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LSA/NORM

Training and Awareness Pack

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Why Oilfield Scale Occurs • Reservoir water is rich in calcium, barium

and strontium ions. Injection water is rich in sulphate ions. When they mix, precipitation of calcium, barium and strontium sulphate occurs.

• Pressure and temperature drops also promote precipitation.

• This causes a layer of scale to form inside production tubing and process vessels.

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Why it Becomes LSA • Reservoir rock contains small amounts of

natural uranium and thorium and daughters. One daughter, radium, is water soluble - dissolves in the reservoir water.

• Radium precipitates with the barium and calcium ions to make the scale slightly radioactive.

• This makes the scale a Naturally Occurring Radioactive Material (NORM) which is of Low Specific Activity (LSA).

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Where it Appears • LSA scale appears within the well fluid

handling system -Tubing string (especially tailpipe)

Liner, below the packer

Subsurface Safety Valves

Wellheads

Manifolds

Separators

Oil coolers

Produced water pipework

• It can also appear in the service water system, in pig wax, in storage cells etc.

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How it Gets There • Incompatible waters mix as they pass through

perforations - this starts scale depositing in the tailpipe and tubing, then throughout the plant.

• Deposition is heaviest in areas of turbulence - bends, valves, restrictions.

• Also where temperature or pressure changes occur - chokes, separators, coolers.

• Separator deposits - clays may absorb radionuclides directly from water.

• Service water systems probably due to concentrating

natural radioactivity from seawater.

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How it Looks • Pure barium sulphate is hard dense white solid.

Pure LSA scale can be like that (especially in tubulars).

• More usually thin, eggshell-like, light or dark brown.• Can be stratified, like rings in a tree trunk.• Sometimes deep in the surface matrix, so not visible.• Separator sludges are granular suspensions.• Pig waxes are black tarry materials, often with

chunks of rust and scale mixed in.

• See Photo.

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An LSA Contaminated Tubular

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Structure of the Atom • All matter consists of atoms.• The atom consists of a nucleus, made up

of protons and neutrons, and a cloud of electrons surrounding the nucleus.

• Each sub-atomic particle has its own properties in terms of mass and charge- Proton Mass = 1 Charge = +1

Neutron Mass = 1 Charge = 0

Electron Mass = 0.0005 Charge = -1

• See picture

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Atomic Structure

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Types of Radiation

• Some atomic structures are unstable because the ratio of protons to neutrons in the nucleus is wrong.

• These naturally decay to a stable configuration by emitting radiation.

• Three types of radiation are emitted - Alpha 2p+2n Mass = 4 Charge = +2

Beta electron Mass = 0.0005 Charge = -1

Gamma photon Mass = 0 Charge = 0

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Hazards of Each Type • Alphas - large and highly charged. Easily

stopped and absorbed. Sheet of tissue, outer skin or centimetres of air will stop them.

• Betas - smaller and less charged, so more penetrating. Sheet of cardboard, metal foil or metres of air will stop them.

• Gammas - pure electromagnetic energy. Very penetrating. Require lead sheet, steel plate or many metres of air to stop them.

• See penetration picture.

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Penetration of Each Radiation Type

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External and Internal Hazard • These properties determine effect on health.• Gammas can penetrate body from outside

and damage deep internal cells. This penetration makes them an External Hazard.

• Alphas/betas cannot penetrate far from outside. However if alpha emitting materials enter the body, particularly the lungs, the size and charge of the alphas makes them very damaging to the cells they hit. This alpha toxicity makes them an Internal Hazard.

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Uranium -238 and Thorium-232 Decay Series • Two decay series in LSA scale - U-238 and Th-232.• Uranium-238 emits alphas, betas and gammas to

decay through protoactinium, thorium, radium, radon, polonium and bismuth to stable lead-206.

• Thorium-232 emits alphas, betas and gammas to decay through radium, actinium, radon, bismuth, polonium and thallium to stable lead-208.

• Each decay step takes an approximate length of time (half life). Because some half lives are long, ratio alphas/betas/gammas is fairly constant.

• See decay series charts.

