Guidelines for the

Safe Operation of
Tubing Conveyed
Perforating Systems

EXP002  – Fire and Explosives 1

Revised May 2007
  

Table of Contents
 
1.0 Scope and content ............................................................................................................. 4
2.0 Definitions................................................................................. Error! Bookmark not defined.
3.0 Downhole equipment ....................................................................................................... 6 
3.1 Detonators and initiating devices ............................................................................. 6
3.2. Downhole firing systems ......................................................................................... 6
3.3 Other downhole equipment ...................................................................................... 7
4.0 Field Safety Procedures ................................................................................................ 7 
4.1 Service representative qualification.......................................................................... 7
4.2 Records and procedures........................................................................................... 8
4.3 Transportation.......................................................................................................... 8
4.4 General practices ..................................................................................................... 8
4.4.1 Shop loading..................................................................................................... 8
4.4.2 Pre-job safety meeting at the well site .............................................................. 8
4.4.3 Well site loading/unloading of explosive devices............................................ 10
4.4.4 Post job operations ........................................................................................... 11
5.0 Mechanical and Hydraulic Tubing Conveyed Operations ................ 12 
5.1 Gun make-up ......................................................................................................... 12
5.1.1. Supervision..................................................................................................... 12
5.1.2 Personnel safety.............................................................................................. 12
5.1.3 Avoiding explosive component impacts/mechanical interference................. 12
5.1.4. Gun arming — mechanical and hydraulic arming and firing sequence......... 12
5.1.5. Gun arming/firing bottom-up ......................................................................... 13
5.1.6 Gun detonation ............................................................................................... 13
5.2 Recovery of the gun from the well ........................................................................ 13
5.2.1 Supervision of gun recovery .......................................................................... 13
5.2.2 Drop bar.......................................................................................................... 13
5.2.3 Notification to lease owner/operator .............................................................. 13
5.2.4 Personnel safety.............................................................................................. 14
5.2.5 Gun disassembly ............................................................................................ 14
5.2.6 Internal pressure ............................................................................................. 14
5.2.7 Disassembly ................................................................................................... 14
5.3.8 Misfires........................................................................................................... 14

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Revised May 2007
  

6.0 Electrical tubing conveyed operations ............................................................. 15 

6.1 Well site preparation.............................................................................................. 15
6.1.1 Warning signs................................................................................................. 15
6.1.3 Eliminating sources of stray electrical energy ............................................... 15
6.2 Pre-Checks............................................................................................................. 16
6.2.1 Checking system circuits................................................................................ 16
6.2.2 Checking detonators...................................................................................... 16
6.2.3 Stray voltage check ....................................................................................... 16
6.2.4 Personnel....................................................................................................... 16
6.3 Gun/explosive tool arming sequence................................................................... 17
6.4 Running gun/explosive device into well ............................................................... 17
6.4.1 Restoring power ............................................................................................. 17
6.4.2 Descent ............................................................................................................ 17
6.5 Gun detonation ...................................................................................................... 18
6.6 Recovery of guns/devices from the well ............................................................... 18
6.6.1 Recovery......................................................................................................... 18
6.6.2 Powering down ............................................................................................. 18
6.6.3 Personnel ........................................................................................................ 18
6.6.4. Internal pressure ............................................................................................ 18
6.7. Disarming misfired devices ................................................................................. 18 
7.0 Special provisions............................................................................................................. 19 
7.1 Snubbing operations .............................................................................................. 19
7.2 Coiled tubing operations...................................................................................... 19

For more information...................................................................................................................... 19

EXP002  – Fire and Explosives 3

Revised May 2007
  

1.0 Scope and content  

These Guidelines are intended to promote consistent operating

practices within the perforating industry by describing good practices
and procedures for Tubing Conveyed Perforating (TCP) operations.
The Guidelines are also meant to help employers and workers comply
with regulatory requirements.

These Guidelines are based on industry best practices, experience and

engineering judgment. They must be applied using sound technical
knowledge and decision-making.

Developed by the Petroleum Services Association of Canada (PSAC),

these Guidelines have been accepted by Alberta Employment and
Immigration as recommended practices that should be followed in
order to comply with Alberta’s Occupational Health and Safety Act
and regulations. Companies performing TCP operations are expected
to establish detailed policies and procedures that cover all aspects of
TCP for use by their workers. These policies and procedures should
describe safety measures that are equivalent to or exceed those
described in these Guidelines.

