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Laura Chiaramonte Mark D. Zoback Julio Friedmann Vicki Stamp 《Environmental Geology》2008,54(8):1667-1675
This paper reports a preliminary investigation of CO2 sequestration and seal integrity at Teapot Dome oil field, Wyoming, USA, with the objective of predicting the potential risk
of CO2 leakage along reservoir-bounding faults. CO2 injection into reservoirs creates anomalously high pore pressure at the top of the reservoir that could potentially hydraulically
fracture the caprock or trigger slip on reservoir-bounding faults. The Tensleep Formation, a Pennsylvanian age eolian sandstone
is evaluated as the target horizon for a pilot CO2 EOR-carbon storage experiment, in a three-way closure trap against a bounding fault, termed the S1 fault. A preliminary geomechanical
model of the Tensleep Formation has been developed to evaluate the potential for CO2 injection inducing slip on the S1 fault and thus threatening seal integrity. Uncertainties in the stress tensor and fault
geometry have been incorporated into the analysis using Monte Carlo simulation. The authors find that even the most pessimistic
risk scenario would require ∼10 MPa of excess pressure to cause the S1 fault to reactivate and provide a potential leakage
pathway. This would correspond to a CO2 column height of ∼1,500 m, whereas the structural closure of the Tensleep Formation in the pilot injection area does not exceed
100 m. It is therefore apparent that CO2 injection is not likely to compromise the S1 fault stability. Better constraint of the least principal stress is needed to
establish a more reliable estimate of the maximum reservoir pressure required to hydrofracture the caprock. 相似文献
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M. A. F. M. Rashidul Hasan M. M. Keramat S. Shahid R. Yasmin M. Mohsenipour Golam Shabbir Sattar 《Geotechnical and Geological Engineering》2016,34(5):1395-1411
Barind Tract, located north western part of Bangladesh, is one of the most diversified physiographic units of the country. The surface water supply in this part is particularly limited, so the irrigation is almost entirely depends on groundwater. However, over exploitation indicates falling groundwater heads in this area. The objective of present study is to examine the nature of the aquifer system Barind Tract of Bangladesh in order to assess the sustainability of groundwater yield. Borehole lithology data were collected, processed and analyzed for this purpose. Representative panel diagram, 3-D stratigraphic and cross-sectional views were also prepared for necessary assessment of the variation of individual subsurface stratum in different locations. The study identified three subsurface geologic formations namely, a top clay layer, sand layer of different grain size and at the bottom an impermeable clay zone. Maps of formation thickness and index revealed that aquifer thickness is low in the north-western corner and in some places of middle of south-western corner. The thickness of sand formation in other places is recorded above 20 m. It is expect that the finding of the study will help groundwater resources development, planning and management in the area. 相似文献
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Two end-members characterize a continuum of continental extensional tectonism: rift settings and highly extended terrains. These different styles result in and are recorded by different extensional basins. Intracontinental rifts (e.g. East Africa, Lake Baikal) usually occur in thermally equilibrated crust of normal thickness. Rift settings commonly display alkali to tholeiitic magmatism, steeply dipping (45–60°) bounding faults, slip rates <1 mm yr-1 and low-magnitude extension (10–25%). Total extension typically requires > 25 Myr. The fault and sub-basin geometry which dominates depositional style is a half-graben bounded by a steeply dipping normal fault. Associated basins are deep (6–10 km), and sedimentation is predominantly axial- or hangingwall-derived. Asymmetric subsidence localizes depocentres along the active basin-bounding scarp. Highly extended continental terrains (e.g. Colorado River extensional corridor, the Cyclade Islands) represent a different tectonic end-member. They form in back-arc regions where the crust has undergone dramatic thickening before extension, and usually reactivate recently deformed crust. Volcanism is typically calc-alkalic, and 80–90% of total extension requires much less time (<10 Myr). Bounding faults are commonly active at shallow dips (15–35°); slip rates (commonly > 2 mm yr-1) and bulk extension (often > 100%) are high. The differences in extension magnitude and rate, volcanism, heat flow, and structural style suggest basin evolution will differ with tectonic setting. Supradetachment basins, or basins formed in highly extended terrains, have predominantly long, transverse drainage networks derived from the breakaway footwall. Depocentres are distal (10–20 km) to the main bounding fault. Basin fill is relatively thin (typically 1–3 km), probably due to rapid uplift of the tectonically and erosionally denuded footwall. Sedimentation rates are high (? 