IRP 4 2009 Well Testing and Fluid Handling

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Edi t ion 3.1

Sanction October

Date 2009

W ELL TESTI NG AND FL U I D HANDLI NG

AN I NDUSTRY RECOMMENDED PRACTI CE ( I R P )

FOR THE CANADI AN O I L AN D GAS I NDUSTRY

VOLUME 4 2 0 0 9

SANCTI ONED


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COPYRI GHT/ RI GHT TO REPRODUCE

Copyright for this I ndustry Recomm ended Practiceis held by Enform, 2009. All rights

reserved. No part of this IRP may be reproduced, republished, redistributed, stored in a

retrieval system, or transmitted unless the user references the copyright ownership of

Enform.

D I SCLAI MER

This IRP is a set of best practices and guidelines compiled by knowledgeable and

experienced industry and government personnel. It is intended to provide the operator

with advice regarding the specific topic. It was developed under the auspices of the

Drilling and Completions Committee (DACC).

The recommendations set out in this IRP are meant to allow flexibility and must be used

in conjunction with competent technical judgment. It remains the responsibility of the

user of the IRP to judge its suitability for a particular application.

If there is any inconsistency or conflict between any of the recommended practices

contained in the IRP and the applicable legislative requirement, the legislative

requirement shall prevail.

Every effort has been made to ensure the accuracy and reliability of the data and

recommendations contained in the IRP. However, DACC, its subcommittees, and

individual contributors make no representation, warranty, or guarantee in connection

with the publication of the contents of any IRP recommendation, and hereby disclaim

liability or responsibility for loss or damage resulting from the use of this IRP, or for any

violation of any legislative requirements.

AVAILABI L ITY

This document, as well as future revisions and additions, is available from

Enform Canada

5055 11 Street NE

Calgary, AB T2E 8N4

Phone: 403.516.8000

Fax: 403.516.8166

Website:www.enform.ca
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Fax 888.362.9722Enform | 5055 - 11 Street, Calgary, AB T2E8N4 | 403.516.8000

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Well Testing and Fluid Handling IRP4

October 2009 i

TABLE OF CONTENTS

Table of Contents ..................................................................... i List of Tabl es .......................................................................... iv List of Figures.......................................................................... v 4 .0 Scop e an d Con t en t s . . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . . v i

4.0.1 Purpose ....................................................................................... vi4.0.2 Audience ..................................................................................... vi4.0.3 Scope and Limitations ................................................................... vi4.0.4 Revision Process ........................................................................... vi4.0.5 Revision History .......................................................................... vii4.0.6 Sanction .................................................................................... viii4.0.7 Acknowledgement ....................................................................... viii4.0.8 Copyright Permissions .................................................................... x4.0.9 Scope ........................................................................................... x4.0.10Introduction .................................................................................. x4.0.11Symbols and Abbreviations ............................................................ xi4.0.12Abbreviations and Definitions ........................................................ xii4.0.13Common Terms of Reference and IRPs For All Operations In This Volume

xixAp pe n di x I .............................................................................. l i i

Atmospheric Fluid Scrubber Selection Guidelines ........................................ liiApp end ix I I . . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . l i i i

Pressure Rating Formula for Seamless Pipe ............................................... liii4 .1 Dr i l l Stem Testi ng .. . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . .. 1

4.1.1 Scope ...........................................................................................14.1.2 Planning a Drill Stem Test ...............................................................14.1.3 On-Site Pre-Test Guidelines ............................................................24.1.4 Drill Stem Testing Guidelines...........................................................34.1.5 Sour Drill Stem Test Guidelines .......................................................6

App end ix I I I . . . . .. . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . .. 9 Recommended Drill Stem Testing Services Inspection Checklist .....................9


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IRP4 Well Testing and Fluid Handling

ii October 2009

4 .2 W ell Test in g .................................................................. 1 3 4.2.1 Wellhead Control ......................................................................... 134.2.2 Well Testing Equipment Capacities and Pressure Ratings .................. 164.2.3 H2S Service Equipment Requirements ............................................ 214.2.4 Well Testing Equipment Material Conformance ................................ 234.2.5 Equipment Inspections ................................................................. 244.2.6 Well Testing Equipment Spacing .................................................... 254.2.7 Pre Test Equipment Check and Pressure Test................................ 284.2.8 Operational Safety ....................................................................... 304.2.9 Well Testing Workers ................................................................... 33

App end ix I V .. . . .. . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . 39 Lease Layout Schematics ........................................................................ 39Sweet Wells .......................................................................................... 40Frac Flowback with Pressure Tank Minimum Spacing Requirements .............. 40

Cold Separators Minimum Spacing Requirements ....................................... 41Heated Test Unit Minimum Spacing Requirements ...................................... 42Sour Wells ............................................................................................ 43Frac Flowback with Pressure Tank Minimum Spacing Requirements .............. 43Heated Test Unit, Pressure Tank and Closed Pressure Storage Tanks Minimum

Spacing Requirements ..................................................................... 44Heated Test Unit and Pressure Tank Minimum Spacing Requirements ........... 46

Ap pe n di x V ............................................................................ 4 7 Production Testing Services Inspection Checklist ....................................... 47

App end ix VI . . . . .. . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . 53 FLARESTACK MAXIMUM AND M I N I M U M FLARE RATES ...................................... 53Gas Exit Velocity of 50.8 mm (2) Pipe ..................................................... 54Gas Exit Velocity of 76.2 mm (3) Pipe ..................................................... 55Gas Exit Velocity of 101.6 mm (4) Pipe ................................................... 56Gas Exit Velocity of 152.4 mm (6) Pipe ................................................... 57Gas Exit Velocity from 203.2 mm (8) Pipe ............................................... 58Gas Exit Velocity from 254 mm (10) Pipe ................................................ 59

App end ix VI I . . . . .. . . . .. . . . .. . . . .. . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . 60 Hydrate Charts ...................................................................................... 60

4 .3 Oth er Flow back s .. . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . 63 4.3.1 Flowing to Open Top Tank............................................................. 634.3.2 Pumping or Circulating a Well to an Open Tank System .................... 654.3.3 Wellhead Control ......................................................................... 674.3.4 Location of The Rig Pump ............................................................. 674.3.5 Well Killing Operations ................................................................. 674.3.6 Snubbing Operations .................................................................... 704.3.7 High Reid Vapour Fluid Recovery and Handling ................................ 734.3.8 Well Site Workers Competency ...................................................... 78


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4 .4 Loading, Un lo ad ing and Transpor ta t ion o f Flu ids .. .. .. .. .. 79 4.4.1 Fluid Hauling Company Procedures ................................................ 794.4.2

Fluid Characteristics ..................................................................... 80

4.4.3 Loading, Unloading and Transportation Practices ............................. 804.4.4 Fluid Hauling Company Worker Qualifications .................................. 844.4.5 Hydrocarbon Transportation: Class & Packing Group (Boiling Point, Flash

Point & Vapour Pressure) .................................................................. 85App end ix VI I I . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . .. . . . .. . . . .. . . . .. . . . 86

B I BLI OGRAPHY ....................................................................................... 86


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L I ST OF TABLES

Well Testing Review Committee Members .................................................. ixTable 1: Flammable Limits .................................................................. xxviiiTable 2: Pressure Rating of Seamless Pipe ................................................. lvTable 2: IRP 15.3.1.5 Reserve Circulation Sand Cleanout Equipment ............ 72


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L I ST OF FI GURES

Figure 1: Code for Electrical Installations at Oil and Gas Facilities ................ 28Figure 2: Propane Saturation Curve ......................................................... 75Figure 3: Propane - Heat of Vaporization Volume Basis ............................... 76Figure 4: Liquid Vapour Chart .................................................................. 77


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4 .0 SCOPE AN D CONTENTS4.0 .1 PURPOSEThe purpose of this document is to ensure that guidelines for well testing and fluid

handling operations are in place and readily available for all personnel.

