Methane and the Oil and Gas IndustryAccording to the United States Environmental Protection Agency (EPA), methane is the second most prevalent greenhouse gas emitted in the US from human activities (Overview of Greenhouse Gases, 2016). Globally, over 60% of total methane emissions come from human activities such as industry, agriculture, and waste management. Pound for pound, the comparative impact of methane on climate change is more than 25 times greater than carbon dioxide over a 100 year period (Overview of Greenhouse Gases, 2016). This makes methane one of the most potent greenhouse gases, and a large contributor towards global climate change. Methane is the primary component of natural gas, and is emitted to the atmosphere during the production, processing, storage, transmission, and distribution of natural gas and crude oil. The oil and gas sector is a key source of methane emissions in Canada, the US, and around the world. Methane emissions in 2014 from Alberta’s oil and gas sector accounted for 70% of provincial methane emissions. 48% of these methane emissions came from venting, 46% came from fugitives, and the remaining 6% were from flaring or other sources (Reducing methane emissions, 2016).
Methane as an OpportunityIn an effort to combat climate change caused by greenhouse gases, regulatory bodies at all levels are advocating emissions control and reduction. Due to the potency of methane as a greenhouse gas, reducing methane emissions is a key opportunity to make sizeable greenhouse gas reductions cost-effectively. At the historic Paris Agreement in December 2015, the International Energy Agency identified minimizing methane releases from upstream oil and gas production as one of the five key opportunities to keep the global temperature rise to below two degrees Celsius (Canada-US Joint Action to Reduce Methane Emissions, 2016).
Federal RegulationsIn March 2016, The United States and Canada announced a joint commitment to reducing emissions. Canada has committed to reduce methane emissions from the oil and gas sector by 40-45% below 2012 levels by 2025. To implement this commitment, the federal government will introduce regulations to reduce methane emissions, and require organizations to report on all potential sources of methane across the business including both venting and fugitive emissions. The regulations would apply to oil and gas facilities that are responsible for the extraction, production and processing, and transportation of crude oil and natural gas. These include oil and gas wells and batteries, natural gas processing plants, compressor stations, and supporting pipelines. Environment and Climate Change Canada (ECCC) will be drafting regulatory requirements designed to cover key methane emissions from the following sources:
- Venting from wells and batteries (including associated gas at oil facilities)
- Storage tanks
- Pneumatic devices
- Well completions
- Fugitive equipment leaks
Provincial RegulationsThe Alberta government has also committed to reducing methane emissions from oil and gas operations by 45% from 2012 levels by 2025. Alberta’s reduction target and timeline match the commitments announced by Canadian and American federal governments, in an effort to maintain consistency with Alberta’s approach of protecting economic competitiveness through alignment with North American environmental standards. According to the government of Alberta, methane reductions will be achieved using the following approaches:
- Applying new emissions design standards to new facilities
- Improving measurement and reporting of methane emissions, as well as LDAR requirements
- Developing a joint initiative on methane reduction and verification for existing facilities. The initiative will be backstopped by regulated standards in 2020 to ensure that the 2025 target is met.
Quantifying Methane EmissionsMethane emissions can be broadly classified into two categories – emissions caused by day to day operations and emissions caused by equipment fugitives (leaks). Understanding the various sources of emissions is a key first step in starting to track and report emissions. Recapping the items subject to regulations by the ECCC mentioned earlier, this section analyzes each item with respect to both operational and fugitive emissions. A few additional categories have been included, referenced from the EPA’s information collection request that resulted from the US government’s commitment to address emissions reduction in March 2016 (The Oil and Natural Gas Industry: Information Collection Request, 2016).
|Source||Device Usage||Typical Emissions|
|Pneumatic Devices and Controllers||A Pneumatic Controller is a mechanical device designed to measure temperature or pressure and transmit a corrective air signal to the final control element (What is a Pneumatic Controller?, 2001).||As part of normal operation, pneumatic devices release or bleed natural gas to the atmosphere. (Options For Reducing Methane Emissions From Pneumatic Devices In The Natural Gas Industry, 2006)|
|Storage Tanks||Storage tanks are used for a variety of processes in the oil and gas industry||Flash losses can occur when crude is transferred from a gas/oil separator at higher pressure to a storage tank at atmospheric pressure. Working losses occur when crude levels change or when the tank is agitated. Standing losses occur with daily and seasonal temperature and pressure changes. (Technology Transfer Workshop, 2006)|
|Liquids unloading||In mature gas wells, the accumulation of liquids in the well can occur when the bottom well pressure approaches reservoir shut-in pressure. This accumulation of liquids can impede and often halt gas production, and removal of fluids (i.e., liquids unloading) is required in order to maintain production (US EPA Office of Air Quality Planning and Standards (OAQPS), 2014)||When liquid loading occurs, several strategies are typically used by operators to unload the liquids. One of the more common activities, known as well blowdowns, involves shutting in the well to allow bottom hole pressure to increase, then venting the well to the atmosphere (known as well blowdowns). This activity produces substantial emissions. (US EPA Office of Air Quality Planning and Standards (OAQPS), 2014)|
|Pumps||Pumps are used in a number of oil and gas processes to move ﬂuids from one point to another.||Circulation pumps in glycol dehydration units and chemical transfer pumps are often powered by pressurized natural gas. As part of their normal operation, these devices will vent methane gas to the atmosphere. (Convert Gas-Driven Chemical Pumps to Instrument Air, 2004)|
