scholarly journals Inelastic compaction and permeability evolution in volcanic rock

2016 ◽  
Author(s):  
Jamie I. Farquharson ◽  
Patrick Baud ◽  
Michael J. Heap
Keyword(s):  
Volcanic Rock ◽  
Confining Pressure ◽  
Permeability Evolution ◽  
Physical Limit ◽  
In Situ Conditions ◽  
Wide Range ◽  
Porosity And Permeability ◽  
Progressive Strain ◽  
Active Volcanoes

Abstract. Active volcanoes are mechanically dynamic environments, and edifice-forming material may often be subjected to significant amounts of stress and strain. It is understood that porous volcanic rock can compact inelastically under a wide range of in situ conditions. In this contribution, we explore the evolution of porosity and permeability – critical properties influencing the style and magnitude of volcanic activity – as a function of inelastic compaction of porous andesite under triaxial conditions. Progressive strain accumulation is associated with progressive porosity loss. The efficiency of compaction was found to be related to the effective confining pressure under which deformation occurred: at higher effective pressure, more porosity was lost for any given amount of strain. Permeability evolution is more complex, with small amounts of stress-induced compaction ( 0.20) where samples may undergo a reduction in permeability by two orders of magnitude relative to their initial values. A physical limit to compaction is discussed, which we suggest is echoed in a limit to the potential for permeability reduction in compacting volcanic rock. Compiled literature data illustrate that at high strain (both in the brittle and ductile regimes), porosity ϕ and permeability k tend to converge towards intermediate values (i.e. 0.10 ≤ ϕ ≤ 0.20; 10–14 ≤ k ≤10–13 m2). These results are discussed in light of their potential ramifications for impacting edifice outgassing – and in turn, eruptive activity – at active volcanoes.

scholarly journals Inelastic compaction and permeability evolution in volcanic rock

Solid Earth ◽  
2017 ◽  
Vol 8 (2) ◽  
pp. 561-581 ◽  
Author(s):  
Jamie I. Farquharson ◽  
Patrick Baud ◽  
Michael J. Heap
Keyword(s):  
Volcanic Rock ◽  
Axial Strain ◽  
Inelastic Strain ◽  
Confining Pressure ◽  
Sample Length ◽  
Strain Accumulation ◽  
Permeability Evolution ◽  
In Situ Conditions ◽  
Wide Range ◽  
Active Volcanoes

Abstract. Active volcanoes are mechanically dynamic environments, and edifice-forming material may often be subjected to significant amounts of stress and strain. It is understood that porous volcanic rock can compact inelastically under a wide range of in situ conditions. In this contribution, we explore the evolution of porosity and permeability – critical properties influencing the style and magnitude of volcanic activity – as a function of inelastic compaction of porous andesite under triaxial conditions. Progressive axial strain accumulation is associated with progressive porosity loss. The efficiency of compaction was found to be related to the effective confining pressure under which deformation occurred: at higher effective pressure, more porosity was lost for any given amount of axial strain. Permeability evolution is more complex, with small amounts of stress-induced compaction ( <  0.05, i.e. less than 5 % reduction in sample length) yielding an increase in permeability under all effective pressures tested, occasionally by almost 1 order of magnitude. This phenomenon is considered here to be the result of improved connectivity of formerly isolated porosity during triaxial loading. This effect is then overshadowed by a decrease in permeability with further inelastic strain accumulation, especially notable at high axial strains ( >  0.20) where samples may undergo a reduction in permeability by 2 orders of magnitude relative to their initial values. A physical limit to compaction is discussed, which we suggest is echoed in a limit to the potential for permeability reduction in compacting volcanic rock. Compiled literature data illustrate that at high axial strain (both in the brittle and ductile regimes), porosity ϕ and permeability k tend to converge towards intermediate values (i.e. 0.10  ≤ ϕ ≤  0.20; 10−14 ≤ k ≤ 10−13 m2). These results are discussed in light of their potential ramifications for impacting edifice outgassing – and in turn, eruptive activity – in active volcanoes.

scholarly journals Induced microearthquakes predict permeability creation in the brittle crust

2022 ◽  
Author(s):  
Ziyan Li ◽  
Derek Elsworth ◽  
Chaoyi Wang
Keyword(s):  
Patch Size ◽  
Dynamic Evolution ◽  
Permeability Evolution ◽  
Field Scale ◽  
Scale Invariant ◽  
Flow Paths ◽  
Porosity And Permeability ◽  
Hybrid Machine ◽  
Early Injection