Industry Recommended Practice (IRP) 4 is intended to supplement existing standards

and regulations. It is also intended to establish guidelines in areas where none existed

previously.

4.0 .2 AUDI ENCEThe intended audience of this document includes oil and gas company engineers, field

consultants, well testing and fluid hauling personnel, other specialized well services

personnel, and regulatory bodies.

4.0 .3 SCOPE AND L I M I T A TI O NSThis IRP includes pertinent information about well testing, including the following:

Personnel Requirements

Drill Stem Testing

Loading, Unloading, and Transportation of Fluids

Operational Procedures

IRP 4 supplements existing standards and regulations, and provides guidelines and

recommendations where none existed previously. It also refers to other pertinent

standards where appropriate, and provides information on how to access them. A full list

of the documents referred to in this IRP plus other useful reference material is provided

inAPPENDIX VIII.

4.0 .4 REVI SI ON PROCESSIndustry recommended practices (IRPs) are developed by Enform with the involvement of

both the upstream petroleum industry and relevant regulators. IRPs provide a unique

resource outside of direct regulatory intervention.

This is the second revision to IRP 4. Those who have been familiar with the first two

editions of IRP 4 should take the time to review this edition thoroughly, as it has been


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completely redeveloped to address issues brought forward since the last edition by

industry and government stakeholders.

Technical issues brought forward to the Drilling and Completions Committee (DACC) as

well as scheduled review dates can trigger a re-evaluation and review of this IRP, in

whole or in part. For details on the specific process for the creation and revision of IRPs,

visit the Enform website atwww.enform.ca.

4.0 .5 REVI SI ON H I STORYIn 1988 a Well Testing and Fluid Handling Subcommittee (WTFHSC) consisting of

representatives from CAODC, CAPP, PSAC, Alberta OH&S, and the Alberta ERCB were

formed. Under the auspices of the Drilling and Completion Committee (DACC), the

WTFHSC mandate was to investigate and develop minimum recommended practices

respecting equipment, procedures and workers for the safe testing of wells and handling

of fluids. The Recommended Practice (ARP) documents were developed during well

testing and fluids handling operations at wells in Alberta; and were fully supported by the

Alberta ERCB and Alberta OH&S.

In 1999, the scope and breath of recommended practices encompasses many more

issues, companies, associations and governments. The reference to Alberta in the title of

these practices is changed to industry (IRP ) to better reflect the broader scope. Where

industry has grown to other regions of western Canada, these IRPs continue to assist

companies in their daily operations; These IRPs are intended to follow the user to any

site, anywhere in the world, as a minimum operating practice.

In 2005 IRP 4 needed a review and update to reflect the changes in industry and

legislation. With approval from DACC a new committee was formed to address the need

for a complete review and update of the document.

In 2009 IRP 4 added a new section4.3.7 High Reid Vapour Fluid Recovery and Handling

Hyperlinks were updated on all other sections.
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viii October 2009

4.0 .6 SANCTI ONThe following organizations have sanctioned this document:

British Columbia Workers Compensation Board (WorkSafeBC)

Canadian Association of Oilwell Drilling Contractors

Canadian Association of Petroleum Producers

Employment, Immigration and Industry, Alberta

Energy Resources Conservation Board, Alberta

International Intervention and Coil Tubing Association (Canada)

National Energy Board

Oil and Gas Commission, British Columbia

Petroleum Services Association of Canada

Saskatchewan Energy Resources

Saskatchewan Labour

4.0 .7 ACKNOWLEDGEMENTThis IRP under the auspices of the Drilling and Completions Committee (DACC), was

originally developed as an Alberta Recommended Practice (ARP) by the Well Testing and

Fluid Handling subcommittee, and subsequently updated by the Well Testing Committee

in 1999.

Acknowledgments of the following individuals is in recognition of their time and effort in

any and all of the meeting and work sessions, and acknowledgement of the corporate

entities that allowed these individuals to take time away from their busy desks to help

complete this project.


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October 2009 ix

Wel l T es t i ng Rev i ew Comm i t t ee Members

Name Com pany O rgan i za t i on

Represented

Craig Marshall, Chair Canadian Sub-Surface Energy Services Inc PSAC

Nicole Axelson Petroleum Services Association of Canada PSAC

Frank A Barlow Conoco Phillips Canada CAPP

Glenn Berry Enseco PSAC

Dustin Brodner Petro-Canada CAPP

Lonnie Campbell Concord Well Servicing Ltd CAODC

Bruce Cazes BC Oil and Gas Commission

Lyle Gallant Weatherford Canada Partnership PSAC

Robert Knowles Weatherford Canada Partnership PSAC

Kevin Kostrub Alberta Energy Utilities Board

Manuel Macias Enform

Lyle Nelson Grant Production Testing Services Ltd PSAC

Greg Onushko Grant Production Testing Services Ltd PSAC

Don Pack Precision Drilling Corporation CAODC

Matthew Ritchie Enseco PSAC

Colby Ruff Alberta Energy Utilities Board

Garth Sampson Weatherford Canada Partnership PSAC

David W Smith Am-Gas Scrubbing Systems (1989) Ltd PSAC

Jack W Thacker Husky Energy Inc CAPP

Emerson Vokes Lonkar Well Testing Ltd PSAC


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4.0 .8 COPYRI GHT PERMI SSI ONSThis IRP includes documents or excerpts of documents as follows, for which permission toreproduce has been obtained:

Copyr i gh t ed I n f o rm a t i on Used I n Perm i ssi on f r om

Figure 1 Page 28 Safety Code Council of Alberta

4.0 .9 SCOPEThe purpose of this series of IRPs is to enhance safety during well testing and fluid

handling operations of gas and oil wells.

4.1 Drill Stem Testing contains recommended practices for DST operations including: test

planning, as well as pre-test, post-test, and sour testing guidelines.

4.2 Well Testing details recommended practices for Well Testing operations, including:

equipment design and operation, worker requirements and qualifications, purging and

pressure testing, operational safety, and safety equipment.

4.3 Other Flowbacksaddresses recommended practices for service rig operations

involving the flowback of fluids from the well. Matters addressed include: produced

fluids, venting, well control, equipment, procedures, and well site workers.

4.4 Loading, Unloading, and Transportation of Fluidsprovides recommended proceduresfor the safe transfer of fluids from temporary and permanent production facility tanks to

trucks. The procedures emphasize sour fluids and high vapour pressure hydrocarbon

mixtures. The IRP also addresses transportation.

The practices described in the IRPs should be considered in conjunction with other

industry recommended practices, individual operators well testing and fluid handling

practices, and site specific considerations. It is recognized that other procedures and

practices as well as new technological developments may be equally effective in

promoting safety and efficiency.

4.0 .10 I NTRODUCTI ON An integral part of the exploration and development of oil and gas resources is reservoir

evaluation. Evaluation methods with the greatest inherent environmental and safety

concerns are those which remove reservoir fluids by means of drill stem testing, well

testing or any other methods of flowback.


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The avoidance of developing a combustible hydrocarbon gas/air mixture, and the safe

handling of highly volatile reservoir or stimulation fluids, and corrosive or toxic fluids are

of concern when evaluating a well.

The environmental, safety, and health risks associated with well testing and fluid

handling can be minimized by properly trained workers implementing prudent procedures

and using properly designed equipment.

