Every barrel of oil or gas equivalent has a carbon overhead because of the energy consumed to produce it, the flaring of gas, and the leakage or venting of methane from well infrastructure. In 2019 upstream activities released ~2.9 GtCO₂e, or ~6% of the total annual greenhouse gases produced by human activity. Total hydrocarbon production in that year was ~60 Bboe, resulting in a ‘carbon per barrel’ overhead of ~48 kgCO₂e per barrel equivalent. Clearly, this overhead needs to be cut drastically if we are to avoid the dystopian scenario of runaway climate change.

What can operators do to reduce emissions? One answer lies in understanding the true dynamic behavior of well systems with through-barrier diagnostics. Diagnostics that reach beyond the traditional confines of the wellbore and see more can help operators reduce energy use and resulting emissions in a wide range of scenarios.

Energy from turbines and diesel engines accounts for more than 70% of the CO₂ emissions from upstream operations. Through-barrier diagnostics can help operators identify energy inefficiencies in a number of ways. For example, one of the largest demands on upstream energy comes from powering water injection pumps to maintain reservoir pressure. Well and formation integrity issues can divert water from the target, increasing the amount of water needed and wasting resources. Through-barrier diagnostics can reveal diverted water behind casing, aiding remediation and ultimately reducing injection rates and associated emissions.

Gas flaring accounts for roughly ~30% of upstream oil related CO₂ emissions. If the associated gas that is produced alongside oil cannot be utilized, it is burned. The reasons could be technical, regulatory or economic, and even though the industry is working to reduce flaring, it remains a global issue. Through-barrier diagnostics can’t provide an alternative to flaring, but it can help track sources of unwanted gas to aid remediation, enabling operators to limit unwanted gas production and flaring.

At 1.9 GtCO₂e per year, methane is the largest contributor to upstream carbon emissions. Methane is a potent and insidious contributor to the greenhouse effect, partly because methane has ~30x the warming effect of CO₂, and fugitive leaks from active and abandoned wells can go unnoticed for years. However, a major source of methane is intentional venting. Gas leaks inside the well system can build up in between casings, and this may be vented if the pressure exceeds safe levels. Through-barrier diagnostics can locate the source of gas within the well system, informing remediation decisions and ultimately helping to reduce methane venting.