The Quest for Responsibly Sourced Gas
The oil and natural gas industry is unsurprisingly the largest industrial source of methane gas emissions in the US—emitting more methane on its own than the total emissions of all greenhouse gasses from 164 countries combined, according to the Environmental Protection Agency (EPA). In recent years, this exorbitant high emission rate has driven consumers, investors, and government agencies alike to put the oil and gas industry under increased scrutiny. From upstream production through midstream transport, there’s more attention being given to responsibly sourced gas production than ever before.
On the part of oil producers and their customers, the utility companies, they’re eager to embrace the idea of responsibly sourced methane gas. Not only would cleaner production help us meet emissions-reduction goals, branding even some of a company’s output as “responsibly sourced” is a huge draw for investors. The challenge you face in your pursuit of producing more responsibly sourced gas is understanding where the weak points in your operations exist. Only then can you shore up your infrastructure and prevent future methane leaks from occurring.
Methane Leak Monitoring: Intermittent Vs. Continuous
Throughout the oil and gas supply chain, methane leaks have likely been underestimated in the past. This is largely due to insufficient monitoring requirements. Even today, companies can go out once every few months and monitor for potential leaks with a handheld Optical Gas Imaging (OGI) device, and that is considered satisfactory. However, this practice of intermittent monitoring fails to quickly identify fugitive leaks and allow you to resolve them in a timely manner.
Continuous monitoring, on the other hand, allows companies to significantly reduce the amount of methane emissions they’re releasing into the atmosphere by identifying leaks when they happen. When leaks are caught early and repaired quickly, not only does this lead to cleaner production, it saves companies millions of dollars.
A recent report from the Environmental Defense Fund and Carbon Mapper found that, for the last three years, around thirty oil and gas facilities across the Permian Basin in Texas and New Mexico are responsible for emitting the equivalent annual climate pollution of half a million cars. Repairing the leaks at these facilities would save around $26 million in escaped natural gas.
From a due diligence standpoint, continuous leak monitoring is the best choice if you want to produce more responsibility sourced gas, but it’s not necessarily the easier choice. In order to reap the benefits of this practice without overextending your resources, you need to think about leak monitoring strategically.
Where Should You Monitor?
To understand where you need to monitor your operations for methane leaks, you must first determine why equipment leaks in the first place. In general, we can categorize leaks in three ways: those caused by poor design, those caused by human error, and those caused by super emitter events.
Poor Design:
These are the instances in which human interference cannot be blamed for a malfunction. Sometimes, pieces of equipment and their components simply have a faulty design that results in more frequent leaks. An excellent example of this is pneumatic controllers (also called pneumatic devices). These components were installed decades ago to control the flow rate of oil and gas lines. The technology used at the time was ultimately a cheap, quick fix, and the result now is that they leak constantly and require replacement. Other sources of leaks that can be blamed on poor design include compressors and the drivers for compressors.
Human Error:
As long as we have human beings working in the oil and gas industry, the risk of accidents and mistakes will always be present. Whether workers don’t understand or properly follow the established procedures, or a piece of equipment isn’t properly maintained, the consequences of human error should always be of concern. Overtorqued bolts on flanges, improperly installed disk gaskets, and worn down O-rings that were never replaced are just a few examples of human errors that could result in leakage.
Super Emitter Events
Super emitter events are site-based leaks that emit large volumes of methane into the atmosphere over a period of time. According to a recent study, super emitter events represent 8-12% of global methane emissions from oil and gas operations. Sometimes, these episodic events happen by design (condensate flashing, liquids unloadings, etc.), but these intentional events alone could not explain the frequency of super emitter events. Therefore, we have to assume that abnormal process conditions, such as malfunctions caused by poor design or human error, are responsible for at least some super emitter events.
Super emitter events can occur anywhere throughout oil and gas production and transmission, but they most often occur around storage vessels, well completions, casinghead ventings, and liquids unloading.
Creating a Strategy for Continuous Monitoring
The continuous monitoring strategy you employ will differ based on the size of your operations and the resources you have available to dedicate to this undertaking. While large operators have the means to monitor a multitude of upstream and midstream locations, smaller operators may need to be more strategic to ensure monitoring efforts have the most impact. If you’re a small driller, pick out key areas—places with poor design, where mistakes or accidents are most likely to cause leaks, or where super-emitting events are known to occur. These are the locations that will most benefit from leak monitoring sensors. Also, keep in mind that the best solution will leverage a mix of technologies, and will alert technicians to assess the cause and scope of the leak.
When it comes to the sensors themselves, you’ll want to utilize a combination of point sensors and open path sensors. A point sensor will pick up a gas when the molecules encounter it, such as when the wind blows it in the sensor’s direction. You can place point sensors both downwind and upwind of a desired location. While more costly, adding point sensors at multiple heights can be helpful to ensure upward-emitting plumes are not missed by lower point sensors. A pair of open path sensors use a laser to catch the gas as the wind carries it and can be especially useful to monitor methane gas escaping the site’s perimeter, acting as a fall-back to leaks missed by the point sensors due to the wind.
Finally, a monitoring solution is equipped with an anemometer to obtain the speed and direction in which the wind is moving at the time of each methane reading. This provides insight as to which point sensor is nearest to the leak, allowing technicians to begin their assessment. Understanding wind direction is an important aspect of continuous methane monitoring, as a point sensor installed next to a junction may provide a low reading if there is no barrier preventing the wind from blowing the methane away from the sensor.
Unless you’re planning to set up the entire system of methane sensors all at once, you’ll also need a system capable of scaling as you expand your monitoring efforts. At the center of EDG’s continuous methane monitoring solution is our Methane Monitoring Unit (MMU). Each MMU is equipped with a cellular IoT gateway, Li-Ion smart battery charger, and anemometer. The MMU uses a WirelessHART® receiver to monitor a local array of fixed point methane sensors. Any number of MMUs can be monitored through the EDG Client Portal dashboard regardless of their location, and additional MMUs can be onboarded at any time. Similarly, the array of point sensors monitored by a single MMU can easily be expanded.
Once your point sensors are set up, activating continuous methane monitoring is as simple as flipping a switch on each MMU. The cellular IoT gateway within will lock to the strongest available network connection, and sensor data from the fixed point sensors and anemometer will begin to transmit to the EDG Client Portal at user-defined intervals. On the Client Portal’s dashboard, you’re able to monitor wind direction and wind speed at the MMU over time, allowing you to track methane plumes back to the coordinates of individual sensors. This combined data will be at your fingertips in its raw unmodified format, and will help your technicians quantify the size, concentration, and location of a leak. Harness the true power of continuous monitoring by setting up SMS and email alerts in the Client Portal, allowing your team to quickly respond to methane leaks.
The path to more responsibly sourced gas begins with a commitment to continuously monitoring for methane leaks. And with EDG, continuous monitoring can finally be quick, easy, and reliable. Learn more about EDG’s remote IoT monitoring solution or contact us today to start building your continuous monitoring platform.