4.0 .11 SYMBOLS AND ABBREVI ATI ONSASME: American Society of Mechanical Engineers

ASTM: American Society of Testing and Materials

API : American Petroleum Institute

ERCB: Energy Resource Conservation Board (formerly AEUB)

CAPP: Canadian Association of Petroleum Producers

CBM: Coalbed Mehane

CAODC: Canadian Association of Oilwell Drilling Contractors

CPA : Canadian Petroleum Association

CSA : Canadian Standards Association

CRN : Canadian Registration Number

CTU: Coil Tubing Units

DACC: Drilling and Completions Committee

DST: Drill Stem Test

ESD : Emergency Shut Down (valve)

I RP: Industry Recommended Practice

JSA: Job Safety Analysis

LEL: Lower Explosive Limit


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MAW P: Maximum Allowable Working Pressure

MSDS: Materials Safety Data Sheet

NACE: National Association of Corrosion Engineers

NORM: Naturally Occurring Radioactive Material

OEL: Occupational Exposure Limit

OH&S: Occupational Health & Safety

OEM: Original Equipment Manufacturer

PSV: Pressure Relief Valve

PSAC: Petroleum Services Association of Canada

PPE: Personal Protective Equipment

SABA: Supplied Air Breathing Apparatus

SCBA: Self-contained Breathing Apparatus

SI THP: Shut In Tubing Head Pressure

SI CHP: Shut In Casing Head Pressure

TDG: Transportation of Dangerous Goods

UEL: Upper Explosive Limit

W H M I S: Workplace Hazardous Materials Information System

4.0 .12 ABBREVI ATI ONS AND DEFI NI T I ONSAdequa t e : For the purposes of this IRP adequate is defined as the result ofconducting a hazard assessment and mitigating risks associated with the job to

be performed.

Adequa t e L igh t i n g : The visibility must be such that the worker will be able to

exit the worksite to a secure area in the event of an emergency. Flashlights, rig

lights, and vehicle lights can be considered as emergency back-up lighting.(Waiting onIRP 23 Lease Lighting Standardsadequate lighting exists when the
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site is illuminated sufficiently to ensure that the worker is able to perform routine

duties safely.)

Ref e r ences / L inks

Workers Compensation Board of British Columbia

Saskatchewan Dept of Labour, Occupational Health and Safety

NOTE: Regulations in the provinces of British Columbia and Saskatchewan

define lighting with specific measurement criteria. This should be

referred to when operating in these provinces

NOTE: Consideration must be given to additional lighting on complex

operations.

Bleed Of f : Where pressure is present in the well, or piping systems, andseparating systems and needs depressurizing is required before work cancommence.

Caut ion : Caution must be exercised on wells known to contain lower levels ofH2S or have harmful or toxic substances, have severe abrasives (e.g., frac sand),

have other unusual hazards, and are high pressure. The term cau t i on does not

categorize a well outside of Sweet or Sour.

It is intended to alert owners, employers, and workers to dangers that may

exceed those of routine sweet wells and wells with minimal H2S concentrationwhere prescriptive equipment requirements are not provided.

Cer t i f ied Pressur ized Vessel : A pressurized vessel which has been constructed

following a program of quality control, designed for the application, and isregistered with the provincial agency that applies a stamp of certification on thevessel nameplate. All vessels must have a Canadian Registration Number (CRN)

registered in all provinces of intended use.

Closed Sys tem : A closed system refers to a handling system in which the odours

or emissions from the wellbore effluent are either flared or vented to atmosphere

through an H2S scrubber, in a controlled manner.

Coi led Tub ing Un i t Opera t ion s : Coiled tubing units (CTU) are commonly usedin other flowbacks to recover wellbore effluent. Nitrogen, carbon dioxide or air isused to move and lift proppant, produced sand or stimulation fluids such as acid,

chemicals or hydraulic fracture treatment fluids from the wellbore. Coiled tubing

unit operations may also be undertaken to evaluate well production capability.

Conf ined Space: A space which is enclosed or partially enclosed. Has limited or

restricted means for entry/exit. Is not designed or intended for continuous human
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occupancy. Is or may become partially hazardous to a worker entering or that

may complicate the provision of first aid, evacuation, rescue or other emergency

response services. Refer to applicable OHS Regulations

Dr i l l i ng Com pany : An individual or company that enters into a contract with anowner of a wellsite to drill for oil and gas.

Dr i l l S tem Tes t : A method of determining the producing potential of a

formation. This is done by removing the hydrostatic pressure of the drilling fluid

column and allowing formation fluids or gas to flow into an evacuated or partiallyevacuated drill string or production string. This allows the formation pressures tobe monitored and measured to calculate flow and depletion rates. A drill stem

tester represents the company responsible for the downhole and surface

equipment used in identifying the content and production capability of theformations to be tested.

Emp loye r : Means a person, firm, association or body that has, in connection withthe operation of a place of employment, one or more workers in the service of

the person, firm, association or body.

Em er gency Shu t d ow n Dev i se Va lve: It is a hydraulically or pneumatically

operated, high-pressure valve installed on the wellhead with remote or automaticshutdowns. Its purpose is to provide a means to remotely shut in the well in anemergency. An ESD is required on wells to be flowed having a surface pressure

greater than 1379 kPa and a H2S content greater than 1% or release of one

tonne of sulfphur per day.

Flow back : Where pressure on a well is bled off and the well continues to flow,and is allowed to flow to establish a rate of gas and fluid from the well.

High Vapour Pressure Hydro carbons : Hydrocarbon mixtures with a Reidvapour pressure greater than 14 kPa or an API gravity greater than 50Oare

considered to be high vapour pressure hydrocarbons.

NOTE: Reid Vapour Pressure is determined in a laboratory test. API gravity can

be readily measured in the field. C1-C7 content can also be indicative of

a fluids flammability. Flammability increases with increasing C1-C7

content. Fluid analyses, if available should be reviewed. Fluid and

ambient temperatures should be considered.

I n l i ne Test : An inline test is c losed when well effluents measured at the test

separator are diverted to the pipeline in some occasions fluids are produced tostorage.

Mud Can: A device used to contain fluids and direct them away from the drill

pipe when breaking connections.


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Non - Cer t i f ied Pressur ized Vesse l : A vessel that does not require certification

for use in pressure applications. The vessel must have some form of pressure

relief valve (PSV). If the tank is to be used as the primary vessel, the tank must

have been constructed under a quality control program. Construction, design, andmaterial specification data must be available when requested by the well owner.Government departments may also request this data.

Caut ion : The vessel must be designed for its intended use.

Example : A vessel designed to operate below 103.4 kPa (15 psi) working

pressure does not require provincial certification from local jurisdictions

but is required to be constructed under a registered quality control

program in this IRP.

Occupat ion a l Expo sure Lim i t s Work er Sa fe ty Cons idera t ion

The Occupational Exposure Limit (OEL of H2S is, eight hour OEL: 10 ppm)

In most cases when well testing, workers are in open-air environments and workshifts longer than eight hours. Therefore planning consideration must reviewsituations when workers are exposed to short-term levels of H2S greater than

10ppm and longer-term levels less than 10ppm. The ceiling limits vary through

the various regulatory authorities. The two most common ceiling limits are 10ppm and 15ppm.

Refer to your local and federal Occupat ion a l Exposur e Lim i t s fo r Chem ica l

Subs tances for more information on exposure limits to other chemicals.


Alberta Occupational Health and Safety Act Chemical Hazards

Saskatchewan Occupational Health and Safety Act

Workers Compensation Board of British Columbia OHS & Regulation

Open Sys tem : An open system refers to a handling system, such as a rig tank,in which any gas vapours produced from fluids are vented to atmosphere in an

uncontrolled manner. This type of system requires constant monitoring to ensuretransient vapours/gas are maintained below 20% of LEL and 10 ppm H2S.

