Sampling Best Practices

Whether you’re sampling source waters for completion operations, emulsion pads within a separator, coupons or pig returns, there are some basic steps for obtaining samples that will help with microbial testing.


When collecting samples from any system or process, refer to your company’s standard operating procedures to ensure it is done in a safe manner that is compliant with the site you are working on. This includes reporting to site supervisors, wearing appropriate PPE and site training. Some hazards to be aware of when sampling are:

  • Pressurized vessels and lines
  • H2S
  • Chemical hazards
  • Noise from surrounding equipment
  • Height hazards (fall arrest)
  • River current


  • Sample containers: minimum capacity of 100 ml (liquids) or 5 g (solids)
  • Labels (OSP can provide Sample Labels)
  • Sharpie
  • Electrical tape
  • Cooler / Ice pack
  • Ziploc bags (for ATP filters)

Liquid Sample

  • Follow safe work procedures when sampling liquids
  • Mix/roll fluid tanks if possible (to homogenize fluid)
  • Run 3-5 L of fluid through sample valve (to flush valve)
  • Rinse the sample container with sample fluid and empty container
  • Fill sample container to limit oxygen head space (minimum 100 ml)
  • Cap sample container tightly and seal with electrical tape
  • Take fluid samples from other points in tanks or vessels, fluids sources, etc

Solid Sample

  • Follow safe work procedures when sampling solids. Handle as little as possible.
  • Obtain a representative sample by sub-sampling from various points in the solids source (i.e. cone and quarter method, etc.)
  • Place a minimum of 5 g of sample in a suitable container (The size of a quarter)
  • Cap sample container tightly and seal with electrical tape

When you are sampling, reach out to OSP for support and direction.