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Uranium -238 Decay Series

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Thorium -232 Decay Series

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Hazards of LSA Scale • Because LSA scale contains so little activity,

the external field is generally low. However some old tubulars, separators, Wemcos may give measurable fields.

• Because of the high alpha content, LSA scale is a significant internal hazard.

• Therefore priority is to stop LSA scale particles being inhaled or ingested.

• This alpha toxicity also makes safe disposal important.

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Units of Radiation • Unit of Activity - Becquerel (Bq)

1 Becquerel = 1 disintegration per second

This is effectively the size of the source, or as Bq/g, the amount of radioactivity in a substance

• Unit of Absorbed Dose - Gray (Gy)1 Gray = 1 joule per kilo absorbed

This is the amount of radiation energy absorbed

• Unit of Corrected Absorbed Dose - Sievert (Sv)1 Sievert = 1 Gray x Quality Factor

This is the “harmfulness” of absorbed radiation

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Legislative Overview • Two main pieces of legislation.• Ionising Radiations Regulations - set

standards for protection of workers, by requiring certain precautions.

• Radioactive Substances Act - set standards for protection of public and the environment, by setting conditions for holding, using, storage and disposal.

• Transport regulations are separate.

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Ionising Radiations Regulations • Set standards for protection of workers

Risk Assessment

Appointment of Radiation Protection Adviser (RPA) and Radiation Protection Supervisor (RPS)

Local Rules

Controlled and Supervised Areas

Dose control

Training and awareness

• Regulated by HSE.

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Radioactive Substances Act • Set standards for protection of public and

environmentRegistrations and Authorisations set detailed conditions

Contaminated equipment to specified locations

Offshore waste to sea only

Ground to below 1mm

Annual total discharge activity limit

Record of all discharges

No transfer between platforms

• Regulated by SEPA.

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Definition of “Radioactive” • IRR brings a substance into its remit at 100

Bq/g.• RSA has a Schedule by radioelement - for

radium the level is 0.37 Bq/g.• The large difference is due to the intent of the

legislation - protection of the public and bioaccumulation require lower limits.

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Rare Earths Exemption Order • RSA is supported by Exemption Orders -

allow some exemptions for certain radioelements under certain conditions.

• Phosphatic Substances (Rare Earths) EO can be used for LSA scale.

• Exempts material up to 14.8 Bq/g from RSA.• User must be able to prove EO applies.

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Radiation Protection Adviser • Every radiation employer must appoint a

Radiation Protection Adviser (RPA)Professional radiation specialist

Must be accredited by professional body

Registered with HSE

Must be consulted on radiation protection matters

Carries out annual inspection of each location

Shell RPA - Dr. Brian Heaton

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Radiation Protection Supervisor • At workplace level, every radiation employer

must appoint Radiation Protection Supervisor(s) (RPS)Supervise radiation work directly

Ensure Local Rules are met on the worksite

Shell Expro 2 day course - Level 3

Train meter users and workforce - Level 2M, 2, 1

Appointed in writing - in APR and Local Rules

Shell Competent Person is lead RPS

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Local Rules • Every radiation employer must make Local

RulesDetailed and prescriptive rules

Tailored to each location

Written in cooperation with Business Units and RPSs

Checked and approved by RPA

In Document 3133-001

Also contains Source Register and LSA Record of Work

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Shell Expro LSA Local Rules • In Document 3139-001

01 - Preparation and Interfacing Prior to Work08 - Working on LSA Contaminated Equipment09 - Decontamination on the Installation10 - Milling on LSA Scale11 - Handling of LSA Contaminated Tubulars12 - Handling of LSA Contaminated Well Control Equipment13 - Handling of LSA Contaminated Pigs and Pig Debris14 - Entry and Cleaning of LSA Contaminated Vessels15 - Discharge of LSA Scale to Sea16 - Dispatch of LSA Contaminated Items Onshore17 - Instruction to Refurbishment Contractors18 - Record Keeping, Reporting and Auditing19 - Radiation Training and Competence

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Controlled and Supervised Areas • Every radiation employer must set up

Controlled and Supervised Areas.• Controlled Area

Where it is necessary to restrict significant exposure

Where dose likely to exceed 6 millisievert/y

• Supervised AreaWhere risk needs to be kept under review, or

Where dose likely to exceed 1 millisievert/y

• Shell Expro sets up an LSA Supervised Area around LSA work.

