Drilling Contractor Safety

Understanding the hazards associated with rod separation

An Incident

NZ September 8 2006 two drilling contractors were using pipe wrenches to separate drill rods that were extremely tight.

During this process, the hydraulic rotation of the drill string was accidentally activated

Both men were hit by the handle of a pipe wrench and knocked to the ground.

Both men suffered severe bruising.

It could have been much worse

What Went Wrong?

Mechanical tools for rod separation were available but were not used

The drillers decided to separate the rods using manual tools

The hydraulic controls were not protected from inadvertent operation

Hydraulic rotation was accidentally applied

The plan was to break this sub

sectionAway from this

section

By holding this section with one

pipe wrench

And rotating this section with another

wrench

In this direction

With the wrench in place the drill is rotated slowly anti-

clockwise to apply tension to the wrench by bringing the

handle of the wrench against the mast of the rig

Drill string rotation is

stopped but hydraulic

power remains

Drillers work in close proximity to drill string

Drillers attach pipe wrench to secure one section of the

drill string

Rotation is accidentally applied

Drill Rig (Plan)

Common practice

Drill continues to rotate and unscrew under

power

Driller holds pipe wrench in

place

High speed rotation is

applied

Drill String

Drillers work in close proximity to drill string

Danger Zone

Danger Zone while drilling

Add a pipe wrench and area increases

significanlty

A rotating pipe wrench – Easily makes contact with anyone near the controls. Maximum speed. ~1,000rpm

Why is this a major issue?

The combination of manual tools with hydraulic rotation identified as a major contributing factor

The practice is common and widespread There is an alarming history of similar incidents

from a number of industries where drill rigs are used

The following examples did not occur on URS projects

#1 Queensland – Chest Injury (Non URS) Two large pipe wrenches were used in

conjunction with a lever block to disassemble a hammer bit on a drill rig string. The handle of the wrench broke striking the drilling operator in the chest.

This is not the first time

#2 Western Australia – Chest Injury (Non URS) A driller was struck in the chest by the

handle of a pipe wrench when rotation was released following torguing up of a joint.

This is not the first time

#3 NSW – Head injury (Non URS) Two field technicians were hit on the head

by a drill rod which was being used as a pipe wrench extension handle to break drill rods

This is not the first time

#4 Western Australia – Broken Legs (Non URS) A driller received two broken legs when

rotation was applied to the drill rods with a pipe wrench attached

This is not the first time

#5 Western Australia – Abdominal Injury (Non URS) A driller received serious injuries to the

abdomen when hit with the handle of a pipe wrench

This is not the first time

#6 Pennsylvania USA – Broken Ribs (Non URS) A drillers is hit in the chest with the handle

of a pipe wrench which was attached to a drill string. The drill was rotated at full speed instead of being inched. The driller was air lifted to hospital with chest injuries.

This is not the first time

Where practicable, use mechanical means of drill rod separation (only) at all times

Where mechanical methods of rod separation are not suitable or available, eliminate the combination of manual tools with powered rotation.

Whenever manual pipe wrenches or hand tools are used to fit or remove drill rods, this must only be undertaken once the rotational power of the drill string is isolated, de-energized or positively disengaged such that intentional or accidental rotation of the drill string while pipe wrenches or tools are attached is not possible

What can be done?

What is mechanical means of drill rod separation?

Opposing Hydraulic Control

Rod Locking Devices

Rod Spanner

Hydraulic foot clamp

Hydraulic Break-out Tool

What is manual rod separation?

The use of manual hand tools (pipe wrenches) to lock or separate rods

When should you this method be used?

Only when the rotational power of the drill string is isolated, de-energized or

positively disengaged