Ot he r F lowb acks : Other flowbacks refers to operations, other than production

testing and drill stem testing, in which gas or fluids are flowed or induced to flowfrom the wellbore. This includes well killing operations and the recovery of well

stimulation fluids and solids by flowing, pumping, swabbing or by the circulationof fluids (i.e., coiled tubing.) Refer toSection 4.3 Other Flowbacks for information

specific to testing.
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O w n e r : 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 worksite.

Persona l Pro t ec t ive Equ ipm ent ( PPE) : Equipment designed and used toprotect workers.

Posi t i v e Pressure : Positive pressure refers to a pressure greater than

atmospheric pressure (0 kPa gauge).

Pressur ized Truck Tank : A pressurized truck tank must comply with all the CSAB620 requirements as determined by CSA B621. If the maximum allowable

working pressure (MAWP) is greater than 101.3 kPa (15 psi) then ABSA/ASME

certification is also required. The MAWP is specified on the nameplate of mostoilfield production equipment such as all transport and pressure vessel

equipment.

Purge : Where a vessel, container or piping system is evacuated of its gas and/or

fluid contents and replaced with another gas and/or fluid. The general purpose ofpurging is to remove explosive and/or flammable fluids and gases from a closedpiping system prior to opening the system to atmosphere or prior to entry of the

system by workers. The practice of purging usually entails replacing theexplosive/flammable contents with a product that is non-explosive/flammable orto create an atmosphere with an acceptable Lower Explosive Limit (LEL) and

Upper Explosive Limit (UEL) for workers. Purging is also used to aid the removal

hazardous gases and fluids from vessels and piping systems prior to shipment ofequipment or transportation of fluids.

Qual i f ied Wel l Tes t ing Person : An individual who has had a minimum of three

months previous experience with a service company or well owner andunderstands the concept of gas and liquid separation using pressure equipment

and flaring. Without this prior experience, the individual is considered intraining. The individual must be able to provide documented evidence, when

requested, of this experience. The individual must have all certifications required

by provincial regulatory agencies and/or listed in this IRP.Section 4.2.9of this

IRP identifies the qualifications required for a well testing worker to handle

various levels of responsibility.

Supp l i ed A i r B r eat h in g Appa r a t u s ( SABA) : It consists of a small air cylinder(less than 5 minutes of breathing air) and air mask intended to be carried on thehip of a worker with the ability to connect, by hose, to numerous larger air

cylinders. This type of configuration is used for extended work periods where aworker is exposed to an H2S or other hazardous breathing environment.

Sel f -Cont a ined Brea th in g Appara tu s (SCBA) : It consists of an air cylinder

and mask intended to be carried on the back of the worker and has (+)(-) 30minutes of breathing air contained in the cylinder. This device is used for short

work periods where a worker is in an H2S or other hazardous breathing


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environment. Also used for emergency situations to aid in the rescue of injured

personnel.

Safe ty Serv ice Com pany : A company that provides one or more of thefollowing: equipment, workers, training, and neutralising chemicals to reduce therisk to onsite workers and equipment during various well operations.

Sa f e t y S t andby Me t h od : Where a person outside of the hazardous area

monitors the work of persons inside the hazardous area, with no other purpose

than to monitor personnel and their safety equipment, and implement rescueprocedures when necessary.

Serv ice Com pany : Means a person, corporation or association who is contracted

to supply, sell, offer or expose for sale, lease, distribute or install a product orservice to another company, usually the owner of the worksite.

Shu t I n Tub ing Head Pr essu r e ( SI THP) : The pressure at surface on the

tubing in the well.

Shut I n Cas ing Head Pressure (S I CHP) : The pressure at surface on the

casing in the well.

St imu la t i ons : Stimulations are operations designed to improve well production

capability or, in the case of injection or disposal wells, to improve the ability of awell to accept fluid. These operations may include the use of hydrocarbon andwater based fracturing fluids, acids, various chemicals, and proppants.

Swabb ing : Swabbing is an operation conducted to reduce the hydrostaticpressure of the fluid in the wellbore to initiate flow from a formation.

Sw ive l Jo in t ( Ch iksan ) : A series of short steel pipe sections that are joined by

swivel couplings. The unit functions as a flexible flow line that provides a flow

path between the control head and the floor manifold.

Test L ine: A flow line from the drill stem tester's floor manifold to move fluid orgas to flare, test separator or storage.

Stabb ing Va lve : A full opening safety valve that can be installed to the top of

any joint of pipe being pulled out of or inserted into the well to prevent flow upthe pipe and out to atmosphere.

W el l K i l l i ng Oper a t i ons : Well killing operations are operations in which well

effluent is circulated from the wellbore using a fluid of sufficient density to

prevent further influx of reservoir fluids. The process is continued until the well isincapable of flow.


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Ref e r ences/ L inks

Section IRP 4.2 Well Testing

IRP 6.0 Critical Sour Underbalanced Drilling

W o r k e r : Means a person who is engaged in an occupation in the service of anemployer.

Under ba lanced Dr i l l i ng : Entails allowing a well to flow oil, gas, and formationfluids to surface as it is being drilled as opposed to conventional or overbalanceddrilling where one of the prime considerations is in preventing hydrocarbons from

flowing during the drilling process.


IRP 6.0 Critical Sour Underbalanced Drilling

Alberta Energy and Utilities Board Interim Directive ID94-3 and Directive 36,

Section 10, 20, 23, 24

4.0 .13 COMMON TERMS OF REFERENCE AND I RPS FOR ALL OPERATI ONSI N THI S VOLUME

4.0.13.1 Respons ib i l i t i es o f Ow ners and Serv ice Con t r acto r sIRP The wellsite owner is responsible for all activities on a lease. The safety

of on-site workers and environmental protection take precedence over

well testing data requirements. Owners shall maintain general health

and safety at the well site by coordinating all activities and ensuring

proper equipment, materials, and workers are provided to accomplish

the program and to satisfy all applicable regulatory requirements.

IRP The well site owner shall ensure the following breathing equipment is

provided as a minimum:

On all wells, regardless of designation, two Self-Contained Breathing Apparatus(SCBA) must be on location at all times. (Additional SCBA may be required as per

local authorities).

When well testing wells where the H2S concentration is greater than 100

ppm, the owner must provide supplied air breathing apparatus (SABAs)

in addition to the self-contained breathing apparatus (SCBA). As a

minimum this package must contain an adequate air supply system
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complete with air cylinders, manifold, work lines and egress packs

(SABAs) and a minimum of two back packs (SCBAs).

On simple well-servicing operations (such as rod jobs, tubing changes,bleed-offs, plug retrieval, abandonments, swab cleanouts) where the

H2S concentration is greater than 10 ppm and where the venting of gas

to atmosphere is minimal and the bleed-off period is short in duration

and where more than two workers are present at the same time, an

additional two back packs would be adequate instead of a supplied air

system. (This does not apply to well testing.) Therefore a minimum of

four back packs are required on the well site. Two of the back packs

must be designated for emergency use only. The other packs are for use

by workers where breathing equipment is necessary to complete

operational tasks. Protection for the workers on the site and nearby

residents, from over-exposure to H2S, must be maintained whenconsidering this option.

IRP Refer to CSA stan dard CSA-Z94.4-0 2 Se lec t ion , care and use o f

r esp i r a t o r y equ ipmen t .

IRP Where an owner representative is assigned to the site, the

representative shall be present during all operations where gas will be

vented from open tank systems. Where an owner representative is not

assigned to the site, the contractor assigned to flow the well to open

tank systems must have a supervisor present during the operation.

IRP The owner shall ensure a gas detection meter is available to the site

workers and that they are properly trained in the use and operation of

the meter.

