Slickline Hand Jarring results Lost Time Injury

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Alert ID: 
Description of Process: 

Hand jarring during slickline operations

Description of Incident: 

Whilst carrying out well services operations on an NUI (Normally Unmanned Installation), a member of the well services crew sustained an injury to their lower right leg.

At the time of incident the injured person (IP) was in the process of hand jarring the wireline and in doing so he placed his right foot on top of the horizontal section of the wire to apply downward pressure. At the same time, he pulled the vertical section of the wire with his hand in order to jar the wire. As he carried out the 1st jar, the tool string, which weighed 130kg, dislodged from a hung up point in the wellbore and dropped a further 2-3ft. This caused the wire at surface to come under tension and spring upwards 3ft causing the IP's right foot to move upwards, which in turn caused him to twist and fall over.

The IP's resulting injury was a double fracture to the lower leg. 


What Caused it:

  • Risk awareness / hazard perception by wireline crew as to potential stored energy in wireline

  • Requirement to hand jar was not considered when placing equipment on site

  • Wire line impact on the injured person lower leg caused the stored kinetic energy from the wire to travel through his leg, resulting in a double fracture to his tibia/leg bone

  • Operator placed foot on top of wire to assist in jarring operations


Corrective Actions Taken:

  • Vendor's procedures amended to include a statement on correct body position for hand jarring operations

  • Specific hand jarring risk assessment added to permit pack and permit to work system

  • Improved training on the risks associated with hand jarring

Good Practice Guidance: 
  • Site / task specific risk assessment to be carried out by the team prior to commencing hand jarring

  • Only hands to be placed to on wire during jarring operations

  • No other body part (including legs) to be place on, over or under the wire

  • Jarring only to take place between unit and bottom sheave and not in the vertical position

  • Operator to be in a position to pull wire back so that a sudden tension will result in the wire moving away from the operator

  • Operator to be positioned a safe distance from the sheave to prevent entrapment with sheave

  • Suitable level work site for operators free of potential tripped hazards to be provided


Causes and consequences of incident or accident: 
Moving, flying or falling object
Slip, trip or fall on same level
Contributing factor: 
Control of work
Contact Details (Optional): 
Colin Esslemont, Wells HSE Lead, Centrica Exploration & Production