Abstract Fracturing controls rates of mass, chemical and energy cycling within the crust. We use observed locations and magnitudes of microearthquakes (MEQs) to illuminate the evolving architecture of fractures reactivated and created in the otherwise opaque subsurface. We quantitatively link seismic moments of laboratory MEQs to the creation of porosity and permeability at field scale. MEQ magnitudes scale to the slipping patch size of remanent fractures reactivated in shear - with scale-invariant roughnesses defining permeability evolution across nine decades of spatial volumes – from centimeter to decameter scale. This physics-inspired seismicity-permeability linkage enables hybrid machine learning (ML) to constrain in-situ permeability evolution at verifiable field-scales (~10 m). The ML model is trained on early injection and MEQ data to predict the dynamic evolution of permeability from MEQ magnitudes and locations, alone. The resulting permeability maps define and quantify flow paths verified against ground truths of permeability.

scholarly journals Temperature response of denitrification and anammox reveals the adaptation of microbial communities to in situ temperatures in permeable marine sediments that span 50° in latitude

2013 ◽  
Vol 10 (9) ◽  
pp. 14595-14626 ◽  
Author(s):  
A. Canion ◽  
J. E. Kostka ◽  
T. M. Gihring ◽  
M. Huettel ◽  
J. E. E. van Beusekom ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Marine Sediments ◽  
Metabolic Response ◽  
Anammox Bacteria ◽  
Advective Flow ◽  
Permeable Sediments ◽  
N Removal ◽  
In Situ Conditions ◽  
Wide Range

Abstract. Despite decades of research on the physiology and biochemistry of nitrate/nitrite-respiring microorganisms, little is known regarding their metabolic response to temperature, especially under in situ conditions. The temperature regulation of microbial communities that mediate anammox and denitrification was investigated in near shore permeable sediments at polar, temperate, and subtropical sites with annual mean temperatures ranging from −5 to 23 °C. Total N2 production rates were determined using the isotope pairing technique in intact core incubations under diffusive and simulated advection conditions and ranged from 2 to 359 μmol N m−2 d−1. For the majority of sites studied, N2 removal was 2 to 7 times more rapid under advective flow conditions. Anammox comprised 6 to 14% of total N2 production at temperate and polar sites and was not detected at the subtropical site. Potential rates of denitrification and anammox were determined in anaerobic slurries in a temperature gradient block incubator across a temperature range of −1 to 42 °C. The highest optimum temperature (Topt) for denitrification was 36 °C and was observed in subtropical sediments, while the lowest Topt of 21 °C was observed at the polar site. Seasonal variation in the Topt was observed at the temperate site with values of 26 and 34 °C in winter and summer, respectively. The Topt values for anammox were 9 and 26 °C at the polar and temperate sites, respectively. The results demonstrate adaptation of denitrifying communities to in situ temperatures in permeable marine sediments across a wide range of temperatures, whereas marine anammox bacteria may be predominately psychrophilic to psychrotolerant. To our knowledge, we provide the first rates of denitrification and anammox from permeable sediments of a polar permanently cold ecosystem. The adaptation of microbial communities to in situ temperatures suggests that the relationship between temperature and rates of N removal is highly dependent on community structure.

scholarly journals Effect of Stress and Moisture Content on Permeability of Gas-Saturated Raw Coal

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Junhui Wang ◽  
Zhijun Wan ◽  
Yi Wang ◽  
Zhixiang Liu ◽  
Sifei Liu ◽  
...  
Keyword(s):  
Moisture Content ◽  
Coalbed Methane ◽  
Confining Pressure ◽  
Porous Matrix ◽  
In Situ Stress ◽  
Permeability Evolution ◽  
Test Range ◽  
Moisture Contents ◽  
Volumetric Stress

Hydraulic fracturing and premining gas drainage are important to safe mining and coalbed methane extraction. These technical processes cause the redistribution of in-situ stress and the regional variation of moisture contents within the affected zone. Therefore, we investigated the coupled effect of variable stresses (from 9 MPa to 27 MPa) and moisture contents (from 0.22% to 4.00%) on the permeability evolution of gas-saturated raw coal. The results show that (1) the relationship between the mean effective stress and the permeability can be described by a power function according to the permeability evolution model of the porous matrix established in this study. Besides, the influence mechanisms of moisture on fitting coefficients in the function were analyzed. (2) The permeability decreases with the increase of in-situ stress (e.g., confining pressure or volumetric stress) in a negative exponential manner. (3) The curves of permeability variations with moisture content are not always linear, and the permeability is more sensitive to the moisture content than the volumetric stress in the test range. Moreover, the sensitivity of permeability varies in different regions. These results would be beneficial for permeability prediction and surface well parameters design.