IRP The owners representative shall have a trained and competent person

onsite in the operation of an LEL meter. The owners representative

shall ensure availability of an LEL meter on all sites. (ReferenceIRP 7

Standards for Wellsite Supervision of Drilling, Completions and

Workovers, Alberta ERCB BM 033, CAPPFlammable Environments

GuidelinesandIRP 18 Upstream Petroleum Fire and Explosion Hazard

Management)
http://www.enform.ca/publications/IRP/standards_for_wellsite.aspxhttp://www.enform.ca/publications/IRP/standards_for_wellsite.aspxhttp://www.enform.ca/publications/IRP/standards_for_wellsite.aspxhttp://www.enform.ca/publications/IRP/standards_for_wellsite.aspxhttp://www.enform.ca/publications/IRP/standards_for_wellsite.aspxhttp://www.capp.ca/library/publications/healthSafety/pages/pubInfo.aspx?DocId=81688http://www.capp.ca/library/publications/healthSafety/pages/pubInfo.aspx?DocId=81688http://www.capp.ca/library/publications/healthSafety/pages/pubInfo.aspx?DocId=81688http://www.capp.ca/library/publications/healthSafety/pages/pubInfo.aspx?DocId=81688http://www.enform.ca/publications/IRP/fire_and_explosion.aspxhttp://www.enform.ca/publications/IRP/fire_and_explosion.aspxhttp://www.enform.ca/publications/IRP/fire_and_explosion.aspxhttp://www.enform.ca/publications/IRP/fire_and_explosion.aspxhttp://www.enform.ca/publications/IRP/fire_and_explosion.aspxhttp://www.enform.ca/publications/IRP/fire_and_explosion.aspxhttp://www.capp.ca/library/publications/healthSafety/pages/pubInfo.aspx?DocId=81688http://www.capp.ca/library/publications/healthSafety/pages/pubInfo.aspx?DocId=81688http://www.enform.ca/publications/IRP/standards_for_wellsite.aspxhttp://www.enform.ca/publications/IRP/standards_for_wellsite.aspxhttp://www.enform.ca/publications/IRP/standards_for_wellsite.aspx


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IRP The owner shall or instruct the service contracting company to:

Provide signage ordering vehicles to stop at the lease entrance on

all sites where gas is being vented to atmosphere

Ensure there are an adequate number of qualified workers on the

well site at all times to conduct operations safely

Provide fluid hauling companies with shipping documents such as a

waste manifest that describes the properties and potential hazards

associated with fluids to be transported in appropriate

Transportation of Dangerous Goods (TDG) terms


Transport CanadaTDG Act, Sections 5, 6, 8 & 14.

Transport CanadaTDG Regulations, Part 3.

Transport CanadaTDG Act, Section 40(Clear language).

Ensure fluid hauling workers are oriented to site-specific procedures

Ensure sour fluids are transported during normal hours of operations

unless special arrangements and precautions have been made between

the owner and the truck operator. This may include standby workers,

equipment, and monitoring devices

Ensure appropriate safety equipment (i.e., H2S monitor, explosive

mixture monitor, and respiratory protective equipment) is available

Maintain a contingency plan including procedures for truck loading,

unloading, and transportation-related spills.

IRP The owners representative is responsible for conducting an on-site pre-

job equipment inspection to ensure the equipment is operational and as

ordered.

IRP Owners shall prepare a program of operations. The program shouldinclude but not be limited to:

The purpose of the operation

Relevant well data

Identify any potential hazards
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Equipment requirements and layout having regard for pressures and

flows expected

Environmental and safety considerations, relative to on-site workersand the public

Special procedures to be employed

Emergency contacts

Minimum worker requirements and qualifications

Test objectives

Test sequence in appropriate detail

Technical contact in case of unexpected program deviations

Emergency response plan, contacts and procedures

Shall ensure the program is available for viewing by all participating

contractors prior to job commencement.

IRP The prime contractor shall ensure that their representative is able to

provide competent and effective supervision of the operations being

carried out. The owners representative shall have the following:

For well site supervision of drilling completions and workovers, the

prime contractors representative must be certified inIRP 7Standards for Wellsite Supervision of Drilling, Completions and

Workovers

First Aid Certificate

If well servicing, an appropriate blow-out prevention (BOP)

certificate

If drilling, an appropriate blow-out prevention (BOP) certificate

H2S Training and Certification for sour wells ( > 10 ppm)

Transportation of Dangerous Goods Certificate where hazardousmaterials will be shipped

WHMIS training

Complete awareness of IRP 4Well Testing and Fluids Handling as

they pertain to the operation being carried out and a full
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understanding of the hazards related to the physical properties of

the fluid being handled, prior to conducting the operation

Shall make available and be competent in the operation ofequipment used to detect hazardous or explosive mixtures

An understanding of section 8.110 of the ERCB Regulations when

hydrocarbon mixtures with a Reid vapour pressure greater than 14

kPa or with an API gravity exceeding 50 degrees, are encountered

4.0.13.2 Dr i l l i ng Serv ice Com pany Respons ib i l i t i esIRP The drilling service company shall ensure that all required rig workers

are available during operation and that the workers are physically

capable and have been properly trained to carry out their designatedresponsibilities. The drilling service company shall ensure that the

equipment and facilities it is contracted to supply are available during

operation and it is designed for the parameters of the project. Pressure

test certification, material inspections, and sour service specifications

shall be made available when requested.

4.0.13.3 Dr i l l S tem Tes t ing Com pany Respons ib i l it i esIRP The drill stem testing company shall ensure that the workers it provides

are available during the drill stem test, the workers are physically

capable, and have been properly trained to carry out their designatedresponsibilities during the drill stem test at the worksite. The drill stem

testing company shall ensure that the equipment and facilities it is

contracted to supply are available during the drill stem test, are in good

working order and is designed for the parameters of the project.

Pressure test certification, material inspections, and sour service

specifications shall be made available when requested.

4.0.13.4 Safety Serv ice Com pany Responsib i l i t iesIRP The safety service company shall ensure that the workers it provides are

available during operations, the workers are physically capable, and

have been properly trained to carry out their designated responsibilities.

The safety service company shall ensure that the equipment it is

contracted to supply is available during the operation, is in good working

order, and is designed for the parameters of the project. The safety

service company must ensure proper equipment for respiratory

protection, H2S gas detection, breathing-air supply, determining


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explosive limits, and neutralising chemicals is in sufficient quantities at

the worksite. Consideration should be given to having spare H2S and

LEL meter.

The safety service company must provide training of all workers on the

worksite in the specific use of this equipment as required.

4.0.13.5 Wel l Tes t ing Com pany Respons ib i l i t i esIRP The well testing company shall ensure their employees are physically

capable to carry out their designated responsibilities during the

operation. Well testing personnel must carry certificates of training with

them. The well testing company shall ensure the equipment and

facilities it is contracted to supply are designed and suited for the

application. Pressure test certification, material inspections, and sour

service specifications shall be made available when requested.

4.0.13.6 Flu id Hau l ing Com pany Respons ib i l it i esIRP Fluid hauling companies shall ensure the workers it provides are

available during the operations, the workers are physically capable to

carry out their designated responsibilities, and the workers carry

certificates of training with them. The fluid hauling company shall

ensure that the equipment and facilities it is contracted to supply are

available during the operation, are in good working order, and aredesigned for the parameters of the project. Pressure test certification,

material inspections, and sour service specifications shall be made

available when requested.

