Heterogeneous Strata Research Articles

The relationship of lithological and thermobarogeochemical factors in fluid-active zones: A casestudy of the Krasnodonetsky district of Eastern Donbass

The distance of natural gas reservoirs from the country’s industrial centers, the irregularity of spreading of the reserves, the increased costs of gas production and supply, all contribute to the involvement of local and nonconventional resources in various-type production. Coal methane extraction in Eastern Donbass is a goal in this regard. The research included the field study of fluid-active methane-rich zones in coal seams in Eastern Donbass, as well as the lithological and thermobarogeochemical analyses of coal samples. The gas saturation of rocks was correlated with the material composition of deposits. The results of the work can be formulated as follows. Terrigenous rock sediments of age С27 feature the increased content of hydrocarbon gases. Most of methane is localized in the roof of commercialthickness coal seams overlaid with thin clayey shales, siltstones and sandstones of the scoured surface. The scoured-surface sandstone in the coal seam roof has good reservoir properties. The increased fluid permeability of rocks is due to cleavage, which is most intense in heterogeneous strata in the axial parts of small folds. The fluid-saturated zones in coal seams in terrigenous rocks of С27 age at a depth of 240–260 and 320–360 m contain signs of hydrothermal veined mineralization represented by pyrite, dickite, quartz and calcite. These fluidization zones feature high content of gases in coal seams (up to 40–42 m3/t) and enclosing rocks (up to 10–12 m3/t), which points at high prospects for the extraction of hydrocarbon gases from these zones.The study was carried out under the state contract with the Southern Scientific Center, Russian Academy of Sciences, State Registration No. 122020100352-6.

In situ stress inversion and fracture characteristics around local fault in deep heterogeneous strata

The southeast Sichuan in China is a key area for deep shale gas exploration. However, shale gas exploration in deep heterogeneous strata is greatly affected by in situ stress. Faults caused by tectonic movement strongly change the distribution of in situ stress. Inversion and prediction of in situ stress have become an important research hotspot in the field of resource exploitation. Based on the geological structure evolution and experimental data, the boundary stress iterative inversion method is used to inverse the in situ stress field of deep heterogeneous strata containing shale gas reservoirs, and the fracture characteristics around local fault are analyzed by fracture mechanics theory. The research shows that the stress field has the characteristics of non-uniform distribution under the influence of fault, and there is obvious stress concentration and deflection of principal stress direction around the fault. And magnitude and direction of stress are affected by the internal friction angle of the fault zone and the formation depth in different tectonic periods. Through the analysis and calculation of the plastic strain and stress intensity factors, it can be inferred that the cracks will propagate at the terminal portion of the fault. The research is important to guide engineering for the adjustment of resource exploitation scheme.

Environmental and technological factor diffusion with innovation and firm performance: Empirical evidence from manufacturing SMEs

The adoption of e-commerce is essential in today’s dynamic business environment to optimize the overall firm performance of manufacturing SMEs. This research investigates the influence of environmental and technological factors to promote e-commerce adoption and subsequent firm performance in manufacturing SMEs. Technology usage for sustainable production is becoming a global phenomenon, though it seems less prevalent in emerging economies. Fewer studies address technology adoption issues to enhance corporate performance in Pakistani manufacturing SMEs. The present study adopted a resource-based view with the diffusion of innovation theory to formulate a research framework. We chose a stratified proportionate random sampling method to collect data by selecting four heterogeneous strata. Out of 800 distributed questionnaires, 368 top- and middle-level managers of textile, leather, sports, and surgical SMEs of Pakistan returned the questionnaire. This study employed PLS-SEM for empirical analysis. The results showed that both the technological factors’ relative advantage and technology readiness have a significant positive relationship with the use of e-commerce. However, environmental factors, i.e., competitive pressure, have an insignificant effect on e-commerce usage. Nevertheless, the government support has a significant positive effect on e-commerce usage in SMEs. Overall, e-commerce adoption depicts a positive association with firm performance.

