67 research outputs found
The Possibility of Extending the Detection Function of an Analytical System to Lower Concentrations
It is shown that the only way to increase the detection capacity
of an analytical system is based on the use of the multitude
values of the single analytical signal. This can be achieved in two
modalities: 1) fixed multitude values (as mean or as sum), and 2)
sequential multitude values (as signal sum and as frequencies sum).
By using these procedures, the analytical detection can be applied
under the classical detection limit at as low concentrations as
desired, provided that the multitude of the individual values of the
signal be sufficiently high
The Geomechanics of CO2 Storage in Deep Sedimentary Formations
This paper provides a review of the geomechanics and modeling of geomechanics associated with geologic carbon storage (GCS), focusing on storage in deep sedimentary formations, in particular saline aquifers. The paper first introduces the concept of storage in deep sedimentary formations, the geomechanical processes and issues related with such an operation, and the relevant geomechanical modeling tools. This is followed by a more detailed review of geomechanical aspects, including reservoir stress-strain and microseismicity, well integrity, caprock sealing performance, and the potential for fault reactivation and notable (felt) seismic events. Geomechanical observations at current GCS field deployments, mainly at the In Salah CO2 storage project in Algeria, are also integrated into the review. The In Salah project, with its injection into a relatively thin, low-permeability sandstone is an excellent analogue to the saline aquifers that might be used for large scale GCS in parts of Northwest Europe, the U.S. Midwest, and China. Some of the lessons learned at In Salah related to geomechanics are discussed, including how monitoring of geomechanical responses is used for detecting subsurface geomechanical changes and tracking fluid movements, and how such monitoring and geomechanical analyses have led to preventative changes in the injection parameters. Recently, the importance of geomechanics has become more widely recognized among GCS stakeholders, especially with respect to the potential for triggering notable (felt) seismic events and how such events could impact the long-term integrity of a CO{sub 2} repository (as well as how it could impact the public perception of GCS). As described in the paper, to date, no notable seismic event has been reported from any of the current CO{sub 2} storage projects, although some unfelt microseismic activities have been detected by geophones. However, potential future commercial GCS operations from large power plants will require injection at a much larger scale. For such largescale injections, a staged, learn-as-you-go approach is recommended, involving a gradual increase of injection rates combined with continuous monitoring of geomechanical changes, as well as siting beneath a multiple layered overburden for multiple flow barrier protection, should an unexpected deep fault reactivation occur
Titrimetric applications of multiparametric curve-fitting. Locations of end points in amperometric, conductometric, spectrophotometric, and similar titrations
Polyphosphate currents at the lead dioxide electrode for hydrolysis rate and instability constant measurements
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