Flash liberation samples to match field conditions for accuracy

Posted by Matthew Loveley, PhD. on Jul 5, 2018 2:45:00 PM

Sometimes I’m asked why it’s necessary to perform a flash liberation test in the lab, when it’s so much easier and faster to use a computer model to measure flash gas.

My answer is twofold: First, it only takes 15-45 minutes in the lab, so you can still get results back the same day in most cases.Exact Flash Liberation

Second, we’ve seen that flash liberation testing can be much more accurate than computer models. The main issue with computer models is that, while they do an amazing number of calculations, those calculations are fixed and make many assumptions. They assume a “perfect world,” on every well, with few unaccounted-for variations in conditions, down-hole or on the surface.

Have you noticed that we really don’t encounter this perfect world in the oil patch? I bet you have. No two wells are the same, and most individual wells’ composition changes over time. Only an actual lab test can tell you what’s there— and even the lab test must be carried out under exacting conditions, which closely match the conditions at the wellhead.

Realizing that content information influences things like payments from midstream companies, emissions status for regulatory agencies and, very importantly, safety concerns—isn’t it important to make sure this information is as accurate as possible?

Flash liberation testing includes multiple tests under one “BIG” test.

What is included is a C11+ BTEX (Benzene, Toluene, Ethylbenzene and Xylene gas analysis of the “flashed” gas, GOR (gas to oil ratio), oil shrinkage, RVP (Reid Vapor Pressure) of the flashed “dead” oil, specific gravity/API and basic sediment and water (BS&W). This tells the buyer exactly what they’re getting and how to pay the producer for it accordingly.

Exact Flash Liberation

Here is the list of what we test for:

  • Gas Oil Ratio
  • Gas Specific Gravity
  • Dry & Ideal BTUs
  • Separator Volume Factor
  • Shrinkage Recovery Factor
  • Stock Tank Oil API Gravity
  • Stock Tank Reid Vapor Pressure
  • C11+ Gas Analysis
  • Gas Water Ratio (Water)

Flash liberation can also help make better field processing decisions.

Let’s say you’ve been flaring gas from a new well because the well is fairly distant from a gas gathering line, or processing plant. You thought it was more economical to just flare it than to spend money connecting the infrastructure because that’s what the computer model said.

But with the actual flash liberation test you discover that there’s enough salable content—propane, ethane, etc.—that you could recoup pipeline construction costs in a reasonable time frame. Now you can make that well even more profitable.

Yet another reason for testing is to get a handle on storage shrink. Shrink, or evaporation in tank storage, has less to do with detailed content and more to do with volume. Producers are sometimes surprised when they find that their calculated shrink is one thing and their actual shrink is quite different—significantly changing the amount of liquid actually sold.

In truth, occasionally the calculated loss is spot on, but other times it varies significantly. The only way to always know for sure is to have us do the test. Why deal with unknowns when you have a physical sample to work with?

And while I’m not at liberty to tell you all the steps we take, we make sure we care for every sample like it’s worth its weight in gold—or black gold, as it may be—because it really is.

Let us show you how we can get you accurate, actionable information, every time.

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Topics: Labs, Sample Testing, Flash Liberation