Alberta Employment and Immigration gratefully acknowledges

PSAC’s contribution to promoting safe work practices and the
preparation of these Guidelines.

These Guidelines were originally published in

1992 as a booklet but never reprinted. They have
been updated and are now presented as a Safety
Bulletin.
 

EXP002  – Fire and Explosives 4

Revised May 2007
  

2.0 Definitions
approved — refers to current applicable regulations as outlined in
provincial or federal legislation governing the handling of explosives;

arming — installing a detonating device into an explosive assembly

i.e. a perforating gun assembly;

booster — an explosive device used with detonating cord or primer-

cord to transfer the detonation train from one device to another i.e.
detonator to primer-cord end, or primer-cord end to primer-cord end;

gun (gun assembly) — a carrier designed to transport perforating

charges into the wellbore;

gun spacer — a spacer used to separate the firing mechanism from

the top perforating charge or to provide a space between two
perforating intervals;

lease owner/operator — a person, partnership, company or group of

persons who, under contract and agreement of ownership, direct the
activities of one or more employers involved at a work site;

licensed qualified representative — a person holding a valid blaster’s

permit;

perforating — the use of shaped explosive charges to perforate well

casing to allow the flow of oil and/or gas into the wellbore;

service company — a person, corporation or association that is

contracted to supply, sell, offer or install a product or service to
another company, usually the owner of the work site;

snubbing — the act of moving tubulars into or out of a wellbore when

pressure is contained in the well through the use of stripping
components or closed blowout preventers (BOPs) and mechanical
force is required to move the tubing in order to overcome the
hydraulic force exerted on the tubular in the wellbore;

EXP002  – Fire and Explosives 5

Revised May 2007
  

Tubing Conveyed Perforating (TCP) — perforating guns that are run

on pipe, including tubing strings, drill pipe and coiled tubing. TCP
guns are fired by dropping a drop bar or can be pressure activated
once in position.

3.0 Downhole equipment

This section presents information about the various types and
recommended safety features of downhole equipment used in TCP
operations.

3.1 Detonators and initiating devices

3.1.1 Only high energy type electric detonators and initiators

offering protection against stray current/voltage and
radiofrequency (RF) energy are to be used. These
detonators/initiators must incorporate at least one of the
following features:
ƒ minimum DC resistance of 50 ohms and minimum “no-
fire” current of 200 milliamps
ƒ exploding bridge-wire (EBW) design
ƒ exploding foil initiator (EFI) design

3.1.2 Electric detonator/initiator lead wires must not pull out of the
detonator when pulled with 5 kilograms force (or less) tension
between the detonator body and the wires.

3.1.3 Percussion style detonators/initiators must be able to sustain a

minimum impact of 0.7 kilogram-metre (5 foot-pound)
without actuating.

3.1.4 Detonators/initiators must not contain any exposed primary

high explosive e.g. lead azide, etc.

3.1.5 Specifications for the temperature and pressure rating of

detonators exposed to the wellbore must be based on tests that
simultaneously apply temperature and pressure.

3.2. Downhole firing systems

3.2.1 Downhole firing systems must have at least two independent

safety features designed to prevent inadvertent actuation of the
detonator/initiator.

EXP002  – Fire and Explosives 6

Revised May 2007
  

 
3.3 Other downhole equipment

3.3.1 Downhole systems that require the detonator to be electrically

connected while at the surface must be of a type that
(a) the detonator can be armed electrically before being armed
ballistically, or
(b) the detonator/initiator must incorporate at least two
independent safety features that prevent inadvertent
actuation.

3.3.2 Tool designs must be such that upon retrieval from the
wellbore, trapped pressure can be safely bled down. Threaded
connections must incorporate a feature that vents trapped
pressure.

3.3.3 Radioactive marker subs must be handled by a representative

of the supplier when running the radioactive marker and when
retrieving subsurface TCP equipment. Radioactive markers
must be marked with the service company’s name and
telephone number.

3.3.4 When using a gun spacer, the service company must have
written procedures in place for its proper use and specific
safety features.