Triassic in the eastern Sichuan basin ray slope and badong group strata division and correlation

Triassic strata are widely developed in the eastern part of Sichuan Basin. The Mingyuexia anticline and Huangnitang anticline located in the eastern Sichuan structural belt develop Triassic Jialingjiang Formation to Xujiahe Formation. The middle Triassic Leikoupo Formation and Badong Formation on both sides of the anticline are synchronous and heterogeneous strata. They are distinguished regionally according to their different sedimentary environments and lithologic characteristics, and the phase transition boundary between Leikoupo Formation and Badong Formation is determined.

Stratified thermal response test measurement and analysis

An improved thermal response test method called the stratified thermal response test (STRT) was proposed and a corresponding system was developed in this study. The difference between the STRT and other methods is that the temperature was measured by sensors placed inside the borehole heat exchangers (BHEs) at different depths to obtain the virtual thermal conductivity in each stratum. The method was validated based on the measurements and determination of the thermal conductivities for two different sedimentary geological conditions using three approaches and was applied to determine the key heat transfer layer and the optimum buried depth of the vertical BHEs. The discrepancies between the thermal conductivities obtained by STRT and the conventional thermal response test were 2.5% and 2.7% respectively, which validates the reliability of the STRT. The positions of the key heat transfer layers of the two boreholes were 50–60 m and 60–80 m respectively; the location of the key heat transfer layer was affected by the intense groundwater activities. At the optimum buried depths of 80 m and 90 m for the two boreholes, the highest heat transfer rate per meter was obtained at the minimum cost. It is expected that the proposed STRT method and system will become increasingly useful for optimizing the depths of BHEs installed in heterogeneous strata because the installation cost can be minimized.

The Migration Diary of a Knickpoint in a Channelized Stream With a Cohesive Bed

AbstractThis paper examines the coevolutionary roles of variable flow features and heterogeneous substrates on knickpoint migration. A conceptual model is used to depict distinct migration mechanisms in a channelized headwater system of a representative intensively managed watershed in the Deep Loess Region of the U.S. Midwest. Throughout this region, entrenched streams have eroded into alluvial‐based strata that are horizontally consistent but vertically heterogeneous. Variable flow in these streams switches between vented conditions, where water shoots from the knickpoint face as an aerated plunging jet, and unvented conditions, where water clings close to its face through suction. These switches affect hydrodynamic mechanisms controlling migration but cannot explain fully observed alternating slow‐fast migration rates. It is hypothesized that vertically heterogeneous strata in entrenched streams, specifically strong‐over‐weak layers, facilitate observed changes in knickpoint migration rates. Preferential erosion of weaker sublayers is thought to trigger other erosional mechanisms to accelerate migration even at low flows. Herein, a migration “diary” documents a representative knickpoint's displacement over time with flow measurements and site stratigraphy. Slower migration occurred from 2006 to 2009 through fluvial erosion of a resistant silt loam cap. From 2009 to 2012, migration accelerated as the knickpoint face reached a critical height through scour. A flow back roller formed, which preferentially eroded a weaker sand sublayer. Undercutting/cantilever failure cycles persisted, causing 30 m of retreat within 2 months (i.e., 62.5% of the total migration over 78 months). Comparisons with established fluvial hydraulics‐based and undercutting/cantilever‐based migration models confirm the hypothesis and importance of both stratified substrates and hydrodynamic controls on knickpoint migration.

South West Hub CCS Project: Evolution of Storage Site Characterization through Targeted Research and its Impact on Uncertainty Reduction

