Flaring has become one of the hot topics in the oil and gas industry to reduce its GHG emissions throughout the value chain. Unfortunately, the industry has not been able or willing to address this topic. However, as outside pressure has been increasing on the industry, flare gas reduction is likely to become a license to operate.
By Lucien Joppen
In the first week of May 2022, the World Bank’s Global Gas Flaring Reduction Partner-ship (GGFR), presented its latest report on flaring. The conclusion of the report was simple and direct: “global progress to reduce gas flaring, the wasteful industry practice of burning natural gas during oil production, has stalled over the last decade. Satellite data compiled and analyzed for GGFR’s 2022 Global Gas Flaring Tracker Report shows that 144 billion cubic meters (bcm) of gas was flared at upstream oil and gas facilities last year. This is the equivalent of nearly 400 million tonnes of carbon dioxide (CO2).”
A brief look at the aforementioned report shows, however, that oil production and gas flaring seem to have been decoupled since the early 2000’s. However, the amount of gas being released into the atmosphere still is significant.
GGFR
The World Bank’s Global Gas Flaring Reduction Partnership (GGFR) is a multi-donor trust fund composed of governments, oil companies, and multilateral organizations committed to ending routine gas flaring at oil production sites across the world.
The initiative helps identify solutions to the array of technical and regulatory barriers to flaring reduction. To achieve this, GGFR develops country-specific flaring reduction programs, conducts research, shares best practices, raises awareness, secures global commitments to end routine flaring, and advances flare measurements and reporting.
Methane
The composition of these gases varies, depending upon the source of the gas going to the flare system. Associated gases released during oil-gas production mainly contain natural gas, mostly (90 per cent) consisting of methane (CH4) with ethane and small amounts of other hydrocarbons. Inert gases such as N2 and CO2 may also be present.
As methane dominates this mix, gas flar-ing contributes to the CO2 footprint of the industry. “The methane emissions resulting from the inefficiency of the flare combustion contribute significantly to global warming”, the World Bank states. “This is particularly so in the short to medium term as, according to the Intergovernmental Panel on Climate Change, methane is over 80 times more powerful than carbon dioxide as a warming gas on a 20-year timeframe. On this basis, the annual CO2 equivalent emissions are increased by nearly 100 million tons.”
Zero routine flaring
It should come as no surprise that GGFR aims to reduce gas flaring to mitigate its impact on climate change. In 2015, the body launched the Zero Routine Flaring initiative, which should end routine flaring no later than 2030.
The practice of routine flaring – one of the three types of flaring – is defined as the ‘continuous burning of (large) amounts of associated petroleum gas during the extraction of crude oil. Routine flaring may be permitted for a specified duration by a regulatory and compliance authority.’ Apart from this avoidable flaring, there are also flaring modes that are necessary, for example process flaring (during well testing in the exploration phase) or emergency flaring which only occurs during unforeseen incidents and needs to be deployed to guar-antee safe operations.
Constraints
Zooming in on routine flaring, there are various constraints as why this practice still is prevalent. First of all, the economics have not been favourable. The relative low volumes (see the dispersion of a plethora of production locations (on and offshore) and the lack of transportation infrastructure have made capturing gas more expensive than flaring. Needles to say, with present-day gas prices this economic outlook might change. Secondly, there seems to be a lack of appropriate regulation and political will, the World Bank states. One of GGFR’s goal’s is to work closely with governments and industry associations to address these shortcomings and create a global framework that is conducive to reduce gas flaring, including creating and harmonizing monitoring and reporting standards. As has been documented, under-reporting is likely to happen as there can be varying measurement methods, limited oversight or practical issues such as a shortage in (measuring) equipment.
Strictly enforced regulations
There are countries that have successfully addressed routine gas flaring, which proves that a concerted effort is effective. Kazakhstan has achieved the largest overall flare reduction of all monitored countries in the last 10 years, reducing absolute flaring from 4 bcm in 2012 to 1.5 bcm in 2021, thanks to strictly enforced regulations, coupled with a domestic gas market that incentivizes associated gas recovery. Meanwhile, Colombia reduced flaring from 1 bcm in 2012 to 0.3 bcm in 2021, enabled by domestic gas utilization and strong regulations that prohibit any gas from being wasted.