4.0 Field Safety Procedures

This section contains guidelines for the safe handling, transportation
and operation of explosive devices used in connection with TCP
operations.

4.1 Service representative qualification

4.1.1 The service company representative performing TCP

operations must hold a valid “Oil/Gas Well Perforating”
Blaster’s Permit as required by Alberta’s Explosive Safety
Regulations.

EXP002  – Fire and Explosives 7

Revised May 2007
  

4.2 Records and procedures

4.2.1 The lease owner/operator must keep adequate well records on

file while TCP equipment is in the well. The records must
include the name(s) of the supplier/manufacturer of the TCP
equipment. The supplier/manufacturer must provide written
safe use procedures, including those to be followed when
retrieving, disarming and disassembling TCP components.
Documentation provided by the supplier/manufacturer must
also include an emergency response number.

4.3 Transportation

4.3.1 The requirements of the Explosives Act (Canada), the

Dangerous Goods Transportation and Handling Act, the
regulations made under these Acts, and all other applicable
provincial regulations and municipal by-laws must be
followed at all times during the transportation of explosives
by road, air or water.

Readers should refer to PSAC’s “Perforating Industry Code of

Practice” for recommended practices involving the transportation
of perforating guns in attended and unattended vehicles.

4.4 General practices

 
4.4.1 Shop loading

Perforating equipment must be loaded in designated shop

areas and in accordance with applicable regulations.
Readers should refer to PSAC’s “Perforating Industry Code of
Practice” for recommended practices involving the loading of
perforating guns and their storage. (See “For more
information”)

4.4.2 Pre-job safety meeting at the well site

A pre-job safety meeting involving representatives of the lease

owner/operator and the service company providing TCP
services must be held before starting any TCP operations.

EXP002  – Fire and Explosives 8

Revised May 2007
  

The following topics must be discussed:

(a) Identification of well site hazards

Identify safety hazards associated with the well site,

particularly those hazards that affect the ability of workers
to safely handle and operate the explosive devices being
used. All reasonable steps must be taken to remove any
safety hazards identified during the pre-job safety meeting.
The hazards must be removed before starting the TCP
operation.

The scope of the work to be done must be explained to all

parties involved. The authorized blaster has control and
authority over the explosive devices being used.

(b) Smoking areas/open flames

Identify (by appropriate signage, markings, etc.) and

enforce the use of designated smoking areas. Smoking
must not be permitted except within the designated areas.
Smoking materials in use must remain within the
designated areas at all times.

No open flames or flame producing device are permitted

within 15 m (50 ft) of operations involving explosives.

(c) Temporary explosive location(s) facilities

Establish and inspect approved location(s)/facilities for the

temporary storage of explosive materials. These
location(s)/facilities must be located away from sources of
heat, impact/shock hazards, and any living
accommodations by a distance specified by current
applicable regulations.

(d) Explosive packaging/identification

Explosive materials arriving at the well site are to be properly

packaged and clearly labelled in accordance with current
applicable regulations.

EXP002  – Fire and Explosives 9

Revised May 2007
  

(e) Establish gun loading/make-up site

Establish the location where guns will be loaded, if

applicable, and where guns will be made up.

4.4.3 Well site loading/unloading of explosive devices

4.4.3.1 Designated site

Explosive devices must only be loaded within the designated

site. The loading site must be located at least 15 m (50 ft) or
more (as required by current applicable regulations), from any
source of heat or open flames e.g. welding activities.

4.4.3.2 Warning signs

Signs reading “DANGER EXPLOSIVES” or “CAUTION

EXPLOSIVES” must be displayed at the designated site.

4.4.3.3 Personnel

Only authorized personnel may be present in the loading area

during loading operations.

4..4.3.4 Handling explosives

The following requirements apply to the handling of

explosives:

(a) Explosives must only be stored in approved packaging.

(b) Detonators and initiating devices are not permitted within

the loading area during loading.
(c) Explosives are to be removed from their packaging within
the loading area and only using approved tools.

(d) Explosives are to be removed from their packaging only as

required for immediate loading. Unpacked explosives
must not be allowed to accumulate in the loading area.

(e) Only approved loading tools must be used. Only approved

detonating cord cutting devices and techniques must be
used.