4.0.13.7 Wel l Designa t i on f o r Work e r Safe t y i n H 2S Env i r onm entsIRP Sweet and Sour designations are used by industry and legislative bodies

as a reference for administrative purposes. For technical purposes

specific concentrations of hydrogen sulphide will dictate appropriate

equipment requirements to conduct a task safely, maintaining the

health and safety of the worker while ensuring the integrity of theequipment. The well designations of this IRP are centred on hydrogen

sulphide (H2S) content, which through inhalation, is the most frequently

encountered hazardous substance by well testing workers. There may

be other substances as onerous for maintaining worker safety and must

be considered when planning work programs. Provincial Occupational

Health and Safety Acts define the exposure limits for numerous

substances. Those documents should be referred to when substances


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other than hydrogen sulphide (H2S) are known to be present at the well

site. The well designations in this IRP are designed for worker safety

when working in hydrogen sulphide (H2S) environments.Sweet Well

10 ppm hydrogen sulphide content or less: Designated as sweet.

A well with a hydrogen sulphide (H2S) content of 0.01 moles / kilomole

(10 ppm) or less is designated as sweet.

The hazards of sweet gas to the worker, from exposure or inhalation,

are less than those imposed by sour gas and therefore require a

minimum of two SCBAs on all wells to aid in protecting the worker.

Other requirements are detailed throughout these IRPs. Material

specifications relative to metallurgy for equipment used to flow wells

containing zero H2S content are not as stringent as those required forwells containing H2S.


Section 4.2 Well Testing

NACE (National Association of Corrosion Engineers)

ASME B31.3

4.0.13.7 .1 . Sour We l l More than 10 ppm hydrogen sulphide content: Designated as sour .

Any well with a hydrogen sulphide (H2S) concentration greater than

0.01 moles/ kilomole (10ppm) is designated as sour .

Sour gas hazards relative to worker safety requires specific equipment

to protect the worker.

Prescriptive guidelines for the quantity and use of breathing equipment

to protect the worker are outlined in this IRP and other provincial

regulations.

Additionally, gas, containing H2S, is more corrosive to metals and thus,

requires precautions when selecting equipment to perform well testing

operations.

Section4.2.3 H2S Service Equipment Requirementsof this IRP provides

guidelines relating to equipment selection for use in H2S environments.
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Section 4.2 Well Testing

Provincial Occupation Health and Safety Acts

Alberta Chemical Hazards RegulationSections 2 & 9

NACE MR 01-75 LATEST EDITION

ASME B31.3

4.0.13.7 .2 . Cri t ica l Sour W el l Critical Sour Wells are defined by appropriate Provincial Regulatory

Agencies.

They generally include all the elements of a sour well plus an amplified

concern for residents in close proximity to the well site along with

environmental issues.

In AlbertaDirective 071: Emergency Preparedness and Response

Requirements for the Petroleum Industry

4.0.13.8 Meta l lu rgy cons ide ra t ions fo r H 2S env i ronmen t s H2S affects the integrity of metals not designed for use in H2S

environments.

Other elements such as CO2 also have corrosive affects on metals. The

requirement for special metallurgy in equipment is not related to a sour

designation of a well.

It is related to H2S Partial Pressure and Sulphide Stress Cracking as

defined by the National Association of Corrosion Engineers (NACE).


Section 4.2.3 H2S Service Equipment Requirements

NACE MR 01-75 LATEST EDITION specifications
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4.0.13.9

Gas De tec t ion Mon i to r ing fo r Exp los ive and Flam m ab le Lim i ts( Fu r th e r i n f o rm a t i on seeI RP 18- Fire and Explosion Hazard

Management)

IRP The owners site representative must be trained and competent in the

use of gas detection meters. The site representative must possess or

make available at the wellsite, a gas detection meter capable of

measuring LEL.

IRP Where the owner does not have a site representative, the owner shall

ensure a gas detection meter is available to the site workers.

IRP One person per shift must be trained and competent in the use of gas

detection meters where gas vapours will be vented to atmosphere or

there is a potential of gas vapours to be released to the atmosphere. All

users must be properly trained and competent.

IRP No worker shall enter the 50 metre sa f et y zone around an open tank

system where gas vapours have been vented to atmosphere until

cleared to do so by the owners site representative or the worker who is

responsible for monitoring the area with a gas detection meter.

NOTE: Refer toSection 4.3 Other Flowbacks, for more detail on the

requirement of gas detection and flowing wells to open tank systems.

I n t r o d u c t i o n : Gas detectors have become an everyday part of equipment

requirements on an oil and gas site. There must be accurate methods of detecting

the absence or presence of various gases, so the workplace can be maintained

safe and productive.

Exp los i ve o r F lamm ab i l i t y L im i t s :

The term limits of flammability or explosive limits, refers to the percentage by

volume of a fuel in a fuel/air mixture which will burn. The flammable rangespreads between the lower flammable limit and the upper flammable limit. Fuel

/air mixtures outside the flammable range will not burn or explode.
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Flammable limits for some common flammable gases and vapours are in listed

below.

T ab l e 1 : F l amm ab l e L i m i t s

Exp los ive

L im i t s ( % b y

vo l . I n a i r )

LEL

UEL

Flash Point

Degrees

Cels ius

Vapour

Dens i t y A i r

= 1 .0

I g n i t i on

T emp .

Degrees

Cels ius

Ammonia 15.0 28.0 Gas 0.58 630

Butane 1.8 9.0 Gas 2.0 410

Carbon Monoxide 12.5 74.0 Gas 0.97 570

Diesel 0.3 10.0 52 > 3.0 < 171

Ethane 3.0 12.5 Gas 1.0 472

Hydrogen Sulphide 4.0 45.0 Gas 1.19 260

Ethyl Alcohol 3.3 19.0 +13 1.59 365

Methanol 6 7.6 16c 1.1 464

Methane 5.0 15.0 Gas 0.55 538

Propane 2.2 10.0 Gas 1.5 450

Toluene 1.3 7.0 +4 3.14 535

Common Frac Oils 1.0 7.0 (less than1.0)

200

Gasoline 1.3 8.0 3.2

NOTE: To caution about methanol vapours affecting sensors. Please refer to

your MSDS for all chemicals

A flammable gas is considered to be a gas that will burn when there is a

concentration of oxygen in the air. Flammable mixtures cannot be ignited and

continue to maintain a flame, unless the concentration of fuel is greater than the

LEL and lower than the UEL.

A methane/air mixture must contain more than 5% methane by volume for the

mixture to burn. If the mixture contains more than 15% methane by volume, it is

considered to be too rich and will not burn. The concentration must be within the

flammable range to ignite or sustain a fire.

Oxygen

The normal concentration of oxygen in ambient air is 20.9%. Abnormal

circumstances can cause this level to be increased or decreased. Oxygen

deficiency refers to abnormally low oxygen levels that can be serious and is often


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an undetected risk to human life. Reduction of oxygen levels is usually caused by

the consumption of oxygen by some chemical reaction or combustion within a

confined area or by displacement by other gases.

Oxygen enrichment refers to abnormally high concentrations of oxygen that can

be dangerous because of its tendency to increase the flammability and

explosiveness of materials and fuels. The leaking of compressed oxygen

containers in confined areas usually causes enrichment.

For safe entry, oxygen levels must be between 19.5% and 23.0%.

Flam m able and Exp los ive Gases

Explosions occur when a flammable mixture of gas comes into contact with a heat

source that exceeds the ignition temperature of the gas mixture. Not allconcentrations of flammable gases will explode. The Lower Explosive Limit (LEL)

determines the minimum concentration of the flammable gas in air that will burn.

Concentrations below the LEL and above the Upper Explosive Limit (UEL) will not

burn. Unfortunately, gas/air mixtures are seldom uniform so it is likely that if any

amount of combustible gas is detected then at some point in the system or

container, the concentration may be explosive. Flammable liquids normally have a

low flash point. This refers to the temperature at which the liquid releases vapours

at a rate sufficient to form an explosive mixture with air. Liquids with flash points

below ambient temperature will immediately release dangerous concentrations of

gas. Liquid leaks can be as hazardous as gas leaks.