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Dose Controls • Every radiation employer must limit radiation

exposure ALARPEngineering controls

Systems of Work

Personal protective equipment

• Dose limitsWorkers - 20 millisievert/y

Public/others - 1 millisievert/y

At 6 millisievert/y, workers must be Classified.

• Not really relevant to LSA scale work (external radiation limitation).

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Philosophy of LSA Management • Stop inhalation or ingestion of scale particles-

Stop dust being created

Stop dust becoming airborne

Stop dust from entering the body

Contain scale in one area and minimise contact

• To achieve this we -Adhere to Local Rules

Keep scale wet to stop dust rising

Wear personal protective equipment

Set up LSA Supervised Area and restrict contact

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LSA Workflow

• General workflow is as follows -Identification of work with LSA potential

Preparation for work with LSA potential

Detection and identification of LSA contamination

Working on LSA contaminated equipment

LSA disposal to sea

LSA contaminated equipment to onshore cleaner

• The rest of this pack will cover each of these areas in detail.

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Identification of Work with LSA Potential

• Assume all fluid bearing systems are LSA contaminated until proven clean.

• Use Local Maps to identify areas of known LSA contamination.

• External monitoring may identify very active LSA but not reliable.

• Test all systems at first breach, and regularly as new surfaces are encountered.

• Record zero readings.

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Preparation for Work with LSA Potential

• Local Rule 01 (onshore), 08 (offshore).• Onshore planning of work - coordination

between Shell and contractor(s).• LSA Procedures/Local Rules in Workpacks.• All parties must know/understand Shell and

own Local Rules.• Equipment - muncher, tape, labels, tags,

polythene, PPE etc.• Training and awareness. Tool Box Talks etc.• Permit to Work.

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Detection and Measurement of LSA Scale - 1

• Shell standard LSA meter - Mini 900 with 44A probeScintillation counter - detects high energy betas and gammas

Readout in counts per second (cps)

Fairly robust probe

Not intrinsically safe

• See Picture.

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Mini 900 with 44A Probe

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Detection and Identification of LSA Scale - 2

• Special meter for confirming external contamination on tubulars - Mini 900 with EP15 probeGeiger tube - detects alphas and low energy betas

Readout in counts per second (cps)

Fragile probe

Not intrinsically safe

Used by some operators and contractors as their standard LSA meter - Shell prefers 44A probe

• See Picture.

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Mini 900 with EP15 Probe

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Detection and Identification of LSA Scale - 3

• Dosemeter - ICI Gammatrol PRI 90 and 90sMeasures external radiation field at a point

PRI 90 readout is in millirads per hour (mrad/h)

Converts to microsieverts per hour (μSv/h) by multiplying by 10 (1 mrad = 10 μSv)

PRI 90s readout is in microsieverts per hour (μSv/h)

Both have three ranges - 100, 1000, 10000 μSv/h

Use 100 μSv/h range for LSA scale fields

Intrinsically safe

• See Picture.

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ICI Gammatrol PRI 90

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Selection and Use of Meters

• The Mini 900 with 44A probe is Shell’s standard meter for LSA identification.Measuring gammas is more reliable than alphas/betas in the field situation, as they are not attenuated by water, mud, wax etc.

• The Mini 900 with EP15 probe can be used to confirm external contamination on tubing.

• However the Mini 900 with EP15 probe is not always reliable for LSA identification in the field situation.

Alphas/betas may be attenuated in dirty material

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Meter Reading to Declare LSA

• Using the Mini 900 with 44A probe, a reading of 3 cps above background is LSA.3 cpsabg is the lowest statistically reliable reading with the meter

Does not convert directly to Bq/g, but 3 cpsabg is in the range of 0.37 Bq/g (depending on thickness etc)

Note - it is not possible to convert from cpsabg to Bq/g as you do not know the thickness and thus the mass of scale that the counts come from.

• We identify contamination, we do not measure scale activity.