EXP002  – Fire and Explosives 10

Revised May 2007
  

(f) Proper procedures must be followed when handling and

assembling explosive devices. Force must not be used to
fit explosives. Impacts, pinching, crushing and sparks
from all sources must be avoided.

(g) As soon as loading is completed, all loose, remnant,

damaged or unused explosive must be collected and
repackaged in approved storage containers. Storage
containers must be secured for shipment off the well site.

(h) Loaded guns must be stored at the designated site (see

clauses 4.4.3.1 and 4.4.3.2)

(i) A handling cap, plug or other closure device must always

be installed in the ends of hollow carrier-type loaded guns
during handling, transportation, and/or storage. The
closure device must have a feature that will relieve
pressure from within the gun in case of fire or excess heat.
Guns or devices with exposed detonating components —
such as the expendable or strip types — must be protected
from damage.

4.4.3.5 Housekeeping

Remnant explosives must not be mixed with ordinary trash.

Clean up must happened immediately after loading. Waste

materials, including empty explosive packaging, must be
removed from the well site for proper disposal.

4.4.4 Post job operations

4.4.4.1 Handling remnant explosives

All remnant explosives such as pieces of detonating cord,

defective or damaged charges, and misfired detonators and
packaging must be placed into proper shipping containers for
transportation off the well site (see clause 4.3).

EXP002  – Fire and Explosives 11

Revised May 2007
  

4.4.4.2 Disposal of trash

All trash and debris associated with the operation, including

empty containers or packaging, spent gun tubes and the like,
must be collected and placed in appropriate containers for
transportation off the well site.

5.0 Mechanical and Hydraulic Tubing Conveyed

Operations
5.1 Gun make-up

5.1.1. Supervision

Gun make-up is to be supervised by a licensed qualified

representative designated by the company supplying the TCP
services.

5.1.2 Personnel safety

All personnel not associated with the TCP operations must be

moved to a safe location. All personnel must be removed from
the line of fire during the arming process.

5.1.3 Avoiding explosive component impacts/mechanical interference

When making a vertical gun connection, the handling cap

must be removed from the suspended gun before it is removed
from the lower section. Immediately before connection,
ensure that no material or objects that could interfere with the
connecting process are present within the gun end cavities.

The explosive connection at tandem subs must be assembled

in such a manner as to ensure that the detonating cord and
boosters are not by-passed or exposed to the risk of being
crushed.

5.1.4. Gun arming — mechanical and hydraulic arming and firing

sequence

The service company providing TCP services must have

written arming procedures specific to the type of mechanical
or hydraulic firing system being used.
EXP002  – Fire and Explosives 12
Revised May 2007
  

5.1.5. Gun arming/firing bottom-up

Only firing heads demonstrated by design to prevent

accidental firing when exposed to wellbore conditions during
gun installation shall be installed at the bottom of the loaded
gun assembly. The use of this configuration must be jointly
reviewed and approved by the service company and lease
owner/operator.

5.1.6 Gun detonation

A licensed qualified representative of the service company

that provided the TCP system must be on location to detonate
the perforating guns.

5.2 Recovery of the gun from the well

5.2.1 Supervision of gun recovery

A licensed qualified representative of the service company

providing the TCP system must be on location while guns are
being recovered from the well.

5.2.2 Drop bar

The drop bar must be retrieved before a gun is brought to the

surface, unless there is positive indication that the gun has
fired.

The service company providing the TCP system must have

written procedures in place for the safe recovery of TCP
equipment in the event that the drop bar cannot be recovered.

5.2.3 Notification to lease owner/operator

The service company providing TCP services must make the

lease owner/operator aware that
(a) a licensed qualified representative of the service company
must be on location to detonate the perforating guns and
while guns are being recovered from the well, and
(b) written procedures must be in place for the safe recovery
of TCP equipment in the event that the drop bar cannot be
recovered.
EXP002  – Fire and Explosives 13
Revised May 2007
  

5.2.4 Personnel safety

All personnel not associated with the TCP operation must be

moved to a safe location. All personnel must be removed from
the line of fire during the disarming process.

5.2.5 Gun disassembly

The service company providing TCP services must have

written procedures in place for the safe disassembly of all
types of guns used by the company. These procedures must
address the disassembly steps to be taken in the event that the
gun has either fired or is suspected of misfiring.

