SF6 (sulphur hexafluoride) and PFCs (per fluorocarbons) are gas molecules, which are being used as the state-of-the-art tracers in tracer technology programmes aimed at hydrocarbon reservoir characterization and efficient oil recovery. Despite the term “tracers”, these chemicals are employed for the above purposes in quantities that are significant enough to represent e.g. in the case of Norway 5% of the total annual SF6 consumption. Although SF6 and PFCs are anthropogenic compounds originally used as substitutes for ozone depleting substances, their high Global Warming Potential (GWP) and extremely long lifetimes in the atmosphere constitute them very potent greenhouse gases (GHG).
(i) the pressure of the environmental authorities on the oil industry to reduce and even ban the use of such chemicals and
(ii) their proven usefulness in the oil exploration and production operations, the question arises of assessing the impact of SF6 and PFCs reservoir tracers on global warming and developing an alternative tracer technology that is substantially more environmentally friendly, AEOLOS objectives included:
– Specify sources of leakage and quantify emission levels of SF6 and PFCs during standard tracer reservoir technology programmes. These include leaks to the atmosphere directly at platforms during straight gas burning and hydrocarbon combustion at platforms and on-shore processing facilities and leaks during hydrocarbon transport and consequent consumption.
– Evaluate the effect of these emissions on global warming and atmospheric quality.
To ensure the smooth execution of the project the following main targets had to be achieved:
-Estimation of injected/released SF6 and PFCs amounts as reservoir tracers; Development of reliable database for sources distribution and rates of emissions.
– Qualitative and quantitative laboratory analysis of SF6 and PFCs combustion products under various realistic flame/temperature conditions.
– Field scale characterization of SF6, PFCs and their combustion products in relation to laboratory results.
– Assessment of the effect of SF6, PFCs tracers and combustion products on global warming and atmospheric quality.
The main results of the proposed project were the following:
– Specification of sources of leakage and quantification of emission levels of SF6 and PFCs during a standard tracer technology programme undertaken by the oil industry.
– Identification and quantification of combustion by-products of SF6 and PFCs at controlled conditions.
– Results from narrow-band and wide-band radiative transfer models on radiative forcing to evaluate the effect on global warming (climatic change) due to the estimated SF6 and PFCs emissions.
No earlier work had been conducted in this specific problem area. As a result, several aspects of the project took on an innovative character (identifying and mapping sources and rates of emissions of these gases, quantifying combustion by-products under various operating flame and temperature conditions). In addition, some of the results (mainly from the SF6/PFCs combustion studies) were generic in nature and had consequently important applications in other industrial sectors (aluminium production, HCFC-22 production, semiconductor manufacturing, electrical transmission and distribution, magnesium production and processing, soundproof glazing) that use these gases and should reduce their emissions asap. This aspect made the project of multi-sectorial importance and showed how its results and the associated benefits could diffuse to other industrial sectors.
1. Environmental Research Laboratory, NCSR ‘DEMOKRITOS’, Greece
2. Physics and Space Atmospheric Group, Physics Department, Imperial College Of Science, Technology And Medicine, UK
3. Institute For Energy Technology, IFE, Norway
4. MOL Hungarian Oil And Gas PLC, Hungary
5. State Pollution Control Authority, Norway
6. STATOIL ASA, Norway