High Potential Near Miss Dropped
Object
Dropped Wrench While Man-riding
17th Sept 2010
Incident Investigation Findings
Rowan JP Bussell
Presented by :
Steve McWilliam, Shell Egypt N.V.
OVERVIEW OF INCIDENT
17th September 2010 at 17:15 hrs. After completion of a liner cement job, a floorman was instructed to ride the
man-riding winch to close the lo-torq valve and remove the cementing line. Employee ascended with hammer
and TIW wrench and prior to closing the valve, the wrench weighing 1.8 kg fell 14 metres to the drill floor.
No injuries occurred.
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POTENTIAL SEVERITY - Fatality
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WHAT HAPPENED
Liner was pulled back 2.5 metres after tagging bottom and cement job performed. The operation of closing
valve was done after pulling back the liner running tool to the circulating position – hence working height of 14
metres.
Work Permit, Job Safety Analysis and man-riding checklist were in place for the job (more details in later
section)
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WHY DID IT HAPPEN (Immediate Causes)
Snap hook connector not used correctly – tether should pass through the eye of the connector to prevent
accidental drop-out.
 Tools
aloft hammer was correctly tethered but not the wrench.
Snap hook connector did not have locking device.
 The
above two conditions would allow the tether to drop out if the connector rotates – confirmed by
reenactment.
Although disputed by floorman, the tool could have been removed from the connector to perform the task.
Correct
Incorrect
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CONTRIBUTING FACTORS (Failed / Missing Barriers) (1)
The running string was not spaced out or positioned to minimise the height at which this activity was
performed.
The rig procedure for Working At Heights, identifies the risk of dropped objects and specifies the use of tool
tethers and tools aloft register.
 However,
the requirement of only one tool per tether and the requirement to only use approved tethers
through the eye of the connector is not explicitly stated in the procedure.
A pre-man-riding checklist was completed by the AD on the man-riding floorman prior to the job. However,
this check was not effective in identifying the use of non-compliant tether.
 The
checklist was only available in English so Egyptian buddy-buddy checks not possible
 The
requirement to use checklist and the responsible person is not identified in the Working at Height
procedure
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CONTRIBUTING FACTORS (Failed / Missing Barriers) (2)
Although snap hook connectors have been ordered as part of tool aloft kit from a reputable North Sea
provider, the supplied connectors without locks are not aligned with the DROPS Forum handbook “Reliable
Securing”.
Zip tie is not an approved tether and it’s short length (~30cm) may result in requirement to remove tool
from connector to more easily perform the task. Zip tie was connected for purpose of hanging it on a hook
outside the driller’s cabin.
There is no dedicated “tools aloft” tool for this job. Although the TIW (kelly cock) wrench is not the
correct tool for the job, it was the best available at the time. The dedicated lo-torq wrench is a straight rod
that is more difficult to use especially when working at heights.
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ROOT CAUSES (1)
DROPS Forum requirements for locking connectors has not
fully penetrated the tool suppliers.
 Examples
of tool tethers from UK suppliers
Non-compliant with DROPS Reliable
Securing
Compliant with DROPS Reliable
Securing Handbook
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ROOT CAUSES (2)
Ergonomic “tools aloft” tool for closing lo-torq valves at height does not appear to exist.
Due to the frequency of man-riding activities on the JPB, there is a possible perception that it is routine
activity, even though it is covered by PTW.
 As
a result, thoroughness / quality of pre-manriding checks inadequate
Insufficient challenge by the team to minimise the number and height of man-riding operations.
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OTHER OBSERVATIONS
All personnel involved (AD and 3 floormen) had attended the Tools at Height training and competency
assessment forms completed.
“Red Zone” procedures were in place for controlled drill floor access and the area had been cordoned off for
this job.
Requirement for man-riding during cementing operations :
 Cementing

operations requires 5 man-riding activities to connect / disconnect lines and open / close valves.
Floating drilling operations predominantly use pneumatic plug dropping heads due to the ban on man-riding activity while
block is moving (drill string is compensated while cementing)
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ACTIONS
Corrective Action
1.
Take snap hooks (without locking) out of service and temporarily replace with 4-part shackles with split retention pin.
2.
Procure snap hooks with locking mechanism for use with tools aloft kit.
3.
Review the availability and suitability of pneumatic plug-dropping head for future casing and liner cementations
and liner cementations
4.
Conduct systematic review of all man-riding operations with aim to eliminate or reduce height of activity. This to include list of tools
height of activity. This to include list of tools required for the job
5.
Design / Procure a dedicated tool for closing lo-torq valve at heights
6.
Translate the man-riding check-list into Arabic
7.
8.
Revise the Rowan man-riding procedure to specify more details on type and use of tethers and snap hooks or shackles with secondary
tethers and snap hooks or shackles with secondary retention. Specify responsibilities and use of man-riding checklist i.e. buddy checks
and use of man-riding checklist i.e. buddy checks and final check by supervisor before man-riding.
man-riding.
Feedback incident learnings to supplier of tool aloft kit and DROPs Forum.
9.
Review compliance against the DROPs Reliable Securing and close out gaps.
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SENV WELLS Learning From Incidents
Fountain: 564176
Location: Egypt – NW Demiatta
NM: Dropped Wrench While Man-riding
Date: 17th Sept 2010
Background : This bulletin is an extension of the previous Early Learning Bulletin, subsequent to the full
investigation and significant incident review. It also includes the recommendations considered most appropriate for
lateral learning value.
What happened: After cementing the liner, a floorman was instructed to man-ride to close the lo-torque valve and
remove the cementing line from the cement head. The floorman ascended with hammer and wrench but before the
valve could be closed, the wrench weighing 1.8kg fell 14 metres to the drill floor. No injuries occurred.
Investigation Findings:
 Zip tie is not an approved lanyard. Its short length
(~30cm) may have required the tool to be removed
from the connector to perform the task.
 The snap hook connectors were supplied as part
of a kit from a reputable North Sea provider, but
were not compliant with the Shell DROPS ABC
Best Practice or the DROPS Forum Reliable
Securing handbook which requires connectors to
have a locking device.
 Snap hook connector was not used correctly;
cable tether should pass through the eye of the
connector to prevent accidental opening of the
gate.
 There is no dedicated “tools aloft” tool for this job.
 “Tools At Height” video shows use of non locking
connector.
 Red Zone Procedures (controlled drill floor
access) as well as physical barriers for this
particular job were in place and provided
mitigation against serious injury.
 DROPS gap analysis is only conducted against
the mandatory requirements and a good level of
compliance had been achieved. However, there
Compliant connector
are a lot of further best practices in the DROPs
with locking
ABC that may not be captured in the gap analysis.
Non-compliant (non-locking)
connector and tether
Lateral Learning Recommendations:
 Check the type of snap hook
connectors in the tools aloft kit to
ensure they have a locking device
 Review the tools aloft kit to ensure
that it contains tools to perform all
foreseeable working at heights
tasks.
 When rolling out the Tools At Height
training, indicate the use of noncompliant connector when Peter
clips the tool on the tether.
 Once a good level of compliance has
been achieved against the DROPS
mandatory requirements based on
gap analysis, it is recommended to
systematically review compliance
against the DROPS ABC Guide.
Q&A
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