Soil Gas Sampling with a Helium Leak Detection Shroud Bruce Godfrey - - PowerPoint PPT Presentation

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soil gas sampling with a helium leak detection shroud
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Soil Gas Sampling with a Helium Leak Detection Shroud Bruce Godfrey - - PowerPoint PPT Presentation

Mar 25, 2024 396 likes •571 views

Soil Gas Sampling with a Helium Leak Detection Shroud Bruce Godfrey & Stefan DAngona Introduction a. Leak Detection Options b. Helium Leak Detection c. Leak Tracer System Design d. Use and experience Why Leak Check? Proof of Sample

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SLIDE 1

Soil Gas Sampling with a Helium Leak Detection Shroud

Bruce Godfrey & Stefan D’Angona

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SLIDE 2

Introduction

  • a. Leak Detection Options
  • b. Helium Leak Detection
  • c. Leak Tracer System Design
  • d. Use and experience
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SLIDE 3

Why Leak Check?

Proof of Sample Integrity Leaks result in sample dilution

  • Leaks in Train Fittings
  • Down Well Leaks
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SLIDE 4

Leak Testing Options

  • Liquid Tracer
  • 2-Propanol (IPA)
  • Qualitative, interferes, raises RL’s
  • Helium
  • Quantitative, no interference
  • “Pain in the neck”
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SLIDE 5

Helium Advantages

  • Frequently used for leak detection
  • Inert, doesn’t interfere with

targets

  • Easily Measurable
  • Allows estimate of dilution
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SLIDE 6

Why Build & Rent He Shrouds?

  • Our clients asked us
  • Design using best available

technology

  • Lab resources required
  • cleaning, maintenance, testing, validation
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SLIDE 7

Design Considerations

  • Guidance compliant
  • Small: Packaging & Transport
  • Minimize field tubing connections
  • Real Time leak detection before sampling
  • Scalable: 12 wells/8 hours
  • Low Cost & Simple to Use
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SLIDE 8

Shroud Components

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SLIDE 9

Helium Detectors

  • Flow Through and Diffusion Cell
  • Diffusion Detector inside shroud
  • Flow Thru Detector in purge line
  • Small, lightweight, portable, simple
  • Battery Powered
  • Quick, Accurate, Precise
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SLIDE 10

Helium Detectors

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SLIDE 11

Costs

  • Shroud equipment rental adds $70 per

sample for 8 wells

  • $235 for the first sample
  • Additional field labor costs
  • What circumstances justify extra costs for

a QC procedure?

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SLIDE 12

Shroud/Train Prep

  • Disassemble Shroud/Train/Valve
  • Clean train with Air/N flow, 60C, 4-8 hrs
  • Blank test train with clean lab air, TO-15
  • Performance test with TO-15 cal gas mix
  • Reassemble Valve, Train, Box
  • Leak Test
  • He Charge & leak detector check fittings
  • Vacuum Decay “Shut in” Test
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SLIDE 13

Purge Test with In Line He Detector

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SLIDE 14

Dual Depth Sampling Shroud

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SLIDE 15

Duplicate Sampling Shroud

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SLIDE 16

Acknowledgements

  • Blair Okuma and crew @ C&T
  • Loi Chau/Alfonso Ang: MACTEC
  • Ross Tinline: SVC Environmental
  • Heather Wollenburg/Robin Mock: ERRG
  • Jeff Schmidt: IRIS Environmental
  • Mark Blaisdel: ITSI