1 m kyr-1) and interrupted by substantial unconformities. In arid and semi-arid regions, fluvial systems are poorly developed and alluvial fans dominated by mass-wasting (debris-flow, rock-avalanche breccias, glide blocks) represent a significant proportion (30–50%) of basin fill. The key parameters for comparing supradetachment to rift systems are extension rate and amount, which are functions of other factors like crustal thickness, thermal state of the lithosphere and tectonic environment. Changes in these parameters over time appear to result in changes to basin systematics. 相似文献
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H. Friedmann 《Pure and Applied Geophysics》1984,122(2-4):531-544
A model for radon anomalies before earthquakes, with a relatively fast increase in radon concentration at the beginning of the anomaly, is postulated. A calculation based on this model shows that a parameter can be deduced from the form of the radon anomalies, which depends on the epicentral distance of the measurement point. After adjustment of some parameters the model calculation is in good agreement with observed earthquake precursor anomalies. 相似文献
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Laboratory experiments show that undercooling to about -5 degrees C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5 degrees C and -5 degrees C or -10 degrees C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid cooling to -50 degrees C. 14CO2 incorporation after freezing to -20 degrees C was unaffected in H. antarctica or in Trebouxia sp. but slightly depressed in Stichococcus sp. (isolated from a less extreme Antarctic habitat). These results suggest that the freezing regime in the Antarctic desert is not injurious to endolithic algae. It is likely that the freezing-point depression inside the rock makes available liquid water for metabolic activity at subzero temperatures. Freezing may occur more frequently on the rock surface and contribute to the abiotic nature of the surface. 相似文献
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The existence of microbial communities living inside desert rocks has been reported by FRIEDMANN et al. (1967, 1976), first in rocks collected from the hot and dry Negev desert and later in rocks in the frigid Ross Desert of Southern Victoria Land, Antarctica. The extremely inhospitable climatic conditions in both places has led to the suggestion that these organisms have very low rates of metabolism and may, in addition, be very old (FRIEDMANN 1982). Our preliminary measurements showed a 14C deficiency indicating a carbon age in the order of magnitude of 10(3) years. 相似文献
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Cryptoendolithic microbial communities in the Ross Desert (McMurdo Dry Valleys) are characterized on the basis of photosynthetic microorganisms and fungi. Two eukaryotic communities (the lichen-dominated and Hemichloris communities) and three cyanobacterial communities (the red Gloeocapsa, Hormathonema-Gloeocapsa, and Chroococcidiopsis communities) are described. Eleven coccoid, one pleurocapsoid, and five filamentous cyanobacteria occurring in these communities are characterized and illustrated. The moisture grade of the rock substrate seems to affect pH, formation of primary iron stain, and the distribution of microbial communities. 相似文献
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S. Julio Friedmann N. Taberlet W. Losert 《International Journal of Earth Sciences》2006,95(5):911-919
Rock avalanches are known to behave in extraordinary ways unlike other landslides, and their deposits in part reflect their unusual physical behavior. Recent experiments in granular physics suggest that many phenomena and features simply reflect the non-linear nature of granular flows, although some behavior cannot simply be reproduced in lab scale experiments. In a static configuration, grain–grain contact networks dominate the distribution of forces and stresses within a granular mass. During flow, granular collisions damp the system through energy dissipation, while gravitational potential drives the system. The energy distribution between static and collisional stresses within the system can change very rapidly. Threshold events dominate system response, and the challenge is to find which characterization of the static phase helps to predict failure (and thus flow) resistance. Once flowing, many “unusual” rock-avalanche phenomena are entirely consistent with the physics of flow of large granular masses, but the low energy dissipation rate required for long run-out events requires the presence of physical processes that are not involved in experimental flows in the current parameter range or in the assumptions of current models. 相似文献