Times have changed for the humble upstream flare. Flares used to symbolize success—a visible mark of successful exploration. Today, they are (rightly so!) viewed as a sign of failure: they represent missed opportunities to conserve resources, contribute to unnecessary greenhouse gas emissions, and pose health risks to communities near upstream opportunities.

A hard ‘no’ on flaring from the EPA

Flaring is no longer acceptable. It also now is all but illegal in the US. In its new OOOOb regulation, the Environmental Protection Agency (EPA) has, among many other new rules, included a near ban on routine flaring (it is prohibited for newer facilities, while there are opportunities to receive exemptions for older facilities).

The focus of OOOOb is associated gas, which will no longer be permissible to flare routinely. Instead of flaring, the EPA requires operators to handle their associated gas in one of four ways:

• Sell it—a great option for sites with sufficient takeaway capacity
• Use it to generate power on location—a great option for sites that need considerable amounts of power
• Reinject it—a great option for sites with cooperative geology
• Use it for any “other useful purpose”

The first three options are familiar. Many operators already evaluate these options and routinely flare only if none of them are practical.

“Other useful purposes”—no mystery

But what’s behind the fourth option? It may look mysterious, but it actually covers options using a bunch of technologies that are being deployed more and more often. “Other useful purpose” refers to converting the associated gas to another commodity such as

• fuels, for example, compressed natural gas (CNG) or synthetic crude oil
• chemical feedstocks, for example, hydrogen or methanol
• raw material, for example, carbon fiber or fertilizer

The new regulation tells operators that they must use one of these options or technologies, but it doesn’t say which one. So, how is an operator supposed to decide which of the “Gas-to-Value” technologies is right for them? Or, if any of them are even possible?

Thermodynamics to the rescue!

The answer lies in thermodynamics. You didn’t see that one coming, did you! In fact, engineers here at SLB have been working with thermodynamics for some time. For example, the team built the thermodynamic calculation engine using Symmetry™ process simulation software, which is used to design and optimize processing plants and other facilities throughout the energy industry.

More recently, our engineers developed thermodynamic models of nearly every commercially available technology that converts associated gas for any “other useful purpose,” including technologies that transform gas to CNG, to hydrogen, to methanol, and more.

The thermodynamic models are useful because they can identify how efficient these technologies are, when applied at specific location. Their efficiency depends on the properties of the gas they’re being applied to, such as the flow rate, pressure, and composition.

Technoeconomic analysis—and how Chord Energy did it

A thermodynamic model can determine the efficiency for each technology when applied at a particular location. That result can be used as part of a technoeconomic analysis, where the efficiency of each technology is analyzed alongside its specific, local economics.

This includes analyzing the purchasing prices of any additional inputs that might be required, like electrical power or cooling water, and the selling prices of the final product, which is especially valuable for products like methanol where the price varies across locations.

The result of that analysis is an estimate of how much upfront investment is required and how much revenue will be generated for every gas conversion technology that might be used on a particular location.

As a real-life example, using thermodynamics for a technoeconomic analysis helped Chord Energy® to find the likely most profitable way to handle their associated rich gas from disconnected well sites in the Bakken: conversion to methanol. That conversion was both efficient, because the properties of the gas matched the conditions where methanol conversion is most effective, and economic, because methanol is in high demand in the Bakken and its price there is high.

The best? There’s no such thing

There are many vendors of “other useful purpose” technologies, and each one is happy to say that their method is THE BEST. But there’s no such thing. It always depends. That’s why our methane consulting team works with operators to figure out what’s best gas-to-value option for their individual site, by analyzing each technology the same way, using the same assumptions, performing rigorous thermodynamic analysis, and considering the unique technical and economic factors relevant to a particular location.

The team produces a report listing the profit and loss that can be expected from each technology, and operators can use that report to identify which vendor to pick. Crucially, only the technoeconomic analysis is provided, not any of the actual conversion hardware, which is a huge cost saving.

Knowing you’ve explored all options

Even though there are many gas conversion technologies available, sometimes none of them are realistic. For older facilities, the EPA allows this analysis—explaining why no alternatives are feasible—to be used as grounds for an exemption from the complete ban on routine flaring.

But in our experience, most of the time, at least one alternative is viable. By identifying the right technology, operators can typically stop routine flaring and make money by converting the gas.

In other words, in the majority of cases, thermodynamics can help operators not only comply with regulations but also reduce their greenhouse gas footprint and increase their revenue. All at the same time. So while everybody has learned to look at flares and see only failure, thermodynamics teaches us to see the opportunity in every flare—and how to go unlock it.