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Use and Care of the Meter

• Local Rule 08.• Turn on, battery check (green), read.• With or without speaker.• Function test - use test source before use.• Probe and meter are matched - do not mix.• Remove cap, replace with thin plastic bag.• Take background, bring to surface, back away - look

for rise and fall.• Test all new exposed surfaces.• Calibrate annually - Aberdeen University.

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Work Precautions - LSA Contaminated Equipment

• Local Rule 08.• Record the whole job on Form F/4507 as you go.• Regular monitoring of surfaces.• LSA Supervised Area.• Personal protective equipment.• Personal hygiene - shower after work.• PA announcement before work.• Keep scale wet during work.• Minimise wire brushing, grinding, burning.• If Mini 900/44A >200 cps, check with Gammatrol PRI

90. If >7.5 μSv/h, contact BU HS&E team. • Label and tag everything.

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Work Precautions - LSA Supervised Area

• Local Rule 08.• Barriered off and labelled as “LSA Supervised Area”.• Deck lined with polythene to collect any loose scale.• Entry controlled and logged.• PPE donned on entry, removed at exit.• Contamination check on exit.• Minimise entry - need only.• Eyewashes and showers where appropriate.• PA announcement on setup.• All LSA to be contained in the area.• When work completed, area thoroughly cleaned and

monitored.

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Work Precautions - Personal Protective Equipment

• Local Rule 08.• One piece slicker suit or Tyvek disposable suit.• Impermeable gloves.• Impermeable boots.• Facepiece respirator to EN146FFP3 - 3M 8835 or

Moldex 3405.• Eye protection - safety goggles.• All PPE to be cleaned after job and monitored as

free from contamination. Must be reused or returned as normal waste.

• Contaminated PPE cannot be sent to shore.

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Work Precautions - Personal Hygiene

• Local Rule 08.• No eating, drinking, chewing gum, sweets, tobacco.• No application of barrier cream.• All cuts and abrasions effectively dressed.• Wash hands and face before eating, drinking or

smoking.• Shower after work.

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Work Precautions - Labelling and Tagging

• Local Rule 08.• Tape and tag immediately after testing.• Positive reading - yellow/black LSA Contaminated

tape + tag.• Negative reading - green LSA Externally Clear tape

+ tag.• Mark tags with cps, Date, Name of Tester, Platform.• Tubulars - tape ends + 2 tubular tags• See pictures.

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Labelling and Tagging - LSA Contaminated

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Labelling and Tagging - LSA Externally Clear

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Labelling and Tagging - Tubulars

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Work Precautions - Offshore Decontamination

• Local Rule 09.• Mainly for repair and reinstatement on installation.• Not for tubulars or very large items.• Carried out by experienced contractor cleaning crew.• Extensive decontamination requires dedicated

habitat - preferably purpose-fitted container.• Habitat is an LSA Supervised Area.• Can be used for onshore refurbishment or scrap -

Clearance Certificate required.• Arisings must be discharged as per Authorisation.• Work must be recorded on Form F/4507.

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Work Precautions - Milling of LSA Scale

• Local Rule 10.• LSA scale cleanouts in wells - usually coiled tubing.• Large LSA scale particles caught in junk-sub, small LSA

scale particles entrained in brine.• Solids in junk-sub must be disposed to sea as per

Authorisation. Sample and mass estimate required.• Light brine discharged to sea. Sample and mass estimate

of solids required.• Heavy brine filtered for reuse - precoat filter. Sample and

mass estimate of backwash solids required.• After work, mud handling equipment and filter equipment

must be decontaminated and tested.• Work must be recorded on Form F/4507.

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Work Precautions - LSA Contaminated Tubulars

• Local Rule 11.• Use Mini 900 with 44A probe. Lay down tubular,

insert probe into pin end.• Test every fifth joint until LSA indicated, then every

joint from then on.• Mark clean tested joints with green tape + tags.• Mark contaminated joints with yellow/black tape +

tags. Fit end caps, segregate. Mark slings with tape.• Tape and tag each joint - not bundle.• Test for external contamination - Mini 900 with EP15

probe, or wipe test if meter not available.• Work must be recorded on Form F/4507.

