In this article, we explained measuring and reducing methane, the sources, the strategies, the challenges, we also talked about how to reduce methane.
Definition
Measuring and reducing methane emissions in oil and gas operations refers to the process of accurately identifying, quantifying, and then decreasing the release of methane, a potent greenhouse gas, from oil and natural gas extraction, processing, and distribution activities. This is crucial because methane is significantly more effective at trapping heat in the atmosphere than carbon dioxide over a shorter period, making its rapid reduction vital for slowing near-term global warming and achieving climate targets.
Sources of Methane Emissions in Oil and Gas Operations
Methane emissions in the oil and gas sector are broadly categorized into three main types:
Venting: Intentional release of natural gas directly into the atmosphere. This occurs due to:
Pneumatic Devices: Many control devices (e.g., valve controllers, pumps) at oil and gas facilities are powered by natural gas pressure, which is then vented to the atmosphere.
Process Venting: Routine or non-routine releases from equipment such as dehydrators, separators, storage tanks, and during well completions or workovers.
Unlit Flares: When flares malfunction or are unlit, gas intended for combustion is simply vented.
Associated Gas: In oil production, natural gas often comes up with the oil (associated gas). If there’s no infrastructure to capture or utilize it, it may be vented.
Flaring: The controlled burning of natural gas that cannot be economically collected, transported, or utilized. While flaring is intended to convert potent methane into less potent CO
2, it is often inefficient, especially with older or poorly maintained flares. Incomplete combustion results in the release of significant amounts of unburnt methane and black carbon. Flaring is a major issue in countries like Nigeria, which consistently ranks among the top global gas-flaring nations.
Fugitive Emissions (Leaks): Unintentional releases of methane from equipment, pipelines, and infrastructure due to wear and tear, corrosion, poor maintenance, or design flaws. These can range from small, persistent leaks to large, intermittent “super-emitter” events. Common sources include:
Compressor Seals: Leaks from the seals of reciprocating and centrifugal compressors.
Valves and Connectors: Leaks from flanges, valves, and other connections.
Storage Tanks: Methane “flashing” off crude oil or condensate in storage tanks.
Pipelines: Leaks from aging or damaged pipelines.
Measuring Methane Emissions
Accurate measurement is the foundation for effective mitigation. Without knowing where and how much methane is being emitted, reduction efforts cannot be effectively targeted or verified. Measurement technologies are rapidly evolving, moving from traditional estimation methods to more precise, direct quantification.
- Traditional Approaches:
Emission Factors: Applying average emission rates per piece of equipment or activity type, multiplied by the number of equipment pieces or activity level. This approach is prone to significant uncertainties as it doesn’t account for variability in equipment performance or “super-emitter” events.
Engineering Calculations: Based on process design, flow rates, and gas composition.
- Advanced Measurement Technologies (Top-Down and Direct Measurement):
New technologies offer increasingly accurate and granular data:
Ground-Based Methods:
Optical Gas Imaging (OGI) Cameras: Handheld or vehicle-mounted infrared cameras that visualize otherwise invisible methane plumes. Excellent for leak detection and pinpointing sources, but don’t quantify emission rates directly. They are a cornerstone of Leak Detection and Repair (LDAR) programs.
Portable Gas Detectors/Analyzers: Handheld devices that provide real-time concentration readings. Can be used for “sniffing” surveys to locate leaks.
High-Volume Samplers (Hi-Flow Samplers): Used to quantify emissions from specific sources by capturing and measuring the flow rate of the emitted gas.
Flux Chambers/Enclosures: Small chambers placed over potential emission sources (e.g., wellheads, soil) to capture and measure methane flux over a short period.
Acoustic Sensors: Detect the sound produced by gas leaks, useful for detecting underground pipeline leaks, though not for quantification.
Tracer Gas Release: Releasing a known quantity of a tracer gas (e.g., acetylene) and then measuring the dilution of both the tracer and methane downwind to calculate methane emission rates.
Airborne Methane Sensors: Mounted on planes or helicopters, these sensors can cover large areas rapidly, identifying and quantifying large emission sources or “super-emitters.” Examples include LIDAR (Light Detection and Ranging) and spectroscopic sensors.
Drone-Mounted Sensors: Offer flexibility and access to difficult-to-reach areas, providing high-resolution data for site-specific surveys.
Satellite-Based Methods:
Satellite Constellations: Several satellites (e.g., Sentinel-5P, GHGSat, MethaneSAT) are now capable of detecting and quantifying large methane plumes globally. They provide continuous, wide-area monitoring, helping to identify “super-emitter” events and regional trends, often without the need for ground access. While providing large-scale coverage, their spatial resolution might be limited for pinpointing individual small leaks.
Continuous Monitoring Systems (CMS):
Permanently installed sensors at facilities provide real-time, continuous monitoring of methane concentrations, allowing for immediate detection of leaks and rapid response. This is becoming a best practice for critical infrastructure.
Data Analytics and Verification:
Raw measurement data needs sophisticated analysis to accurately quantify emissions and identify trends. This often involves:
Machine Learning and AI: To process large datasets from continuous monitoring or satellite imagery, identifying patterns and anomalies.
