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One unconfined compressive strength (UCS) test and four high-pressure triaxial stress tests were conducted on coal cores in order to best emulate the key issues regarding horizontal wellbore stability, coal strength, permeability change, and coal fines generation during the life cycle of a coalbed methane reservoir. The four non-trivial stress paths were: Loading Compression (LC), where the axial stress is increased while the confining stress is held constant; Loading Extension (LE), where the axial stress is held constant while the confining stress is increased; Unloading Compression (ULC), in which the axial stress is held constant while the confining stress is decreased; and Unloading Extension (ULE), during...
Permeability–porosity relationships for sediments from the northern Barbados, Costa Rica, Nankai, and Peru subduction zones were examined based on sediment type, grain size distribution, and general mechanical and chemical compaction history. Greater correlation was observed between permeability and porosity in siliciclastic sediments, diatom oozes, and nannofossil chalks than in nannofossil oozes. For siliciclastic sediments, grouping of sediments by percentage of clay-sized material yields relationships that are generally consistent with results from other marine settings and suggests decreasing permeability as percentage of clay-sized material increases. Correction of measured porosities for smectite content...
One unconfined compressive strength (UCS) test and four high-pressure triaxial stress tests were conducted on coal cores in order to best emulate the key issues regarding horizontal wellbore stability, coal strength, permeability change, and coal fines generation during the life cycle of a coalbed methane reservoir. The four non-trivial stress paths were: Loading Compression (LC), where the axial stress is increased while the confining stress is held constant; Loading Extension (LE), where the axial stress is held constant while the confining stress is increased; Unloading Compression (ULC), in which the axial stress is held constant while the confining stress is decreased; and Unloading Extension (ULE), during...
One unconfined compressive strength (UCS) test and four high-pressure triaxial stress tests were conducted on coal cores in order to best emulate the key issues regarding horizontal wellbore stability, coal strength, permeability change, and coal fines generation during the life cycle of a coalbed methane reservoir. The four non-trivial stress paths were: Loading Compression (LC), where the axial stress is increased while the confining stress is held constant; Loading Extension (LE), where the axial stress is held constant while the confining stress is increased; Unloading Compression (ULC), in which the axial stress is held constant while the confining stress is decreased; and Unloading Extension (ULE), during...
A cased and sealed borehole in the Northern Barbados accretionary complex was the site of the first attempts to measure permeability in situ along a plate boundary décollement. Three separate efforts at Hole 949C yielded permeability estimates for the décollement spanning four orders of magnitude. An analysis of problems encountered during installation of the casing and seals provides insights into how the borehole conditions may have led to the wide range of results. During the installation, sediments from the surrounding formation repeatedly intruded into the borehole and casing. Stress analysis shows that the weak sediments were deforming plastically and the radial and tangential stresses around the borehole...
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Conclusions: Grizzly bears avoid high volume roads (25,000 vehicles/day). High quality habitat determines movement decisions relative to roads. Grizzly bears will cross high volume roads to access high-quality habitat. Grizzly bears use areas close to roads more than expected, in particular low-volume roads (10,000 vehicles/day). Prevent loss of habitat connectivity with the following mitigation: maintain high-quality habitat adjacent to roads, install continuous highway fencing and create wildlife passages. Thresholds/Learnings: Synopsis: The study examined the relationships among grizzly bears, their habitats and roads in Banff National Park, a protected area characterized by a major transportation corridor. This...
One unconfined compressive strength (UCS) test and four high-pressure triaxial stress tests were conducted on coal cores in order to best emulate the key issues regarding horizontal wellbore stability, coal strength, permeability change, and coal fines generation during the life cycle of a coalbed methane reservoir. The four non-trivial stress paths were: Loading Compression (LC), where the axial stress is increased while the confining stress is held constant; Loading Extension (LE), where the axial stress is held constant while the confining stress is increased; Unloading Compression (ULC), in which the axial stress is held constant while the confining stress is decreased; and Unloading Extension (ULE), during...
Permeability–porosity relationships for sediments from the northern Barbados, Costa Rica, Nankai, and Peru subduction zones were examined based on sediment type, grain size distribution, and general mechanical and chemical compaction history. Greater correlation was observed between permeability and porosity in siliciclastic sediments, diatom oozes, and nannofossil chalks than in nannofossil oozes. For siliciclastic sediments, grouping of sediments by percentage of clay-sized material yields relationships that are generally consistent with results from other marine settings and suggests decreasing permeability as percentage of clay-sized material increases. Correction of measured porosities for smectite content...
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Conclusions: Emigration rates are closely tied to edge structure. Low contrast edges promote edge permeability Thresholds/Learnings: Synopsis: The behavior of two butterfly species, one habitat specialist and one habitat generalist, were tracked at four prairie edges to determine the extent to which edge structure affects emigration. The specialist species responded strongly to all edges, and was particularly affected by edge density. The generalist species responded strongly only to high contrast edges. Emigration rates are closely tied to edge structure. Therefore, promoting low contrast edges in conservation planning may positively influence edge permeability and species richness in highly fragmented landscapes.
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We have defined resilience as a function of both a site’s diversity of topoclimates and the site’s ability to support species movement, or terrestrial landscape permeability. Here, we posit that topoclimates provide species localized refugia from the direct effects of a changing climate, whereas landscape permeability reflects the ability of the landscape mosaic to facilitate terrestrial species movement to and between topoclimates as they shift in response to their respective climatic envelopes.90 m topoclimate data, scaled from 0.2 – 1, were multiplied with terrestrial landscape permeability data, scaled from 0 – 1, to generate a resilience value for every 90 m cell across the project area. A full description...
Geofluids (2010) 10, 193–205AbstractThe variation of permeability with depth can be probed indirectly by various means, including hydrologic models that use geothermal data as constraints and the progress of metamorphic reactions driven by fluid flow. Geothermal and metamorphic data combine to indicate that mean permeability (k) of tectonically active continental crust decreases with depth (z) according to log k ≈ −14–3.2 log z, where k is in m2 and z in km. Other independently derived, crustal-scale k–z relations are generally similar to this power-law curve. Yet there is also substantial evidence for local-to-regional-scale, transient, permeability-generation events that entail permeabilities much higher than...
Triggering of seismicity by pore-pressure perturbations: Permeability-related signatures of the phenomenon, credited to Shapiro, SA, published in 2003. Published in Pure and applied …, volume 160, on pages 1051 - 1066, in 2003.
This report describes an effort of a team of 60 scientists led by The Nature Conservancy (TNC) to identify the places where nature’s own natural resilience is the highest. Thanks to the land’s diverse topography, bedrock, and soil, these climate-resilient sites are more likely to sustain native plants, animals, and natural processes into the future, becoming natural strongholds for diversity. To map their locations, The Nature Conservancy-led team used over 70 new and comprehensive datasets to find places that are buffered from the effects of climate change because the site offers a wide range of micro-climates within a highly connected area. In 2015, the results were published in a leading conservation science...
    map background search result map search result map Butterfly responses to habitat edges in highly fragmented prairies of central Iowa. Relationships among grizzly bears, highways, and habitat in Banff-Bow Valley, Alberta, Canada. Terrestrial Landscape Resilience to Climate Change (90 m) Relationships among grizzly bears, highways, and habitat in Banff-Bow Valley, Alberta, Canada. Butterfly responses to habitat edges in highly fragmented prairies of central Iowa. Terrestrial Landscape Resilience to Climate Change (90 m)