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Work Precautions - LSA Contaminated Pigs

• Local Rule 13.

• Only on installations which receive interfield pigs.

• Use Mini 900 with 44A probe. Pig and pig wax.

• LSA precautions apply for handling and cleaning.

• If pig is to be reused directly, visually clean and send back to launch installation.

• Wrap pig in polythene, tape, label as visually but not radiologically clean.

• Send sample(s) of pig wax to UESP to determine if Rare Earths exemption applies.

• If exemption applies, send wax onshore for disposal.

• Work must be recorded on Form F/4507.

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Work Precautions - LSA Contaminated Vessels

• Local Rule 14.

• Carried out by experienced contractor cleaning crew.

• Vessel entry precautions apply.

• External radiation check with PRI 90 dosemeter. If >7.5 microsievert/h - vessel is Controlled Area. Otherwise LSA Supervised Area.

• Prior to entry, flush vessel as much as possible.

• Arisings must be discharged as per Authorisation.

• Sampling and mass estimate very important as these discharges are usually large.

• Sampling is a Shell Expro responsibility.

• Work must be recorded on Form F/4507.

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Discharge of LSA Scale to Sea

• Local Rule 15.• Conditions set by Authorisation, must be strictly met.• All free scale, sludges must be discharged to sea.• Dedicated hose below sea surface.• Ground to below 1 mm (confirm).• Suspend diving.• Authorisations contain discharge limit - 3-10 GBq/y• Must sample discharges and estimate mass.

Samples sent to UESP for radiological analysis. Tracked in spreadsheet.

• Discharges must be recorded on Form F/4507.

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Sampling of LSA Discharges

• Local Rule 15 Appendix.• Sample grinder output to check particle size.• Sample discharge solids for radiological analysis.• Samples must be representative of total discharge.• Samples about 100 g (50 ml).• For discharges <100 kg, single sample sufficient.• For larger discharges, eg separators, several

samples probably required.• If scale differs markedly in places, sample each type.• Samples must be recorded on Form F/4507.

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Dispatch of LSA Contaminated Items Onshore

• Local Rule 16.• Must be properly sealed, labelled, taped, tagged.• Proper documentation - manifest “LSA

Contaminated”, Dangerous Goods Declaration. • Must go to AEAT Dounreay for decontamination.• LSA1 package, Group 2912.• Items must be recorded on Form F/4507.

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LSA Record Keeping

• Local Rule 18.• Complete LSA job recorded on Form F/4507.• Contains eight boxes -

A - LSA Job NumberB - Job DetailsC - Monitoring DetailsD - Sand/Scale Discharged to SeaE - LSA Scaled Equipment BackloadedF - Discharge AnalysisG - CommentsH - Supervised Area Log

• All boxes must be completed. Maximum information.• In addition to contractor records - Shell’s overview.

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LSA Record Keeping - Form F/4507 A-C

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LSA Record Keeping - Form F/4507 D-G

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Inspection and Audit

• Local Rule 18.• HSE and SEPA have the right to inspect any

authorised premises at any time.• To confirm terms of IRR, RSA, registrations and

authorisations are being met.• Sanctions include Warning Letter, Enforcement

Notice, Prosecution (fine, imprisonment).• SEPA will compare their application/records with

offshore work records to ensure consistency.• Shell Expro carries out annual audit of each platform

RPA audit of radiation protection arrangements

Record keeping audit

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Training and Awareness • Local Rule 19.• Shell Expro has produced a Competence Matrix

Five levels - 5 - Expert - RPA

4 - Senior Specialist

3 - Shell RPS

2 - Working with LSA hardware

(2M - LSA Meter user)

1 - General workforce

• Also approved training for each level.

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Summary

• LSA scale represents two types of risk to Shell Expro

A HS&E risk

A legal, reputation and business risk• Both are real and important risks and must be taken

seriously.• We have an LSA management system to protect us -

described in Local Rules

Understand it

Use it (precisely)

Record everything• Protect yourself, your colleagues and the Company.

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Keep Us Out of the Headlines!

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The Solid Gold Tubulars Return From Italy