December 2021 /// Vol 242 No. 12)
Overcoming technical hurdles to eliminate routine flaring
Despite exacting a heavy environmental and financial toll, routine flaring remains a persistent practice in the oil and gas sector. The technical solutions for ending flaring are both practical and financial in nature. Three hurdles are commonly faced when implementing flare gas to power projects.
Despite exacting a heavy environmental and financial toll, routine flaring remains a persistent practice in the oil and gas sector. This gas could be captured and used for productive purposes, but a lot of it simply isn’t—while flaring levels are down 5% from 2019, as much as 142 Bcm are flared each year. This wasted gas is the equivalent of 5000 MW of power over ten years, enough to power millions of homes.
The technical solutions for ending flaring are both practical and financial in nature. Three hurdles are commonly faced when implementing flare gas to power projects.
The most frequent objection to utilizing flare gas is that geographic constraints make it impractical or uneconomic; for example, when a production site is located miles away from the nearest gathering pipeline. The associated petroleum gas (APG) is a by-product of the oil extraction, and something must be done with it to maintain production levels. Without takeaway infrastructure, or a way to use the gas on-site there and then, it’s a waste product that must be flared.
Notice, there are two key factors there: without takeaway infrastructure or a way to use the gas on-site. Those are the two variables in the whether-or-not-to-flare equation that seem fixed but can, in fact, be tweaked to avoid the need for routine flaring.
Remote oil and gas operations that are stranded from takeaway infrastructure are also often remote from power grid infrastructure and rely on on-site generators or turbines to power operations, including artificial lift. Sometimes, these run on diesel, which must be transported to site at significant expense, and are more carbon-intensive than gas. The logical first step then, is to use the produced APG to displace that liquid fuel, either entirely or partially—along with its associated costs.
The trickier decisions come when there is still excess gas that can’t be used this way. What to do then, if not flaring? The list of answers to this is only limited by the extent of human ingenuity. For example, Aggreko has worked on projects where a full modular power station was built on-site, and then took it upon ourselves, including building out the grid infrastructure, on behalf of the local government, to export power. Alternatively, if the gas or power can’t be delivered to end-users, the end-users can be brought to the gas and power. Bitcoin mining operations and data centers are easy operations to co-locate, and are always looking for reliable sources of power.
If the gas is excess to what is needed on site, a virtual pipeline could be employed. The concept of “virtual pipelines” has become more popular in recent years, with advances in midstream technology making it more practical to transport the captured gas by road, either in a liquid or compressed state, negating the need for fixed, expensive infrastructure.
The commonality with both approaches is that they require a solutions-oriented partner with significant engineering capability and experience. Oil and gas are a commodity business, with fortunes tied to the price of oil. But a commodity equipment provider is not what is required here—operators need a partner with the experience and engineering capability to put together a business case and back it up with technology.
Another common objection is that gas quality is often of poor or inconsistent quality. There is truth to this—too many conversations treat “natural gas” as a homogenous substance but, like crude, it appears in all different grades and compositions.
Technology has improved on two fronts to solve this problem. On the one hand, modern gas generators are capable of running on a wider range of gases without compromising performance or durability. On the other, pre-treatment units have improved considerably in terms of capability and cost-effectiveness, and will continue to do so. Additionally, monitoring technology to measure the specification of the gas and adjust the operation of the generators accordingly can help to manage fluctuations in gas quality and composition over the lifetime of a well.
The technology is now there and, once again, it comes back to working with a solutions-oriented partner that can test the gas at-site and design a right-sized solution for the specific situation and present a compelling business case to the operator.
Changing production profiles
It isn’t only quality of gas that can fluctuate over time though; it’s also volume, and this is the third hurdle to overcome.
It is common for the gas production profile to change. That’s not a problem, if during flaring, but if there is a business case around powering operations or a data center, for example, then more certainty around available supply is required.
Again, the answer here is an intelligently designed site-specific solution. Possible technologies could include buffer gas tanks, to store excess gas in times of plenty for later use, or utilizing virtual pipelines to bring in supplementary gas when required. Or, it may be better to convert the excess gas to power and store in batteries instead, levelling out power peaks and troughs when needed. It may even be that a combination of above is the best fit.
What is clear however, is that there is no technical justification for routine flaring left—and the economic and practical justifications are shrinking by the day.