Fugitive gas emissions
[3] Approximately 1-3% of methane leakage cases in unconventional oil and gas wells are caused by imperfect seals and deteriorating cement in wellbores.
[18] It has been suggested that 62% of atmospheric ethane originates from leaks associated with natural gas production and transportation operations.
[20] It has also been suggested that ethane emissions measured in Europe are affected by hydraulic fracturing and shale gas production operations in North America.
[4][24] An aircraft survey in northeastern British Columbia indicated emissions emanating from approximately 47% of active wells in the area.
[8] The same study suggests that actual methane emissions may be much higher than what is being reported by industry or estimated by government.
For small-scale measurement projects, infrared camera leak inspections, well injection tracers, and soil gas sampling may be used.
Since different types and maturity levels of natural gas have different δ13CH4 signatures, these measurements can be used to determine the origin of methane emissions.
[19] Policies regulating reporting of fugitive gas emissions vary, and there is often an emphasis on self-reporting by companies.
[1] According to the BCOGC, surface casing vent flow is the major cause of leakage in wells at 90.2%, followed by gas migration at 7.1%.
Policies can include emission caps, feed-in-tariff programs, and market-based solutions such as taxes or tradeable permits.
[28] Canada has enacted policies which include plans to reduce emissions from the oil and gas sector by 40 to 45% below 2012 levels by 2025.
[9][16] Once emitted, methane is also oxidized by water vapour and increases carbon dioxide concentration, leading to further climate effects.
[17] Costs related to implementation of policies designed to reduce fugitive gas emissions vary greatly depending on the geography, geology, and hydrology of the production and distribution areas.
[14] Often, the cost of reducing fugitive gas emissions falls to individual companies in the form of technology upgrades.
This means that there is often a discrepancy between companies of different sizes as to how drastically they can financially afford to reduce their methane emissions.