Vapou r Dens i t y

When monitoring for the presence of gases or vapours, it is important to

understand vapour density, which provides valuable clues as to where to locate

gas sensors. Density is a characteristic of materials and is similar to weight. For

gases and vapours, air is considered to be the standard reference and its density

is set at 1.0. Gases and vapours lighter than air have densities less than 1.0 while

those heavier than air have densities greater than 1.0.

Assuming that air currents are negligible, it can be said that gases and vapours

with densities less than 1.0, such as methane, will tend to rise from the point of

escape and subsequently disperse into the atmosphere or accumulate in spaces

under roof structures of buildings.

Heavier-than-air gases such as propane and H2S tend to fall from the point of

escape, perhaps to floor level where some mixing with air occurs thus creating

pockets of mixtures, some explosive, others not. If there are sub-floor spaces

such as drain channels, pipe and cableways, and storage pits, then these heavier


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than air gases tend to accumulate there. A suitable source of ignition in such

areas will surely result in explosion and fire. Refer toFlammable limits for some

common flammable gases and vapourstable above.

I g n i t i o n Te m p e r a t u r e

Ignition temperature is the temperature that will cause a combustible mixture of

gas vapour to explode or burst into flame. Various fuels mixed in a variety of

concentrations can be explosive when ignited by the presence of a spark, flame or

hot surface that exceeds the ignition temperature. Variables such as

concentrations, pressure, and temperature all have an effect on ignition

temperature.

Pyr opho r i c I r on Su lph ides

Pyrophoric Iron Sulphides are created when rust and H2S combine in an oxygen

free environment

Pyrophoric meaning they can spontaneously ignite when exposed to oxygen.

They are created in oxygen free environments such as piping systems, reservoirs,

wellbore, and vessels where H2S has been present without oxygen.

Essentially rust (or Iron Oxide) is converted in Iron Sulphide, when these Iron

Sulphides are exposed to oxygen; an oxidation process begins that eventually

turns the iron sulphides back into iron oxide form.

This process creates an enormous amount of heat causing (in some cases) the

iron particles to illuminate and possibly glow. This is when nearby fuel sources

such as propane from a purge or other hydrocarbons can be ignited.

There is no set H2S content at which Pyrophoric Iron Sulphides will form or be

present, however there are some heavily researched indicators to the presence of

Iron Sulphides. They include

Scaling

Asphaltines

Sludge

Rust

Solids


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The age of a sour well, and long periods of time with equipment on sour

operations such as multizone sour completions can also be factors in determining

whether or not Iron Sulphides may be present

With an auto ignition temperature below that of room temperature, they pose a

definite hazard.

IRP A hazard assessment should be completed on iron sulphides for sour

locations. The operating companys site representative must be present.

The above mentioned indicators should be addressed if applicable.

Previous well analysis information if applicable, or operating company

technical/physical judgment of possible Iron Sulphides should be

addressed.These hazard assessments may be able to identify a

operating company or your companys Pyrophoric Iron Sulphide

procedures and safety guidelines. Local or federal legislation may alsobe valid.

Locat ion of Gas Sensors

Location of the gas sensor is very important. In general, lighter than air gases

requires the sensor to be positioned near the ceiling and heavier than air gases

require sensors positioned at low levels or in pits or trenches. Some things to

consider include:

Hydrogen sulphide mixed with methane in a process stream may follow

the same migration patterns as methane during a gas leak

Temperature, humidity, and air ventilation patterns

Mounting detectors close to the entrance of buildings, on the outside

wall.

Gas Detec to rs Measur ing Percen t LEL

Some gas detectors have two scales; the 100% scale measuring the % of a

flammable gas in a mixture, and the 4% scale for measuring the % of the LEL

Assume that the meter has been designed to measure hydrogen in a mixture. The

LEL of hydrogen is 4%. If a reading taken on the 100% scale indicates 10%, thenthe mixture is 10% hydrogen and is above the LEL of hydrogen. If a reading on

the 4% range indicates 10%, then the mixture contains 10% of the hydrogen

necessary to produce a flammable mixture. The mixture actually contains 4% x

0.1 = 0.4% hydrogen by volume.

The equipment operator must understand the difference between measuring the

% LEL and the % of flammable gas.


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Always consult the manufacturers operating instructions and procedures prior to

interpreting the results.

Caut ion:

No person shall remain in or enter into an area containing more than

20% LEL, unless it is for an emergency or rescue situation by trained

and competent individual(s)

When testing gas for LEL remember that the H2S concentration is

important relative to the safety of the worker conducting the LEL test.

The LEL of hydrogen sulphide is 4% gas by volume, which equates to

40,000 parts per million H2S.

Anytime the H2S exceeds 10 ppm special safety precautions must beimplemented.

At 40,000 ppm H2S, a worker would be immediately overcome while

testing for LEL.

These devices must not be used for continuous monitoring or for testing

H2S concentration in the gas

Pr epa r ing t he Me t e r

Be sure to follow the directions supplied by the manufacturer of your

gas detector.

Testing the atmospheres for the safety of workers requires that the gas

detection equipment be in perfect condition, properly calibrated, and will

be operated by trained and competent people.

Some portable equipment is designed to test for a combination of any of

the following: oxygen, hydrogen sulphide, carbon dioxide, and

flammable levels.

NOTE: Refer to CAPPFlammable Environments GuidelineandIRP 18 - Fire and

Explosion Hazard Management

4 .0 .13 .10 Moni to r ing fo r Exp los ive Mix tu r esIRP Monitoring for explosive mixtures with a suitable calibrated monitoring

device in the vicinity of potential ignition sources (e.g., pump) during

pumping/flowback operations is recommended. The monitoring device

must be calibrated using an appropriate calibration gas. The operations
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October 2009 xxxiii

must be suspended or an alternate method of flowback initiated to

eliminate an explosion risk around potential ignition sources.

IRP Wind direction devices must be strategically located around the lease.

NOTE: Monitoring for explosive mixtures with a suitable device is the only

practical method of determining safe operating conditions. Judging

conditions based on sight, smell, wind directions, etc., may be very

deceiving in that explosive mixture levels can change rapidly during a

flow back situation. Portable monitoring devices are available that give

direct readout of combustible gas explosive limits. A fixed sensor could

be located in an enclosed area such as rig pump house, separator

building etc.

4 .0 .13 .11 Cal ib ra t ion o f Exp los ive Mix t u r e Mon i to rsIRP Explosive mixture monitors must be calibrated regularly by a qualified

individual (seeIRP 18). Monitoring devices must be calibrated using an

appropriate calibration gas. Defective devices must be replaced or

serviced prior to commencing a flow back operation where monitoring

for explosive mixture will be required. The owners representative must

be aware of the limitations of the monitor for the gases and fluids

expected.

NOTE: As with any safety device, the degree of dependability of a gas detector

is directly proportional to the care it receives. All explosive mixture

monitors require routine maintenance on a regular basis, which includes

cleaning the device and its sampling system, checking voltage supply to

the unit and performing regular calibrations. Some of this servicing may

require the services of a qualified technician.

4 .0 .13 .12 Hydr a tes : Aw areness and Hand l ingGas hydrates are crystalline compounds formed, by the chemical combination of

natural gas and water, under pressure at temperatures considerably above the

freezing point of water. In the presence of free water, hydrates will form when the

temperature of the gas is below a certain temperature, called the hydrate

temperature. Hydrate formation is often confused with condensation and the

difference between the two must be clearly understood. Condensation of water

from natural gas under pressure occurs when the temperature is at or below the

dew point at that pressure. Hence, the hydrate temperature would be below and

perhaps the same as, but never above the dew point temperature. (Dew point is

the state of a system characterized by the coexistence of a vapour phase with an
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infinitesimal quantity of liquid phase in equilibrium. Dew point pressure is the fluid

pressure in a system at its dew point.)

