Characterizing small-scale migration behavior of sequestered CO2 in a realistic geological fabric

For typical reservoir conditions, buoyancy and capillary forces grow dominant over viscous forces within a few hundred meters of the injection wells as the pressure gradient due to injection decreases, resulting in qualitatively different plume migration regimes. The migration regime depends on two factors: the capillary pressure of the leading edge of the plume and the range of threshold entry pressures within the rock at the leading edge of the plume. A capillary channel regime arises when these two factors have the same magnitude. Flow patterns within this regime vary from finger-like structures with minimal rock contact to back-filling structures with compact volumes of saturation distributed between fingers. Reservoir heterogeneity is one of the principal factors influencing CO2 migration pathway in the capillary channel regime. Here we characterize buoyancy-driven migration in a natural 2D geologic domain (1 m × 0.5 m peel from an alluvium) in which sedimentologic heterogeneity has been resolved at sub-millimeter (depositional) resolution. The relevant features of the heterogeneity are grain size distribution, which determines the mean and range of threshold pressures and correlation lengths of threshold pressures in horizontal and vertical directions. The relevant physics for this migration regime is invasion percolation, and simulations indicate that CO2 migrates through the peel in a few narrow pathways which cannot be captured by conventional coarse-grid simulations. The storage efficiency of the capillary channel regime would be low and consequently CO2 would also migrate greater distances than expected from models or simulations that neglect the capillary channel flow regime.Bureau of Economic Geolog

An atlas of CO2 storage potential in the nearshore waters of the Texas coast – American Recovery and Reinvestment Act – “Gulf of Mexico Miocene CO2 site characterization mega-transect”

Bureau of Economic Geolog

Continuous pressure monitoring for large volume CO2 injections

Elevated formation fluid pressure resulting from large-volume injection of carbon dioxide (CO2) for sequestration is a key factor affecting storage seal integrity (containment risk) and ultimate capacity. Current methods for predicting pressure evolution (e.g. natural gas storage, EOR, groundwater withdrawal/recharge) have unique considerations (temporal cyclicity, associated production) and have only recently been applied for the injected volumes, durations, and extents of sequestration projects. Monitoring pressure dynamics (buildup during injection and subsequent falloff upon cessation) is a fundamental and relatively inexpensive technique for monitoring storage performance. Our research employs multiple numerical techniques to predict the evolution of pressure within reservoirs and to evaluate the potential impact on confining systems (seals), thus constraining site-specific sequestration storage integrity and capacity. We focus on the use of pressure measurements for pragmatic integrative monitoring of reservoir, seal, and well performance. The results presented here focus on real-time pressure and temperature evolution in a dedicated observation well, combining observations from both the injection interval and a monitoring interval 120 m higher for early detection of unanticipated migration out of the injection zone via wellbores or confining system. Results indicate that for the Cranfield reservoir, increases (and by inference, decreases corresponding to pressure loss due to out of zone migration) in injection rates of 100’s of tons per day are observable from less than a kilometer distance from the source.Bureau of Economic Geolog

Current subsidence rates due to compaction of Holocene sediments in southern Louisiana

This paper is not subject to U.S. copyright. The definitive version was published in Geophysical Research Letters 33 (2006): L11403, doi:10.1029/2006GL026300.Relative contributions of geologic and anthropogenic processes to subsidence of southern Louisiana are vigorously debated. Of these, shallow sediment compaction is often considered dominant, although this has never been directly observed or effectively demonstrated. Quantitative understanding of subsidence is important for predicting relative sea level rise, storm surge flooding due to hurricanes, and for successful wetland restoration. Despite many shallow borings, few appropriate stratigraphic and geotechnical data are available for site-specific calculations. We overcome this by determining present compaction rates from Monte Carlo simulations of the incremental sedimentation and compaction of stratigraphies typical of the Holocene of southern Louisiana. This approach generates distributions of present compaction rates that are not expected to exceed 5 mm/yr, but may locally. Locations with present subsidence rates greater than the predicted maximum probable shallow compaction rates are likely influenced by additional processes

Development of a prototype fluid volume measurement system

The research is reported in applying the axial fluid temperature differential flowmeter to a urine volume measurement system for space missions. The fluid volume measurement system is described along with the prototype equipment package. Flowmeter calibration, electronic signal processing, and typical void volume measurements are also described

Multiorbital tunneling ionization of the CO molecule

We coincidently measure the molecular frame photoelectron angular distribution and the ion sum-momentum distribution of single and double ionization of CO molecules by using circularly and elliptically polarized femtosecond laser pulses, respectively. The orientation dependent ionization rates for various kinetic energy releases allow us to individually identify the ionizations of multiple orbitals, ranging from the highest occupied to the next two lower-lying molecular orbitals for various channels observed in our experiments. Not only the emission of a single electron, but also the sequential tunneling dynamics of two electrons from multiple orbitals are traced step by step. Our results confirm that the shape of the ionizing orbitals determine the strong laser field tunneling ionization in the CO molecule, whereas the linear Stark effect plays a minor role.Comment: This paper has been accepted for publication by Physical Review Letter

Potential sinks for geologic storage of carbon dioxide generated by power plants in North and South Carolina

Duke Energy Progress Energy Santee Cooper Power SCANA CorporationBureau of Economic Geolog