Measuring vent & greenhouse gas emissions using flow meters

Flow meters for vent & greenhouse gas emissions measurement

Methane is one of the most harmful carbon sources regularly introduced into the atmosphere. Leaks in oil and gas wells are a primary methane source. Accurate greenhouse gas emissions measurements at wells are critical to environmental protections and to comply with environmental regulatory agencies.

Alicat’s portable Whisper-Series gas flow meters are multivariate flow meters which use multiple flow sensors to simultaneously capture pressure, temperature, and flow data in real-time. The battery-powered devices are ideal for field measurement, as they can be inserted inline to validate or verify flows without requiring any wiring or integration with PLCs. Because the Whisper-Series devices introduce minimal pressure drop into the flow lines, they are well-suited for applications flowing ambient air with little pressure differential front one end of the flow line to the other.

Portable flow meters for leak checking in oil and gas wells

Oil and gas wells are often remote and hard to access, and leaks can occur in many places throughout a production site. These leaks present a danger to everyone one site and are extremely wasteful – but they often occur at near-atmospheric pressures, which makes them difficult to detect and measure with accuracy.

Therefore, battery-powered portable measurement equipment presents key advantages: it can function in remote environments without requiring power sources, and can be taken directly to the source of a potential leak for accurate measurement. Versatility is also an important feature, as it minimizes the amount of equipment which must be transported between sites. In addition to multi-variate equipment, devices with high control ranges can measure a wide variety of flow ranges and maintain accuracy. This is particularly important when measuring vent flows from surface casing wells, as the flow rates can vary greatly.

Alicat’s low pressure drop flow meters were designed specifically to test for these types of low-flow leaks with minimal pressure differentials. In addition to their robust, multivariate nature, they have advanced sensors and circuit boards, allowing for a high turndown ratio. You can therefore use a single meter to accurately measure multiple wells with greatly varying flow or leak rates.

Governmental agencies in the United States, and the Alberta Energy Regulator and BC Oil and Gas in Canada, have been using these Alicat meters for leak detection at oil and gas well sites.

Similarly, Wend Energy of Colorado is using Alicat flow meters to measure changes in emissions from storage tanks (another source of methane emissions) before and after they deployed their innovative vapor lock technology.

Durable device design enables usage at gas well sites

The gas components of emissions from natural gas wells will vary with the location and region in which the well is located, and continuously measuring emission flow rates and volumes can help liquid natural gas producers monitor and document changes over time. Alicat devices have been built directly into gas well skids to serve this purpose.

Because of the flammable nature of the natural gas, all instrumentation must meet Class I Division 2 enclosure standards, and should be constructed of 316L stainless steel and appropriate wetted materials to avoid damage by the aggressive gases found in un-combusted natural gas compositions. Flow meters which meet these design parameters can the be regularly used for greenhouse gas emissions measurements.