Pre-Site Inspection – Flash Gas Emission Testing

Have you had your production tank batteries tested to make sure you are in compliance and up to date with the EPA’s Quad O regulations? If not, let OTA Compression help you out with testing. One method (the most accurate) that we utilize is called, “Direct Measurements.” The tank battery and auxiliaries (i.e. thief hatches, vent valves, etc.) must be in good working order or the test may be flawed, which is why we offer a pre-site inspection and highly recommend it. Let’s discuss.
Pre-site inspections are very important, especially if the tank battery is older and might not be in the best condition. Pre-site inspections are vital, in many cases. Equipment setup issues can take days to correct and if not caught before testing day it will cost the operator extra money for our testing technicians to remain on standby.
Questions to ask yourself when considering a pre-site inspection are:

  1. Are the vent lines of the produced water and crude oil tanks commingled?
    • If yes, then only one meter is needed for most applications
    • If not, are the vent lines from each set of tanks commingled?
      • If so, at least two meter runs will be needed.
      • If not, the operator should consider commingled vent lines to lower the testing cost (less labor) and the operator will want to commingle vent lines to channel ALL vapor to a control device or VRU.
  2. Are vent lines accessible?
    • If not, a man lift will need to be made available to change out weights
      1. A vent valve located above a fiber glass tank is NOT accessible without a man lift for safety reasons.

3. Are the thief hatches in good working order?

  • If not, OTA can place gaskets and springs before testing. If the hatch (or hatches) are beyond repair, this is something to be found during pre-site (it may give us false-negative flow rates because of a leak.

4. Are there access ports (2”, 3”, 4” NPT connections) in the vent lines?

  • This can be either on the tanks or further down the line toward the emission control device (ECD).

5. Is a VRU or Control Device in use?

  • If yes, the emission control unit will need to be shut down and isolated from tank emission flow.
  • Isolation valve to emission control unit available (or plug)?
    • If not, client needs to install one before testing can commence.

6. Are there any P-Traps?

  • If so, any and all liquid will need to be drained OR the meters will need to be set upstream of P-Trap.

7. Are any wells shut-in for time of testing?

  • If so, testing can still be conducted but the following information is required…
    • Productions rates: 24 hour testing period production rates (BOPD and BWPD) and average/highest production rates of down wells.

8. Is >10 PPM H2S in the flash gas stream present or anywhere field techs are potentially exposed?

  • If so, industry/OSHA requires two man crews for the job.
  • H2S sampling needs are:
    • Available port (i.e. ball valve tap) inro vent lines or directly into storage tanks (1/4” – 4” NPT connections)
      • All wells MUST be producing at time of sample extraction.

Pre-Site Inspection – Flash Gas Emissions Testing
So if you need to conduct Direct Measurements testing and you are unsure of the above requirements, let OTA do the work for you and do the pre-site inspection to ensure you are getting the most accurate report back. As always, do not hesitate to contact an OTA Representative in your area to help you