Measurement, Reporting, and Verification (MRV) Systems: Robust MRV frameworks are essential to track progress, ensure transparency, and inform policy.
Reducing Methane Emissions
Effective methane reduction strategies involve a combination of preventing releases, capturing emissions, and improving operational efficiency.
- Leak Detection and Repair (LDAR) Programs:
Regular Surveys: Implementing systematic and frequent surveys of all equipment using OGI cameras or other detection technologies.
Prompt Repair: Establishing a rapid response protocol to repair identified leaks, prioritizing larger leaks (super-emitters).
Data Management: Tracking leak locations, repair times, and estimated reductions to evaluate program effectiveness.
Eliminating or Minimizing Venting:
Pneumatic Device Replacement: Replacing high-bleed pneumatic controllers with low-bleed, no-bleed (zero-bleed), or instrument air/electric-powered alternatives. Solar-powered electric pumps are an excellent solution for off-grid sites.
Reduced Emissions Completions (RECs) / Green Completions: During well completions and workovers, using specialized equipment to capture natural gas (including methane) and direct it into pipelines for sale or use, instead of venting or flaring.
Closed Vent Systems: Designing systems to prevent gas from venting directly to the atmosphere by routing it to a capture system or flare.
- Flaring Reduction and Optimization:
Gas Gathering and Processing Infrastructure: Investing in infrastructure to capture, compress, and transport associated gas to market, eliminating the need for flaring. This is particularly crucial in regions like the Niger Delta, where gas flaring remains a significant issue.
Gas-to-Power Projects: Utilizing associated gas to generate electricity for on-site use or for sale to the grid, transforming a waste product into a valuable energy source.
Re-injecting excess gas back into reservoirs for storage or enhanced oil recovery.
Improved Flare Efficiency: For unavoidable flaring, ensuring flares are well-maintained and operating at high combustion efficiency (e.g., maintaining proper gas-to-air ratios, ensuring continuous ignition) to minimize unburnt methane. The aim is often 98% destruction efficiency, but real-world performance can be much lower.
Upgrading and Maintaining Equipment:
Replacing Old Equipment: Phasing out older, leak-prone equipment with modern, low-emission alternatives.
Regular Maintenance: Implementing comprehensive maintenance schedules for compressors, valves, pumps, and pipelines to prevent leaks and ensure efficient operation.
Dry Seal Technology for Compressors: Replacing wet seals on centrifugal compressors with dry seals, which significantly reduce methane emissions.
Improved Rod Packing in Reciprocating Compressors: Regularly replacing or upgrading rod packing to minimize leaks.
Operational Practices:
Minimizing Blowdowns: Reducing the frequency and volume of intentional depressurization events (blowdowns) and, where possible, routing the gas to capture systems.
Training and Awareness: Educating personnel on best practices for methane emission reduction, leak detection, and rapid response.
Process Optimization: Analyzing operational processes to identify and eliminate sources of unnecessary methane release.
Regulatory and Policy Landscape
Governments and international bodies are increasingly implementing regulations and incentives to drive methane reductions:
Reporting Requirements: Requiring companies to measure and report their methane emissions, often publicly.
Incentives: Providing financial incentives, grants, or tax breaks for companies investing in methane reduction technologies and practices. The U.S. Inflation Reduction Act, for instance, includes a Methane Emissions Reduction Program (MERP) with funding and a waste emissions charge.International Initiatives: The Global Methane Pledge, signed by over 155 countries including Nigeria, aims for a collective 30% reduction in global methane emissions by 2030 (from 2020 levels)
Challenges and Opportunities
Cost: Initial investment in new technologies and infrastructure can be significant, especially for smaller operators or in developing countries.
Data Gaps: Despite advancements, accurately attributing and quantifying all methane sources, especially intermittent super-emitters, remains challenging.
Aging Infrastructure: Many oil and gas facilities globally are old and prone to leaks, requiring substantial upgrades.
Remote Locations: Accessing and monitoring facilities in remote or offshore locations can be difficult and expensive.
Policy Enforcement: Effective enforcement of regulations is crucial, particularly in regions with weaker governance.
Opportunities:
Climate Mitigation: Methane reduction offers one of the fastest and most cost-effective pathways to achieve near-term climate benefits.
Improved Safety: Reducing leaks improves operational safety by minimizing explosion risks.
Enhanced Public Health: Decreased venting and flaring reduces the release of other harmful pollutants, improving air quality for local communities (e.g., in the Niger Delta).
Technological Innovation: The focus on methane reduction is driving innovation in detection, quantification, and mitigation technologies.
Access to Finance: Countries and companies demonstrating strong methane mitigation efforts may gain better access to green finance and align with stricter ESG (Environmental, Social, and Governance) standards from international investors.
Conclusion
Methane emissions are both a major contributor to climate change and a solvable problem. In the oil and gas sector, a significant portion of methane leakage can be stopped with existing technology and reasonable investment. As scientific tools evolve and public pressure intensifies, the pathway toward a low-leak, low-carbon energy future becomes increasingly viable.