The realities of storing carbon dioxide - A response to CO2 storage capacity issues raised by Ehlig-Economides & Economides

In a recent publication, Ehlig-Economides & Economides (2010) have sought to demonstrate that carbon dioxide capture and storage (CCS) is not technically or economically feasible, based on a supposed lack of underground storage capacity. We consider this to be a serious misrepresentation of the scientific, engineering and operational facts surrounding CCS. Ehlig-Economides & Economides raise a number of storage related issues: reservoir boundaries, capacity, pressure management, storage integrity, dissolution and storage in depleted reservoirs. We take each one in turn, highlighting specific errors in the paper but also drawing attention to more general background issues. Finally, we discuss in more detail some inconsistencies in the paper surrounding the reservoir engineering calculations

Managing CO2 storage resources in a mature CCS future

This paper summarises the potential for surface and subsurface interactions which might occur during CO2 storage operations. We discuss possible options for managing these interactions to provide timely storage capacity, illustrated with a regional case study from the Southern North Sea. The case study evaluates storage site options to provide storage capacity for CO2 supplied to the region until 205

Consensus Recommendations for the Use of Automated Insulin Delivery (AID) Technologies in Clinical Practice

International audienceThe significant and growing global prevalence of diabetes continues to challenge people with diabetes (PwD), healthcare providers and payers. While maintaining near-normal glucose levels has been shown to prevent or delay the progression of the long-term complications of diabetes, a significant proportion of PwD are not attaining their glycemic goals. During the past six years, we have seen tremendous advances in automated insulin delivery (AID) technologies. Numerous randomized controlled trials and real-world studies have shown that the use of AID systems is safe and effective in helping PwD achieve their long-term glycemic goals while reducing hypoglycemia risk. Thus, AID systems have recently become an integral part of diabetes management. However, recommendations for using AID systems in clinical settings have been lacking. Such guided recommendations are critical for AID success and acceptance. All clinicians working with PwD need to become familiar with the available systems in order to eliminate disparities in diabetes quality of care. This report provides much-needed guidance for clinicians who are interested in utilizing AIDs and presents a comprehensive listing of the evidence payers should consider when determining eligibility criteria for AID insurance coverage

Reservoir Fluid Monitoring in Carbon Dioxide Sequestration at Cranfield

AbstractCarbon dioxide (CO2) injection into the lower Tuscaloosa formation at Cranfield started in December 2009 and has been maintained at over one million tonnes per year. Two observation wells F2 and F3 are approximately two degrees down-dip of the injection well F1 at a distance of 68 m and 112 m, respectively. The top of the formation varies from 10,425’ (3178.45m) at the injector F1 to 10,434’ (3180.28m) at observation well F3. All wells are perforated below 10,450’ (3185.16) to the bottom of the lower Tuscaloosa formation.Temperature, pressure and density (T, P, and ρ respectively) of the fluid in F2 and F3 were measured several months after displacement of brine from the wells by the lighter phase flowing past the perforations at the bottom of the wells. The static temperature profiles in wells F2 and F3 are identical, and thus are an excellent proxy for the geothermal gradient at the site. Using a suitable equation of state, and the measured T, P and, fluid compositional profiles in F2 and F3 were inferred, assuming a binary mixture.The measured density profile in F1, confirmed by pressure derivative with respect to depth, was inconsistent with that of pure CO2 at the measured P and T. Contamination of CO2 with a lower density fluid was therefore hypothesized, with methane being a natural choice. With this assumption, the error between the measured and calculated densities was minimized to estimate the binary mixture composition using the GERG 2008 equation of state. The resultant amount of methane was found to be almost 8 mol%. Analysis of samples taken from surface supply pipeline of the injected gas validated this contamination estimate, which was due to the mixing of recycled CO2 from an enhanced oil recovery (EOR) site.The density profiles measured in observation wells F2 and F3 indicate a change in fluid composition with depth. An analysis similar to that conducted for F1 allowed us to calculate the mixture composition based on the measured density profile. The best fit curve indicates that F2 contained >18 mol% methane near the surface decreasing to significantly less than 18% at the well bottom. F3 contained approximately 8 mol% methane in the top 65% of the well with almost pure CO2 near the bottom.The observation that the fluid in F2 contains a higher fraction of methane than the injected stream can be explained by dissolution of CO2 and concomitant stripping of adsorbed and dissolved methane in the reservoir between F1 and the observation wells. Consequently, a methane-enriched fluid bank precedes the CO2-rich hyperbolic wave. The compositional variation of the CO2-rich fluid as a function of depth in the wellbore reflects the fluid compositional profile in the formation