Guest Editorial: Metrics and Measurements of Methane Emissions: How Are We Really Doing?

The hardest part of petroleum engineering is not the calculations or the inherent uncertainty. It is guarding against cognitive biases.

Avoiding bias begins with reliable measurements of appropriate questions, and therein lies the first of two problems with understanding our industry’s methane emissions:

The most common measure of methane emissions obscures poor gas-handling performance.

The second-biggest problem—availability bias—builds on this misstep to compound our misunderstanding of our industry’s performance by ignoring the bulk of the independent evidence about our performance.

Actionable insight—or misdirection—begins with the choice of measurement. Jim Collins’ bestseller, Good to Great, enshrined the now ubiquitous concept of key performance indicators. The measurement must be useful for discriminating better from worse in a way that can affect choices to achieve the goals. In this case, the objective is to reduce significantly methane emissions below historical levels. In Collins’ words, an appropriate measure must show the “brutal truth.”

Of course, natural gas is a valuable and useful product with strong, inherent, long-standing incentives against waste. But still, both venting and flaring have persisted at levels detrimental to near-term climate deformation, regulatory risk, and industry credibility. An appropriate measure would highlight where improvements can be made on top of the existing economic and regulatory structures. A measurement of emissions should differentiate good operations from bad operations when comparing like to like, and it should lead to improvements over the baseline.

Ironically, our industry of technical professionals often relies on a unit of measurement which obscures differences and conflates economic drivers with operational excellence: methane intensity. Although often expressed as a percentage, this unit compares energy vented (without regard to flaring) against energy captured, including crude oil and condensate.

Adding liquids to the denominator always drives the measurement value down without saying anything about the excellence of gas handling. It may measure the overall loss of energy to society, but it does not highlight shortcomings and does not help guide improvement.

Of course, what matters most directly for the climate is the mass of methane wasted.

At a small scale, the mass of methane in 1 Mcf of natural gas is calculated by multiplying 19.2 kg/Mcf by the methane concentration. Working in the other direction, 1 kg/hr of methane converts to about 1.5 Mcf/D of natural gas at an 84% methane content. Because methane is so much more potent in the short term than CO2, that 1.5 Mcf of natural gas has the same pollution effect as 4,500 lb of CO2. That is, pollution equivalent to the mass of a light-duty truck can be released each day from a single, small oil well.

At scale, emissions are measured by the benign-sounding unit of “terragram,” each of which can cause as much climate deformation over the next 20 years as 187 billion lb of CO2. The upstream industry in Texas alone emits six or more of these colossus units every year.