Microwave properties of drilling fluids

Geophysics ◽  
1981 ◽  
Vol 46 (3) ◽  
pp. 322-332 ◽  
Author(s):  
James N. Lange ◽  
Steven S. Shope
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Weight Percent ◽  
Dielectric Constants ◽  
Drilling Fluids ◽  
Nanosecond Pulses ◽  
Microwave Attenuation ◽  
In Situ Conditions ◽  
Wide Range

The application of electromagnetic (EM) techniques to well logging is initiated in an environment dominated by the properties of the drilling fluids. An impulse technique using nanosecond pulses is applied to a coaxial waveguide containing drilling fluids to measure the velocity (dielectric constant ε) and absorption (attenuation coefficient α) of EM impulses. It is the large difference in dielectric constants of water and oil which makes EM propagation techniques attractive for logging. Dielectric properties of some nondispersed drilling fluids (bentonite and attapulgite clays) are found to be largely dependent upon the volume of water present. Both bentonite and attapulgite clays exhibit the same range of dielectric constants (ε = 81 → 75) when the weight percent of clay is increased to 10 percent. In contrast, the microwave attenuations of these two clays are quite different, with that of the bentonite increasing at about 4 times the rate of the attapulgite suspensions. Microwave attenuation measured for a variety of commercial drilling fluids varies over a wide range, with the lignosulfonates the largest (91 dB/m) and oil inverts the smallest (3 dB/m). The oil inverts also have a small dielectric constant (ε = 3 → 6). Temperature dependence of the attenuation for these same drilling fluids is determined in the range from 23 °C to 45 °C to indicate their behavior under in situ conditions.

scholarly journals Volumetric behavior of natural swelling soil on drying-wetting paths. Application to the Boumagueur marl -Algeria-

2020 ◽  
Vol 42 (3) ◽  
pp. 248-262
Author(s):  
Mehdi Mebarki ◽  
Toufik Kareche ◽  
Sabah Benyahia ◽  
Feth-Ellah Mounir Derfouf ◽  
Nabil Abou-Bekr ◽  
...  
Keyword(s):  
Clayey Soil ◽  
Degree Of Saturation ◽  
Undisturbed Soil ◽  
Pressuremeter Test ◽  
Swelling Soil ◽  
In Situ Conditions ◽  
Wide Range ◽  
Eastern Algeria ◽  
Volumetric Behavior

AbstractThis article presents the results of experimental work carried out both in situ (coring; pressuremeter test) and in the laboratory (drying-wetting and oedometric tests) to describe the volumetric behavior on drying-wetting path of a swelling clayey soil of eastern Algeria. In order to perform drying-wetting tests the osmotic technique and saturated salts solutions were used. These suction-imposed methods have gained widespread acceptance as reliable methods for imposing suction on soil specimens. They allowed to sweep a wide range of suctions between 0 and 500 MPa. The ability to impose suction on soil specimens allows for drying and wetting stress paths to be applied to evaluate resulting changes in state parameters (void ratio, degree of saturation and water content). These paths were carried out on specimens with different initial states. Slurries of soil were used to characterize the reference behavior, while the undisturbed soil samples allow to describe the behavior of material under in situ conditions. In the last part of this article and to specify the behavior observed in the saturated domain, a comparison between the resulting deformations of the drying-wetting test and those resulting from the oedometric test was made.

scholarly journals The analysis on the correlation parameters of the embankment compaction under in situ conditions

2013 ◽  
Vol 12 (3) ◽  
pp. 097-104
Author(s):  
Maciej Kumor ◽  
Łukasz Kumor ◽  
Joanna Farmas
Keyword(s):  
Particle Size ◽  
In Situ Tests ◽  
Geotechnical Assessment ◽  
In Situ Conditions ◽  
Wide Range ◽  
Correlation Parameters ◽  
And Control