However, from the Top 10 flaring countries, the United States has been the only one to have successfully reduced flare volumes while increasing production over the last decade. The US has done so by focusing on flaring intensity: the volume of gas flared per barrel of oil produced by 46 percent.
Technology developments
As mentioned in the previous paragraphs, gas recovery and utilization is needed to reduce routine flaring. Potential business cases depend on market conditions but also on technology development which could lower the economic threshold.
Small-scale GTL (gas-to-liquids) could be such a technology. It involves production of commodities such as naphtha, diesel, methanol, and waxes, in capacities ranging between few hundreds to a few thousands of barrels per day. The setup uses modular and portable designs of GTL plants, that can be installed easily at an oil production site. Currently, these modular production plants are operational at shale gas production fields.
Small-scale LNG can also be an alternative to curb gas flaring by turning it into a marketable product. These plants are best suited for oilfields that flare a large volume of natural gas and are located in the vicinity of LNG bunkering hubs.
In short, there are encouraging signs that routine flaring can be mitigated. However, historical data show that progress is slow, to say the least. Given the (rising) outside pressure (from NGO’s, governmental) on the oil and gas industry, this topic is likely to stay on the agenda. Therefore, it needs to be properly addressed.
Flaring and valve inspection: the 80/20 rule
Gas flaring, the process of burning-off associated gas from wells, hydrocarbon processing plants or refineries, either as a means of disposal or as a safety measure to relieve pressure. It is now recognized as a major environmental problem, contributing an amount of about 150 billion m3 of natural gas is flared around the world, contaminating the environment with about 400 Mt CO2 per year.
Regardless of unwanted or wanted shut-down, sweeping gases of piping, need for depressurizing piping and equipment, and bad operation, one of the main sources of flaring is flaring system valves include both relief and non-relief valves. Safety relief valves are usually inspect according to the plant specifications, RBI planning or related codes and standards like NBIC NB-23 Part4, EEMUA 188, API 570/510/576/527/RP 524. Non-relief valves on the hand are not easy to inspect both during operation and shut-downs.
There are hundreds valves in one flaring system, so it is not easy to inspect and overhaul all of them during shut-downs. The best idea is to know the amount of leakage each valve has, and sort them. Prioritization according to the 80/20 rule is an effect act in reduction of flaring. It is important to sort hundreds valves in a short time with the least cost. First we need to know how to inspect valves when they are in service. There are some methods for on-stream (in-service) inspecting of valves:
Touching
By touching a valve, especially in the gas services, due to the pressure drop on the down stream, the fluid becomes cooler. The more leakage the valve has, the cooler it becomes.
Hearing
When there is a leakage in the valve, a sharp voice usually could be heard. Sometimes you need to put your ear on the valve!
Ultrasonic Measurement
Although when it comes to UT, inspection of welds cross our minds, it is very useful for measuring flow that transmit through the line. We know that velocity speed depends on the density of a medium, so, by increasing flow, the density of the medium gets bigger and velocity of sound increases. This method could be conducted in 2 different ways, one is portable and the other is in line. The portable form is usually used for inspection or random checking of a line and the in line form is usually used as a flow meter or flow transmitter.
Thermographic inspection
Thermography is used when there is thermal gradient in an equipment or in the tiny spaces with different temperature. It uses electromagnetic to differentiate the temperature and shows it in different colors. This method is mostly used for inspection of steam-traps. Thermography is partially cheaper method than the UT, however is it faster that it. On the other hand, UT is more accurate than thermography and the plan for maintenance of the valves has to be based on the flow leakage sent to the flaring system. It seems initial filtration could be based on the thermography and the final sorting of the nominated valves could be based on the UT method. In the end, 80/20 rule which means by maintenance of 20 per cent of valves, you could reduce 80 percent of flaring will help you to save cost and time!
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This Featured Story is an article from our Valve World Magazine June 2022 issue. To read other featured stories and many more articles, subscribe to our print magazine.
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