|Reciprocating compressors||A reciprocating compressor is a packing system that uses pistons driven by a crankshaft to deliver gases at high pressure (Reciprocating Compressor, 2016). They are used in oil refineries, gas pipelines, chemical plants, and natural gas processing plants.||Reciprocating compressors in the natural gas industry leak natural gas during normal operation. Areas of high leak frequency include flanges, valves, and fittings located on compressors. The highest volume of gas loss, however, is associated with piston rod packing systems (Reducing Methane Emissions From Compressor Rod Packing Systems, 2006)|
|Centrifugal compressors||Centrifugal compressors achieve pressure by adding kinetic energy to a continuous flow of fluid through the rotor. They are used in a variety of applications including gas turbines, diesel engine chargers, pipeline compressor stations, and oil refineries, petrochemical and chemical plants. (Centrifugal Compressor, 2016)||The majority of methane emissions occur through seal oil degassing which is vented to the atmosphere (Reducing Methane Emissions from Centrifugal and Reciprocating Compressors, 2010)|
|Well Completion||Gas wells in tight formations and coal beds require hydraulic fracture It is necessary to clean out the well bore and formation. After well completion, operators produce to an open pit or tank to collect sand, cuttings, and fluids for disposal (Reducing Methane Emissions from Production Wells: Reduced Emission Completions , 2010)||The natural gas produced from the first start is flared as it contains impurities associated with the initial fracturing (sand, cuttings, etc.) (Reducing Methane Emissions from Production Wells: Reduced Emission Completions , 2010)|
Fugitive EmissionsThe LDAR best practices guide published by the EPA gives a further breakdown on identifying and classifying the types of fugitive emissions (Leak Detection and Repair: A Best Practices Guide, 2014) .
|Source||Device Usage||Typical Leak Scenario|
|Pumps||Used to move ﬂuids from one point to another. Two types of pumps extensively used in petroleum reﬁneries and chemical plants are centrifugal pumps and positive displacement, or reciprocating pumps||Leaks from pumps typically occur at the seal|
|Valves||Used to either restrict or allow the movement of ﬂuids. Valves come in numerous varieties and with the exception of connectors, are the most common piece of process equipment in industry.||Leaks from valves usually occur at the stem or gland area of the valve body and are commonly caused by a failure of the valve packing or O-ring.|
|Connectors||Components such as ﬂanges and ﬁttings used to join piping and process equipment together. Gaskets and blinds are usually installed between ﬂanges.||Leaks from connectors are commonly caused from gasket failure and improperly torqued bolts on ﬂanges.|
|Sampling Connections||Sampling connections are utilized to obtain samples from within a process.||Leaks from sampling connections usually occur at the outlet of the sampling valve when the sampling line is purged to obtain the sample.|
|Compressors||Increase the pressure of a ﬂuid and provide motive force. They can have rotary or reciprocating designs (detailed above).||Leaks from compressors most often occur from the seals.|
|Pressure Relief Devices||Safety devices designed to protect equipment from exceeding the maximum allowable working pressure. Pressure relief valves and rupture disks are examples of pressure relief devices.||Leaks from pressure relief valves can occur if the valve is not seated properly, operating too close to the set point, or if the seal is worn or damaged. Leaks from rupture disks can occur around the disk gasket if not properly installed.|
|Open Ended Lines||Pipes or hoses open to the atmosphere or surrounding environment||Leaks from open-ended lines occur at the point of the line open to the atmosphere and are usually controlled by using caps, plugs, and ﬂanges. Leaks can also be caused by the incorrect implementation of the block and bleed procedure.|
About iSolutionsiSolutions is an Alberta based data management consulting company that specializes in designing, implementing and supporting real-time, historian based, reporting and integration solutions for Oil/Gas and Utility companies. Our implementations allow clients to make educated, site specific production and operational decisions based on the analysis of real time data from integrated field and plant systems. We specialize in historian system design, reporting and analysis tool implementations, production data integration solutions and custom software development. For more information, please contact Anil Datoo at 403.472.9804 or email him at email@example.com. Here are some of the other ways in which we can help your organization achieve environmental awareness and ready itself for the new environmental regulations.
iSolutions Emission Reporting OfferingLDAR proposes a 6 step program structure in which identifying and monitoring key components comes before any reparative actions are taken. In order to properly achieve emissions reduction targets organizations must consolidate the sources of emissions information from across the enterprise and consolidate it in a coherent manner. iSolutions has built a tracking and reporting solution that can be used to do exactly this. Presenting a hierarchy of assets across geographies, the solution tracks, manages, and reports total emissions broken down into operational and fugitive sources, as well as target numbers across the enterprise. The solution enables customers to track progress and measure actual outputs compared to target outputs. Mindful of the vast array of emissions sources and scenarios mentioned above, our configurable solution intends to provide a complete GHG emissions picture for your enterprise. Environmental data for each operational and fugitive source are integrated into the comprehensive solution, capturing key asset details and such as vendor details, P&ID tagging, repair history, and leakage/remediation history. Our solution offering simplifies integration of numerous data sources across your enterprise in order to form a single source of truth for greenhouse gas reporting. This includes sources such as but not limited to:
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