The 2015 COP 21 meeting in Paris highlighted the urgency for more research into mitigation methods for greenhouse gases, yet there remain a small global portfolio of active investigations into large-scale geological storage of CO2. The South West Carbon Capture and Storage Hub in Western Australia is one of these projects, and is a greenfield investigation with little pre-existing subsurface data available to perform the required geological characterisation; thus acquiring geoscience data for the site has been a concentrated effort during the past several years. Research into the South West Hub project has focussed on acquiring and interpreting appropriate data to progressively refine the storage concept, and better understand and reduce uncertainties associated with the geological character of the storage site. The initial consideration for the South West Hub was to inject CO2 into Triassic sandstones in the southern Perth Basin at 2 to 3km depth near a structural feature known as the Harvey Ridge. In this concept containment of the CO2 was mainly through residual trapping within these deposits. Research is now focussing on the recognition of potential for a multi-containment system being present in the Triassic Lesueur Formation that includes the lower Wonnerup Member and upper Yalgorup Member. Injection would be into sandstones of the Wonnerup in which residual trapping can occur; the overlying Yalgorup potentially represents a series of strata that may impede upward migration of fluids, and comprises a succession of heterogeneous strata including a series of bands or pods of fine-grained and low permeability palaeosols which are up to 200 m thick beneath a sequence of interbedded clay-rich beds.3D seismic data obtained in 2014 have provided more clarity around subsurface structures, fault locations, orientations and insight into regional stress fields. Core and log data from three wells drilled in 2015 into the Yalgorup are helping to establish the depositional nature, stratigraphic correlation and regional continuity of the possible baffle units within this member. Core-based work on pore-scale processes is developing knowledge about the impacts of CO2 injected into Wonnerup sandstones and how it may be distributed and retained for long-term storage. Together the seismic and well data are being integrated toward more detailed static and dynamic models for simulations of trapping potential and long-term behaviour of injected CO2. Monitoring methods are being examined and field tested to establish environmental baselines and to ensure the ability to validate models and for public and regulatory assurance. Ongoing phases of research will continue to focus on reducing technical uncertainty at the South West Hub storage site. Addressing several outstanding questions about injectivity and containment at the site are driving additional research involving in situ well tests.

Improved estimation of hydraulic conductivity by combining stochastically simulated hydrofacies with geophysical data.

Hydraulic conductivity is a major parameter affecting the output accuracy of groundwater flow and transport models. The most commonly used semi-empirical formula for estimating conductivity is Kozeny-Carman equation. However, this method alone does not work well with heterogeneous strata. Two important parameters, grain size and porosity, often show spatial variations at different scales. This study proposes a method for estimating conductivity distributions by combining a stochastic hydrofacies model with geophysical methods. The Markov chain model with transition probability matrix was adopted to re-construct structures of hydrofacies for deriving spatial deposit information. The geophysical and hydro-chemical data were used to estimate the porosity distribution through the Archie’s law. Results show that the stochastic simulated hydrofacies model reflects the sedimentary features with an average model accuracy of 78% in comparison with borehole log data in the Chaobai alluvial fan. The estimated conductivity is reasonable and of the same order of magnitude of the outcomes of the pumping tests. The conductivity distribution is consistent with the sedimentary distributions. This study provides more reliable spatial distributions of the hydraulic parameters for further numerical modeling.

CarboCAT: A cellular automata model of heterogeneous carbonate strata

CarboCAT is a new numerical model of carbonate deposystems that uses a cellular automata to calculate lithofacies spatial distributions and hence to calculate the accumulation of heterogeneous carbonate strata in three dimensions. CarboCAT includes various geological processes, including tectonic subsidence, eustatic sea-level oscillations, water depth-dependent carbonate production rates in multiple carbonate factories, lateral migration of carbonate lithofacies bodies, and a simple representation of sediment transport. Results from the model show stratigraphically interesting phenomena such as heterogeneous strata with complex stacking patterns, laterally discontinuous subaerial exposure surfaces, nonexponential lithofacies thickness distributions, and sensitive dependence on initial conditions whereby small changes in the model initial conditions have a large effect on the final model outcome. More work is required to fully assess CarboCAT, but these initial results suggest that a cellular automata approach to modeling carbonate strata is likely to be a useful tool for investigating the nature and origins of heterogeneity in carbonate strata.

