precision then decided it would
stop using overhead pipe screens.
Precision began replacing its overhead
drill pipe screens with inline screens in
June, with replacements completed for
the majority of its rigs by November. While
inline screens could be a viable alternative
for drilling contractors industrywide, Mr
D’Aunoy acknowledged that cost may be
a prohibitive barrier for some companies.
“You haven’t seen much about these
pipe screens being dropped, except around
where employees were handling them
overhead or placing them into the pipe,
because there are no means to secure
them,” he said. “Each company has to
look at the risk/benefit analysis prior to
using these pipe screens overhead. With
us at Precision, we’ve gotten to the point
where we’re just not going to do it anymore
because of the risk.”
Keeping people out of harm’s
way in red zones
During the DROPS meeting, FSC Systems
presented its zone management technolo-
gy, which combines radio-frequency iden-
tification (RFID) with infrared technol-
ogy to provide instantaneous feedback to
drillers on personnel movements around
hazardous equipment through electronic
barriers. The system monitors the presence of
human activity in pre-determined exclu-
sion zones. Infrared sensors are installed
throughout the rig and can be combined to
create boundaries for the exclusion zones,
each of which contains its own unique ID.
It does not utilize wearable technology –
instead, the sensors are wired directly to
a control panel, and when personnel enter
an exclusion zone, it provides instanta-
neous feedback through an audible alarm.
The driller can then stop work in the
exclusion zone before a potential incident
may occur.
The lack of a wearable sensor element
means that the zone management system
cannot determine exactly who entered
a zone, but Brennan Flores, Petroleum
Engineer at FSC, said that this system can
provide a more cost-efficient alternative
compared with wearable systems, making
it easier to justify economically. Further,
“with the direct connections to the panel,
JAN UARY/FEB RUARY 2023 • D R I LLI N G CO N T R ACTO R