5.2.6 Internal pressure

Guns such as hollow carrier guns must be checked for

evidence of internal pressure when returned to the surface. If
internal pressure is encountered, all non-essential personnel
must be moved to a safe location. The pressure must then be
bled off in accordance with the service company’s written
procedures.

5.2.7 Disassembly

The firing mechanism must be removed immediately. The gun

must then be broken down in the reverse manner to that
described in clause 5.1.3.

5.3.8 Misfires

Misfired detonating components must be immediately

removed and properly stored in an approved transportation
container.

EXP002  – Fire and Explosives 14

Revised May 2007
  

6.0 Electrical tubing conveyed operations

6.1 Well site preparation

6.1.1 Warning signs

Warning signs with the following words should be

prominently displayed at the well site and at all entrances to
the well site if initiating devices sensitive to radiofrequency
energy are in use:

“DANGER: EXPLOSIVES — TURN OFF RADIO

TRANSMITTERS”
or
“CAUTION: EXPLOSIVES — TURN OFF RADIO
TRANSMITTERS”.

6.1.2 If the initiating devices are insensitive to radiofrequency

energy e.g. exploding bridge-wire detonators or exploding foil
detonators, the warning signs need only read as:

“DANGER — EXPLOSIVES”
or
“CAUTION — EXPLOSIVES”.

6.1.3 Eliminating sources of stray electrical energy

The following sources of stray electrical energy must be

eliminated:

(a) Cathodic systems

Turn off electrical cathodic protection systems.

(b) Electric welding

Stop all electric welding operations.

(c) Radiofrequency energy

If an electric detonator is being used, ensure compliance
with the “Minimum Distance vs. Transmitter Power
Table” found in Alberta’s Explosives Safety Regulations.
The Table applies to all radiofrequency emitting devices
including radio towers, two-way portable radios and
cellular telephones.

EXP002  – Fire and Explosives 15

Revised May 2007
  

(d) Stray voltages

Before attaching ground cables, eliminate all sources of
voltage difference in excess of 0.25 volts (+/- 10%)
between the wellhead, rig and any other units. This must
be done before, and then maintained during, the arming or
disarming of any explosive device.

(e) Rig wiring

Remove or de-energize, for the duration of the entire TCP
operation, any rig electrical wiring that might come into
contact with the explosive devices.

6.2 Pre-Checks
 
6.2.1 Checking system circuits

Only an approved blasting ohmmeter can be used when

checking the continuity or insulation of a gun system.

6.2.2 Checking detonators

When detonators are being checked using an approved

blasting ohmmeter, all blasting caps, detonators and other
initiating devices must be contained within a safety loading
tube.

6.2.3 Stray voltage check

Verify that the voltage difference between the wellhead and

rig (including generator skid and barge where applicable) does
not exceed 0.25 volts (+/- 10%) before and during the arming
and disarming of any explosive device.

6.2.4 Personnel

All personnel not associated with the TCP operation must be

moved to a safe location. All personnel must be removed from
the line of fire.

EXP002  – Fire and Explosives 16

Revised May 2007
  

6.3 Gun/explosive tool arming sequence

6.3.1 All potential sources of static electricity must be grounded

using appropriate methods and non-static clothing must be
worn.

6.3.2 Confirm that all sources of stray electrical energy are

eliminated in accordance with clause 6.1.3.

6.3.3 Verify that there is no voltage difference between the points

where the blasting cap wires will be attached.

6.3.4 Remove the detonator from the approved container, making

sure that the leg wires are shunted. Insert into the detonator
safety tube, taking it to the arming area and then checking the
detonator resistance.

6.3.5 With the detonator still in the safety tube, connect the
detonator’s lead wires to those of the gun, ground connector
first.

6.3.6 Remove the detonator from the safety tube and connect it to
the detonating cord or the device to be fired.

6.3.7 Complete the assembly, taking care not to pinch, crush or

impact the explosive components.

6.4 Running gun/explosive device into well

6.4.1 Restoring power

Once the gun/explosive device is 66 m (200 ft) or more below

ground level (or sea floor if applicable), power can be restored.