Stability hazard indicator system for slope failure in heterogeneous strata : Nathanail, C P; Earle, D A; Hudson, J A Proc ISRM Symposium: Eurock'92, Chester, 14–17 September 1992P111–116. Publ London: Thomas Telford, 1992

Stability hazard indicator system for slope failure in heterogeneous strata : Nathanail, C P; Earle, D A; Hudson, J A Proc ISRM Symposium: Eurock'92, Chester, 14–17 September 1992P111–116. Publ London: Thomas Telford, 1992

Ontology of the Work of Art: The Musical Work; The Picture; The Architectural Work; The Film

In these studies Roman Ingarden investigates the nature and mode of being of four kinds of art works: the musical work, the picture, the architectural work, and the film. He establishes that the work of art is a purely intentional object but considers also its connections to the real world. By analyzing a work of art in its “constitutive heterogeneous strata,” Ingarden demonstrates that a work of art will reveal, when examined in the appropriate way, its own inherent structure. Further, he shows that in consequence of the art work's structure, we must distinguish between the work itself and the concretizations of it by the listener or viewer. Ingarden elaborates upon the conception of concretization which he present in The Literary Work of Art and applies it to music and visual art. He also employs the concept of aspect to clarify the ontic structure of these art works and the distinction between the concretization of the work and the work itself. The distinction between the work's concretization - effectuated in the mental experiences of the listener or viewer - and the work itself serves to help Ingarden confirm and account for the work's intersubjective identity. The problem of aesthetic value, Ingarden maintains, can be fruitfully treated only after the ontic structure of art work has been clarified. His primary concern in Ontology of the Work of Art is to ascertain and describe that structure and the mode of existence of works of art. In addition, he offers several discussions of aesthetic value, showing in the m the connections between questions of aesthetic value and the structure of the work of art.

Estimating Relative Risk from Heterogeneous Strata

SummaryThe uncritical use of risk estimators can lead to serious bias. The estimation of overall risk ratios for heterogeneous strata and the weights used have been discussed recently. This paper starts with the definition of relative risk in the population, considering heterogeneous strata and a cofactor, using weight functions. From this general formula four different weight functions leading to four different overall measures of relative risk (RR1, RR1, RR3, RR4 ) are. derived as special cases. The estimability of the parameters in relation to the underlying sampling design is investigated. Consistent estimators are provided and the asymptotic distributions of the estimators are given for prospective cohort studies, case control studies with fixed strata and case control studies with given sample sizes. For some of the estimates the . asymptotic variances are given. It is shown that for case control studies with fixed strata neither the Mantel-Haenszel estimator nor another estimator of this class is consistent. An extension to more than two risk levels is provided and the relationships between various risk measures and other implications are commented on. A way is described to improve risk estimation by using information from the population. An example for cohort studies is given. Generally we propose to use RR3 , which lies between RR1 and RR2 and can be estimated more precisely using the sometimes available distribution of the cofactor in the population. If the relative risk across strata is heterogeneous, logistic models for the construction of a single risk indicator have some drawbacks.

Seismes artificiels

During the last few years, examples of man-made earthquakes have become more and more frequent; these earthquakes are related to several works: dams and reservoirs, pumping of waste waters injected into a deep well, aftershocks of an earthquake generated by an underground nuclear explosion. In the case of lake-reservoirs the comparison of the phenomena in these different examples leads to several remarks. 1. (1) The earthquake activity is particularly clear when the reservoir is deeper than 100 m. The height of the water seems to be more important than the total volume of the reservoir. 2. (2) In many cases, contrary to natural seismicity the strongest shocks follow after numerous foreshocks. 3. (3) The magnitude of the strongest shocks can exceed 6 (Kariba, Cremasta, Koyna). 4. (4) Some particular geological conditions are necessary for the release of the shocks: old faults (Lake Mead, Lake of Kariba, Lake of Vogorno, etc.…), diaclases with water-leakage (Oued Fodda, Monteynard dam), heterogeneous strata i.e., basalt with tuffs and breccia (Koyna dam). The change of pressures generated by the water flowing underground must have significance to the question of mechanism of man-made earthquakes. The part of tectonic stresses is probably overestimated in the interpretation of the shocks; the action of the fluid is more important, by lubrication of faults or of slipping-surfaces and by changes of pressures between underground blocks of various permeability. One can hope that the study of man-made earthquakes may help towards the prediction of natural earthquakes, particularly the swarms of earthquakes.