Drop kelly hose clamp

Drillsafe - Brisbane - 2nd June 2011

Dropped Object – Kelly Hose Clamp 15th March 2011


Sequence of Events

Time Event

18.30 hrs • Driller encountered tight hole at 1,114 metres prior to making a connection. Night DSV on the rig floor when tight hole encountered.

• All non essential personnel were cleared off the rig floor. • Continued to work the string to free for 1 ½ hours

19.30 hrs • Day DSV arrived on site. • Driller still working string to get free.

20.00 hrs Approx

• Night Toolpusher took over controls from Driller. • Day DSV instructed Night Toolpusher to trap 30kft/lbs torque in the

string and try to work the string free. 21.00 hrs • TDS was about 8 metres off the floor. Jar fired while picking up.

240,000 lbs on weight indicator. • Kelly Hose Clamp fell to the rig floor. INCIDENT. Clamps weighed

8kg. 21.15 hrs to 21.30

• Driller inspected TDS, Kelly Hose, Safety Clamps in Derrick. • New Kelly Hose Clamp fitted. Failed clamp taken to HSE Office


What actually happened

• Under normal circumstances the Kelly Hose often makes contact with the Deflection Rail during travel.

• Correct orientation of the Gooseneck and Kelly Hose Clamp is very important.

• During rough drilling the TDS Torque Track Lower Tie Back which is designed to hold torque tube over hole centre constantly needs to be retightened and repositioned.

• When torque was trapped in the drill string, reactive torque was present which was forcing the Torque Track an TDS to the left or standpipe direction.

• It is very likely when the jar fired up, the bent the deflection rail and allowed the Kelly Hose safety clamp to hit the hammer union wing. This is supported by red paint found on the deflection rail.



What actually happened cont;

• The securing bolts on the safety clamp are well protected and how they actually sheared could not be confirmed.

• It is believed that the safety sling retainer lug on the Kelly Hose Clamp was orientated directly towards the standpipe and the lug on the clamp struck the hammer union wing.

• The safety clamp that fell was secured with a secondary fall safety wire rope sling.

• The safety clamp purpose is to prevent the Kelly Hose from falling. The safety clamp design would not prevent the Kelly Hose Safety Clamp itself from falling.

• The bolts used to secure of close the clamp around the Kelly Hose are also used to retain the safety sling retainer lug.

• The outcome was that when the safety clamp fell, the safety sling remained in position.


Clamp has been rubbing against Deflector Rail

Bolts to close clamp and secure safety clamp lug attached to safety sling.

Point of contact for the Kelly Hose Safety Bolts


Safety Clamp Assembly


Injury Outcome


Incident Causes

Immediate Cause • Safety Clamp bolts sheared and clamp fell to the rig floor

Underlying cause • Design of Kelly Hose Clamp safety line attachment point.

Safety line attachment point should retain safety clamp when bolts sheared.


Remedial Actions

Action Status

Amend rig up procedures to ensure retainer lug on the Kelly Hose Clamp is orientated towards the TDS and Crown Nuts are used with lock wire.

Completed.

Modify or replace the existing Kelly Hose Clamp so that the secondary fall device retains the clamp at height if any of the bolts are sheared or inadvertently dislodged.

Waiting on parts


In closing

• High Arctic has a comprehensive Drops Object survey for all rigs.

• In this particular case the survey identified that the Kelly Hose had a secondary fall safety device i.e. safety sling.

• It identified that the secondary was properly secured i.e. 4 point shackles.

• It did not identify that the secondary fall device would not prevent the Kelly Hose Clamp from falling.


Thank you

Any questions

Documents

Drop kelly hose clamp