Emissions Management Techniques
Pneumatic Controller Program
A pneumatic controller is a process control device that uses natural gas generated at a well facility to operate mechanical devices that control pressures, temperatures, and fluid levels in production process equipment. Continuous and high-bleed pneumatic controllers are one of the largest contributors of methane and VOC emissions in oil and gas production. Since 2016, Continental has installed low- and intermittent-bleed pneumatic controllers at new facilities and has retrofitted many existing facilities with lower bleed controllers resulting in substantial reductions in our methane intensity over the last four years. In addition, CLR is continuously researching application of new controller technologies to improve operational efficiency and reduce emissions.
Manual Liquids Unloading
As liquids accumulate in a natural gas well, the weight of the liquid – primarily formation water – becomes greater than the gas velocity and eventually slows or stops the production of natural gas. These wells often need to remove, or unload, the accumulated liquids so gas production is not inhibited. Manual liquids unloading is an operation to temporarily divert the flow of accumulated liquids from the well straight to a low-pressure tank equipped with an atmospheric vent, which allows wellbore pressure to change and liquids to rise to the surface without the assistance of automated equipment.
Without careful monitoring, the liquids unloading process can allow some methane and VOCs to be released into the atmosphere. Therefore, consistent with industry best practices, Continental monitors the manual unloading process on-site or in proximity and returns the well’s flow to the production equipment and normal operating scenarios as soon as possible.
Leak Detection and Repair (LDAR)
Continental complies with federal LDAR requirements to reduce emissions at applicable facilities, and our voluntary program takes it a step further and includes LDAR inspections for emissions at many facilities not covered by federal requirements. For example, we conduct optical gas imaging (OGI) inspections; audible, visual, and olfactory (AVO) inspections; and daily emission-control device checks at all facilities in Oklahoma, North Dakota, Montana, and Wyoming. Furthermore, while federal LDAR rules require identified leaks to be repaired within 30 days, Continental has an internal expectation to repair such leaks within 10 days. In our most recent reporting year, nearly 100% of LDAR related repairs have been completed within 10 days.
Continental is a leader in gas capture and strives to minimize the flaring of gas from our operations. We are constantly working to ensure midstream companies understand our development forecast and to make the necessary operational adjustments to capture the vast majority of our natural gas production. According to the North Dakota Petroleum Council, as of 2019, industry had collectively spent an estimated $19 billion on infrastructure for capturing residual gas. As a result of these efforts, Continental has increased its gas capture from 88.4% to 98.3% in the past 5 years.
Thermal Incineration of Gas (TIG)/Flaring
TIG, often referred to as flaring, is the process of burning off natural gas in a safe and controlled manner when there is an emergency or gas capture is not possible. TIG creates carbon dioxide and water by burning natural gas. TIG is preferable to venting since carbon dioxide has a lower global warming potential than methane. Intermittent TIG may occur as a result of routine well testing, production facility process shutdowns, or facility and pipeline infrastructure maintenance. Increased TIG in some unconventional plays has resulted from pipeline capacity constraints, lack of infrastructure, restrictive state and local regulations, or opposition and legal challenges by environmental activists to the permitting and construction of new natural gas pipelines.