While conducting tests, it becomes necessary to define, and thereby avoid,

conditions that promote the formation of hydrates. This is essential to the proper

field conduct of tests since hydrates may choke the flow string, surface lines, and

the well testing equipment. Hydrate formation in the flow string would result in a

lower value for measured wellhead pressures. In a flowrate-measuring device,

hydrate formation could result in a lower or higher gas flow rate. Excessive

hydrate formation may also completely block flowlines and surface equipment.

I n s u m m a r y , c on d i t i o n s p r om o t i n g h y d r a t e f o r m a t i o n a r e :

Primary conditions:

Gas must be at or below its water dew point with free water present

Low temperature

High pressure

Secondary conditions:

High velocities

Pressure pulsations

Any type of agitation

Presence of H2S and C02

Introduction of a small hydrate crystal

High specific gas gravity

For the purpose of well testing it is convenient to divide hydrate formation into

two categories:

1) Hydrate formation due to decrease in temperature, with no sudden drop in

pressure, such as in flow string or surface lines.

2) Hydrate formation where a sudden expansion occurs and/or pressure drops

such as in flow provers, orifices, backpressure regulators, and chokes.

If ambient temperature is low enough, ice build up may occur on the inside of pipe

when left idle, after flowing, due to condensation residue left on the inside walls of

piping systems. This is not a hydrate although it could lead to the formation of a

hydrate by the introduction of a hydrate crystal to the flow stream.


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IRP For the awareness and prevention of hydrates:

Programs supplied by the well owner should identify potential hydrate

problems by way of bottomhole temperatures, presence of free water,H2S and CO2 content, gas gravity, and downhole restrictions

Pre job safety meetings should reference the possibility of hydrates

Incorporate the primary and secondary conditions listed above

Provision for the injection of methanol should be planned prior to

flowing of the well

Consideration should be given to batching or injecting methanol down

the tubing and/or the annulus, if applicable, prior to flowing

Methanol should be batched or injected into the wellhead flowline before

opening the well to flow and during any future shutdown periods so as

to prevent ice build up on the inside walls of piping systems

Flowlines should be purged with a gas medium (propane/N2), where

available and when extended shut down periods are anticipated,

especially during cold weather operations

The introduction of surface heating facilities, such as line heaters, will

assist in the prevention of hydrates in surface equipment

Staging pressure drops will assist in the prevention of hydrates in

surface equipment.

Hydrate charts/tables must be available on the well site. The well test

supervisor must be trained and competent on the use of these charts

and tables.

IRP Where hydrate formation or ice build up is suspected in surface flow

lines, the lines must be proven to be clear by purging with methanol or

a warm gas or fluid before the lines are broken apart.

IRP During the pressure testing procedure and start up, all non-essential

workers must vacate the surrounding area of the testing equipment,flow lines, and wellhead.

SeeA p p en d i x V I I for hydrate graphs

Caut ion: Hydrates travelling through pipes have a high potential for plugging,

overpressuring, or rupturing lines.

NOTE: Sour gas more readily forms a hydrate than sweet gas


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4 .0 .13 .13 Work e r Sa fet y

IRP Before commencing any operation a pre-job safety meeting must beheld and hazard assessment performed and communicated. Suggested

topics are:

Scope of work

Procedures to be followed

Pertinent well and fluid characteristics

Responsibilities of each person involved in the operation

Emergency procedures, special hazards, and safe briefing areas

NOTE: Equipment must be routinely serviced and tested by qualified/competent

workers as per the manufacturer's specifications or regulatory

requirements. The owners representative is responsible to ensure an

onsite pre-job safety equipment inspection is completed (seeAppendix

V Production Testing Services Inspection Checklist).

IRP All applicable federal and provincial regulations must be adhered to,

such as TDG, WHMIS and Occupational Health and Safety, and WCB.

4 .0 .13 .14 Min imum Work e r Wear Requ i remen tsIRP A written protective clothing policy must be available onsite. The

following minimum work wear requirements must be followed:

A hardhat must be worn in the work area

Safety (steel toed) footwear must be worn in the work area

Safety goggles, safety glasses or safety prescription glasses with side

shields must be worn

Where hazardous chemicals exists, consult MSDS

Hearing protection where over exposure to noise may occur

Gloves must be worn as required, (e.g., specialty gloves for chemicals,

leather gloves for handling pipe, etc)

Un-torn, fitted clothing must be worn in the work area

Outer or covering apparel must be fire retardant where the potential for

fires exists


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Natural fibres for innerwear is preferred over synthetic fibres as

synthetic fibres do not provide adequate protection from heat related

exposure and they contribute to static electricity generation

All clothing that becomes contaminated with hazardous chemicals or

flammable fluids must be removed and replaced

Minimum safe standards for hard hats, footwear, eye wear, and ear

protection should be determined by the well testing company. The

following standards are appropriate:

Hardhats: CSA Z94.1

Footwear: CSA Z195 Grade 1

Eyewear, Goggles: CSA Z94.3

Hearing Protection: CSA Z94.2

4 .0 .13 .15 Min im um Genera l Sa fe ty S tandardsIRP The following minimum standards must be followed:

No smoking within 50 m of potentially flammable vapours

Facial hair must not impede the sealing of respiratory equipment

Intoxicating substances and intoxicated persons are not allowed on

location

General fatigue management

Firearms are not allowed on location except for emergency ignition of

uncontrolled gases.

An adequate supply of potable water must be on location (i.e., for

drinking, and emergency washing)

Good housekeeping practice is required for all of the location

The requirements of Workplace Hazardous Material Information Systemand TDG must be followed

A form of wind direction indicators must be present on location (e.g.,

windsocks, flagging tape, etc.)

An operational field phone must be present on location

A list of emergency contacts must be conspicuously posted on location


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A means of transport for injured persons must be on location in

accordance with local jurisdictions

An unobstructed exit path must be available

The safety standby method must be employed for all hazardous work

A properly calibrated gas detection apparatus must be on location.

Personnel must be properly trained in the use of this apparatus

H2S determinations must be performed while wearing breathing

apparatus. A minimum of two positive pressure type apparatus must be

at location and maintained in accordance with the manufacturer's

specifications and regulatory requirements

On sour well sites where the H2S concentration is greater than 10 ppm,the owner must provideSABAs in addition toSCBA.

When a significant volume of wellhead gas is produced, either to an

orifice device, or through a separator, notification should be given as

required by the local provincial authority.

Se e Section 4.0.13.18 Gas Flares

First Aid equipment and/or attendants must be supplied as specified by

the provincial OH&S authority

Appropriate fire fighting equipment must be available as determined by

the Hazard Assessment, Fire and Explosion Control Plan, and applicable

regulations.

Cold separator or pressure tank rig-up: Minimum 2 Class ABC, 9 kg

Heated Unit and flare stack or line heater, pressure tank and flare stack:

Minimum 3 Class ABC, 9 kg

Heated unit or line heater/pressure tank combination with second stage

separation or more than one item of auxiliary flow equipment: Minimum

4 Class ABC, 9 kg

Wellsite illumination must be sufficient to safely perform the job (RefertoIRP 23 Lease Lighting Standardscurrently under construction)

Safety stairs (or equivalent devices that would allow a rescue at the top

of a tank other than by ladder access) are required whenever breathing

apparatus is required at the top of a tank

Fall arrest equipment and a fall protection plan must be available as

required by OH&S regulations

IRP 4 2009 Well Testing and Fluid Handling

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