Geotechnical assessment of the implementation correctness of a road embankment wide range of issues, among which important selection and control of the quality of the earthworks are extremely significant. The article presents results of in situ tests determining correlations between the depending parameters defined by a static plate – VSS test – E1 and E2, and obtained from the study LFG Dynamic Load Plate. Studies indicate that the determination of the correlation between the parameters characterizing the particle size distribution (Cc, Cu, D10, D20, D30, D60), and the compaction parameters obtained by examining the compaction of sand embankment (Evd, E1, E2, I0) is physically complex and hence extremely difficult. 

scholarly journals Innovative Apparatus for Testing Filtration, Sorption and CO2/CH4 Exchange Sorption Processes Under Isobaric Conditions on Sorbent Subjected to Confining Pressure in Terms of Laboratory Tests of CO2-ECBM Technology

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5823
Author(s):  
Mateusz Kudasik ◽  
Norbert Skoczylas ◽  
Anna Pajdak
Keyword(s):  
Confining Pressure ◽  
Sample Volume ◽  
Injection System ◽  
Coal Bed ◽  
Methane Recovery ◽  
Pressure System ◽  
Correct Operation ◽  
System A ◽  
In Situ Conditions

In recent years, the interest in the sorption properties of coal in conditions corresponding to in situ has increased due to the continuous development of research on CO2-ECBM (Enhanced Coal Bed Methane recovery) technology. In order to gain a better insight into a number of phenomena related to filtration, sorption and CO2/CH4 exchange sorption occurring in coal loaded with confining pressure, which corresponds to the in situ conditions, an innovative research apparatus was built to enable temporal and spatial analysis of these phenomena. The constructed apparatus consists of three systems: a high-pressure system, a gas injection system and a gas emission system. The work presents the results of basic apparatus tests, which were aimed at checking its correct operation and determining its specifications. These tests involved carrying out trial measurements of methane (CH4) filtration processes, CH4 sorption and CO2/CH4 exchange sorption on a coal sample. The results of the tests showed among other things that the apparatus ensured the regulation of the confining pressure in the range of 0.1–40 MPa, the regulation of the pressure at the inlet and outlet of the sample in the range of 0.1–1.6 MPa and 0.1–1.0 MPa and the measurement of changes in the sample volume in the range of 0–7.85 cm3. The results of the tests confirmed the correct functioning of the constructed apparatus.

scholarly journals Temperature response of denitrification and anammox reveals the adaptation of microbial communities to in situ temperatures in permeable marine sediments that span 50° in latitude

2014 ◽  
Vol 11 (2) ◽  
pp. 309-320 ◽  
Author(s):  
A. Canion ◽  
J. E. Kostka ◽  
T. M. Gihring ◽  
M. Huettel ◽  
J. E. E. van Beusekom ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Marine Sediments ◽  
Metabolic Response ◽  
Temperature Response ◽  
Anammox Bacteria ◽  
Advective Flow ◽  
N Removal ◽  
In Situ Conditions ◽  
Wide Range

Abstract. Despite decades of research on the physiology and biochemistry of nitrate/nitrite-respiring microorganisms, little is known regarding their metabolic response to temperature, especially under in situ conditions. The temperature regulation of microbial communities that mediate anammox and denitrification was investigated in near shore permeable sediments at polar, temperate, and subtropical sites with annual mean temperatures ranging from −5 to 23 °C. Total N2 production rates were determined using the isotope pairing technique in intact core incubations under diffusive and simulated advection conditions and ranged from 2 to 359 μmol N m−2 d−1. For the majority of sites studied, N2 removal was 2–7 times more rapid under simulated advective flow conditions. Anammox comprised 6–14% of total N2 production at temperate and polar sites and was not detected at the subtropical site. Potential rates of denitrification and anammox were determined in anaerobic slurries in a temperature gradient block incubator across a temperature range of −1 °C to 42 °C. The highest optimum temperature (Topt) for denitrification was 36 °C and was observed in subtropical sediments, while the lowest Topt of 21 °C was observed at the polar site. Seasonal variation in the Topt was observed at the temperate site with values of 26 and 34 °C in winter and summer, respectively. The Topt values for anammox were 9 and 26 °C at the polar and temperate sites, respectively. The results demonstrate adaptation of denitrifying communities to in situ temperatures in permeable marine sediments across a wide range of temperatures, whereas marine anammox bacteria may be predominately psychrophilic to psychrotolerant. The adaptation of microbial communities to in situ temperatures suggests that the relationship between temperature and rates of N removal is highly dependent on community structure.

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