Propane 101 -- July 12, 2015

A reader sent me this link for various reasons. It's a good read.

The best part of the article was the explanation by the president of this Canadian oil and gas company with regard to "shutting in" propane.

Unfortunately, the usual solution for low prices – shutting in production and reducing supply – isn’t so easy for propane. The decision is a bit more complex than that, and so some explanation is required.

Starting back in the reservoir, raw natural gas is typically at a temperature and pressure where propane molecules (C3H8) are in gaseous phase – as are the methane (C1H4), ethane (C2), butane (C4), and many of the heavier hydrocarbon chains (C5+).

As this raw gas is produced up the wellbore, the temperature and pressure drops and the heavier hydrocarbons condense into liquid form. What tends to arrive at the low pressure inlet of our gas plants, for example, is a mix of liquid condensates and pentanes, along with gaseous lighter hydrocarbons.

These gases still contain too much of the heavier hydrocarbons to safely consume in our homes, so Peyto has to process the gas (dry it and cool it) to remove the water vapour and condense even more of the heav ier hydrocarbons out of the gas.

Our sales products, at the out let of our facilities, ends up being stabilized condensates, a mixture of pressurized LPG (Liquid Petroleum Gases), and high pressure lean gas. The LPG is a mix of approximately 1/3 Pentane (C5+), 1/3 Butane (C 4) and 1/3 Propane (C3). This LPG mix is then transported to a refinery where it is “fractionated” or distilled into the pure components.

As you would expect, shutting in just the propane because its price is negative, isn’t possible. You’d have to shut in the entire gas stream. Alternatively, warming up your plant process to condense less propane into liquid form (thereby leaving it in the gas phase) also leaves some butane and pentane in gas phase and those products are still worth more as liquids than gases. Plus, at some point, the gas becomes too rich to make lean gas specifications. So the decision of what to do about negative propane prices, like we’ve had in April and May is a much more complex one.

Our solution at Peyto has been to extract all of the more valuable liquids (C4 & C5+) that we can and then try to “push” an optimal amount of the propane back into the gas stream so that we get paid in increased heat content in the gas rather than liquid barrels. This is often referred to as propane rejection.

In order to find that optimal amount, we have to consider all of the component prices and the liquid recoveries at various process conditions. We are looking for the most optimal combination of gas and liquid recoveries which yields the greatest possible revenues.

This optimal combination won’t necessarily yield the greatest combined production volume. But maximum production is not the point, maximum revenue is. As I’ve said before, this is one of the reasons why owning and operating your own processing facilities is so important.