Investigating Sequestration Potential of Carbonate Rocks during Tertiary Recovery from a Billion Barrel Oil Field , Weyburn , Saskatchewan : the Geoscience Framework ( IEA Weyburn CO 2 Monitoring and Storage Project )
Introduction In Western Canada the application of CO2 injection for enhanced, ‘tertiary’ oil recovery is a relatively recent addition to the arsenal available to reservoir engineers. The first successful application of CO2 as a miscible fluid in Western Canada began in 1984 at Joffre Field, a Cretaceous marine siliciclastic reservoir in southern Alberta. A significant portion of the remaining proven conventional oil reserves in Western Canada, however, reside in large mature Paleozoic carbonate fields, such as the Mississippian Weyburn Field in SE Saskatchewan (Figure 1). In combination with economically dictated tertiary recovery schemes, these large fields could provide attractive geologic sites for future sequestration of greenhouse gases. An immediate challenge to geoscientists is to assess the ability of these geologic containers to store CO2 for geologically significant lengths of time.
Interactions of CO2 with Formation Waters, Oil and Minerals and CO2 storage at the Weyburn IEA EOR site, Saskatchewan, Canada
Abstract The Weyburn oil field in Saskatchewan, Canada, is hosted in Mississippian carbonates and has been subject to injection of CO 2 since 2000. A detailed mineralogy study was completed as the basis for modeling of mineral storage of injected CO 2 . Combining the mineralogy with kinetic reaction path models and water chemistry allows estimates of mineral storage of CO 2 over 50 years of injection. These results, combined with estimates of pore volume, solubility of CO 2 in oil and saline formation waters, and the initial and final pore volume saturation with respect to oil, saline water and gas/supercritical fluid allow an estimate of CO 2 stored in saline water, oil and minerals over 50 years of CO 2 injection. Most injected CO 2 is stored in oil (6.5 × 10 6 –1.3 × 10 7  t), followed closely by storage in supercritical CO 2 (7.2 × 10 6  t) with saline formation water (1.5–2 × 10 6  t) and mineral storage (2–6 × 10 5  t) being the smallest sinks. If the mineral dawsonite forms, as modeling suggests, the majority of CO 2 dissolved in oil and saline formation water will be redistributed into minerals over a period of approximately 5000 years. The composition of produced fluids from a baseline sampling program, when compared to produced fluids taken three years after injection commenced, suggest that dawsonite is increasingly stable as pH decreases due to CO 2 injection. The results suggest that hydrocarbon reservoirs that contain low gravity oil and little or no initial gas saturation prior to CO 2 injection, may store the majority of injected CO 2 solubilized in oil, making such reservoirs the preferred targets for combined enhanced oil recovery-CO 2 storage projects.
Study on quantitative earthquake damage of Dujiangyan city, caused by 2008 MS=8.0 Wenchuan, China earthquake based on aerial imagery
The paper introduces quantitative earthquake damage estimation method based on remote sensing data. The quantitative remote sensing seismic damage index based on building damage extracted from the aerial image of Dujiangyan city proper, southwest China's Sichuan province, which acquired after 2008 Ms=8.0 Wenchuan earthquake. The actual seismic damage indices were determined by the ground-based investigation in the city proper. Then their quantitative relationship was established. The results indicate that it is possible to build quantitative model of remote sensing seismic damage, which will enhance significantly the practicality applying the remote sensing in emergency acquisition and analysis of seismic disaster.