6.4.2 Descent

The gun/explosive device can now be run to depth. The

gun/explosive device should be tied-in for depth control.

EXP002  – Fire and Explosives 17

Revised May 2007
  

6.5 Gun detonation

6.5.1 A licensed qualified representative from the service company

that provided the TCP system must be on location to detonate
the perforating gun.

6.6 Recovery of guns/devices from the well

6.6.1 Recovery

A licensed qualified representative from the service company

providing the TCP system must be on location while
equipment is being recovered from the well.

6.6.2 Powering down

Once the gun/explosive device is 66 m (200 ft) or more below

ground level (or sea floor if applicable), all potentially
dangerous electrical circuits i.e. battery pack, etc. must be
returned to their safe mode or removed from the well as noted
in clause 6.1.3.

6.6.3 Personnel

All personnel not associated with the TCP operation must be

moved to a safe location. All personnel must be removed from
the line of fire.

6.6.4. Internal pressure

If evidence of internal pressure is present, all non-essential

personnel must be moved to a safe location. The pressure
must then be bled off in accordance with the service
company’s written procedures.

6.7. Disarming misfired devices

6.7.1 Misfired devices must not be disarmed during a thunderstorm,

dust storm or sand storm. Disarming must not be started if
such weather is expected to arrive before the disarming
operation can be completed.

EXP002  – Fire and Explosives 18

Revised May 2007
  

6.7.2 Misfired devices must be disarmed immediately as follows:

(a) Remove the detonator from the detonating cord or device.

(b) Put the detonator in a detonator safety tube.

(c) Disconnect the detonator’s lead wires from the circuit.

(d) Shunt the detonator lead wires together. Remove the

detonator from the safety tube and place it into a container
for transportation off the well site (see clause 4.3).

7.0 Special provisions

 
7.1 Snubbing operations

If snubbing a TCP system is a possibility before or after the

guns have been fired, then a pre-job planning meeting must be
held between the lease owner/operator and the service company
that provides the system. All safety aspects of the snubbing
operation must be addressed at this pre-job meeting and proper
procedures must be agreed upon before any TCP operation
begins.

7.2 Coiled tubing operations

The requirements of clause 7.1 apply to coiled tubing

operations.

 
For more information
The Petroleum Service Association of Canada (PSAC) publishes the
Perforating Industry Code of Practice which defines safety standards
applicable to the perforating industry. Compliance with the Code is a
condition of the operating license issued by Natural Resources
Canada (NRCan) Explosives Regulatory Division, and applies to both
PSAC and non-PSAC members.

EXP002  – Fire and Explosives 19

Revised May 2007
  

Copies of the Code of Practice can be purchased by contacting:

Petroleum Services Association of Canada

#1150, 800-6th Avenue S.W.
Calgary, Alberta
T2P 3G3
Phone (403) 264-4195
www.psac.ca

EXP002  – Fire and Explosives 20

Revised May 2007
  

Contact us:
Province-Wide Contact Centre Web Site
 
 Edmonton & surrounding  www.worksafely.org
area:
(780) 415-8690  
 Throughout Alberta:
1-866-415-8690
   Deaf or hearing impaired
ƒ In Edmonton: (780) 427-9999
or
ƒ 1-800-232-7215
throughout Alberta
 
 
Getting copies of OHS Act, Regulation & Code:
 
   
Queen’s Printer Workplace Health and Safety 
 
 www.qp.gov.ab.ca  http://industry.alberta.ca/whs-ohs

 Edmonton (780) 427-4952  

 
 
 
  Call any Government of Alberta office toll-free
  Dial 310-0000, then the area code and telephone number you want to reach
 

© 2008-2009, Government of Alberta, Employment and Immigration

This material may be used, reproduced, stored or transmitted for non-commercial purposes. The source of this material must be
acknowledged when publishing or issuing it to others. This material is not to be used, reproduced, stored or transmitted for
commercial purposes without written permission from the Government of Alberta, Employment and Immigration. This material is to
be used for information purposes only no warranty express or implied is given as to the accuracy or the timeliness of the material
presented. In case of any inconsistency between this document and the Occupational Health and Safety Legislation, the legislation will
always prevail.

EXP002  – Fire and Explosives 21

Revised May 2007