scholarly journals COMPUTER CODES OF GEOCHEMICAL MODELING USED TO WATER-ROCK INTERACTION SIMPLE AND COMPLEX SYSTEMS

2019 ◽  
Vol 16 (32) ◽  
pp. 108-118
Author(s):  
Marcos Antônio KLUNK ◽  
Sudipta DASGUPTA ◽  
Mohuli DAS ◽  
Paulo Roberto WANDER
Keyword(s):  
Complex Systems ◽  
Geochemical Modeling ◽  
Chemical Properties ◽  
Coupled Transport ◽  
Burial History ◽  
Batch Mode ◽  
Data Set ◽  
Rock Interaction ◽  
Geochemical Reactions ◽  
Geochemical Models

The numerical modeling of transport and reaction was used for the understanding of the evolution of the diagenetic processes and their importance in the characterization and prediction of oil reservoir quality. Geochemical models are represented by numerical equations based on the physical-chemical properties of minerals. There are many software’s available in the market to simulate systems and geochemical reactions. The codes are divided into three distinct categories: coupled transport of reaction, modeling speciation, and batch mode according to the numerical method. Simple systems have clear connections between inputs and outputs. Complex systems have multiple factors that provide a probability distribution of data inputs that interact in specific functions. The outputs produced as a result are therefore impossible to predict with complete accuracy. Several research groups tried to develop numerical codes for geochemical modeling. The critical factors for the use of these systems are (i) verification of the simulation results with empirical data set and (ii) sensitivity analysis of these results, for the construction of general models which provide a predictive character. This last factor is particularly important as it establishes the qualitative and quantitative impact of each parameter in the simulations. Thus, with a complete numerical model diagenetic, it is possible to perform various simulations modifying one or the other parameter to test the sensitivity in the construction of these different geological scenarios. This set includes mineral composition and texture, the composition of fluids, paragenetic sequence, and burial history. This work brings fundamental concepts related to this topic as well as an analysis of commercial software available.

scholarly journals Hydrothermal Alteration at the San Vito Area of the Campi Flegrei Geothermal System in Italy: Mineral Review and Geochemical Modeling

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 810
Author(s):  
Monica Piochi ◽  
Barbara Cantucci ◽  
Giordano Montegrossi ◽  
Gilda Currenti
Keyword(s):  
Reactive Transport ◽  
Numerical Models ◽  
Geochemical Modeling ◽  
Relevant Information ◽  
Campi Flegrei ◽  
Geothermal System ◽  
Data Set ◽  
Rock Interaction ◽  
Geochemical Model ◽  
Rock Formations

The Campi Flegrei geothermal system sets in one of the most famous and hazardous volcanic caldera in the world. The geothermal dynamics is suspected to have a crucial role in the monitored unrest phases and in the eruption triggering as well. Numerical models in the literature do not properly consider the geochemical effects of fluid-rock interaction into the hydrothermal circulation and this gap limits the wholly understanding of the dynamics. This paper focuses on fluid-rock interaction effects at the Campi Flegrei and presents relevant information requested for reactive transport simulations. In particular, we provide: (1) an extensive review of available data and new petrographic analyses of the San Vito cores rearranged in a conceptual model useful to define representative geochemical and petrophysical parameters of rock formations suitable for numerical simulations and (2) the implemented thermodynamic and kinetic data set calibrated for the San Vito 1 well area, central in the geothermal reservoir. A preliminary 0D-geochemical model, performed with a different contribution of CO2 at high (165 °C) and low (85 °C) temperatures, firstly allows reproducing the hydrothermal reactions over time of the Campanian Ignimbrite formation, the most important deposits in the case study area.

scholarly journals Geochemical modeling of the Cu-Ag deposits from the Lubin-Głogów Copper District (Poland) supported by lithological modeling

2017 ◽  
Vol 33 (4) ◽  
pp. 63-78 ◽  
Author(s):  
Monika Wasilewska-Błaszczyk ◽  
Jacek Mucha
Keyword(s):  
Ordinary Kriging ◽  
Geochemical Modeling ◽  
3D Models ◽  
Statistical Characteristics ◽  
Random Component ◽  
Weighting Method ◽  
Data Set ◽  
Cu Content ◽  
Geochemical Models ◽  
Inverse Distance

Abstract The most important reasons for the limited credibility of 3D geochemical models of the Cu-Ag deposits (The Lubin-Głogów Copper District) are unfavorable statistical characteristics of the main metals (Cu, Ag), and the unfavorable structure of their variability with a relatively poorly marked non-random component of variability. It is hoped that the accuracy of geochemical models can be increased by previous lithological modeling of a given deposit. This is due to significant differences in mean Cu content in both the main lithological series (carbonates, shales and sandstones) and individual lithological units within them, which justifies separate geochemical modeling of each. The paper presents the results of the comparison of the reliability of 3D modeling of Cu content carried out in both individual and main lithological units of the Cu-Ag Rudna deposit (The Lubin- Głogów Copper District). The 3D lithological models were made using ordinary kriging (main lithological units) and Plurigaussian simulation (individual lithological units). The 3D estimation of Cu content within lithological models was carried out using the ordinary kriging (OK ) and squared inverse distance (ID2) methods. The verification of the accuracy of Cu estimates in the 3D model using spot samples of the test data set has shown only a slight increase in the accuracy of the estimates of Cu content within the individual lithological units of the shale series compared to the estimates of Cu content in the whole main lithology. In most cases, 3D models of Cu content carried out using the ordinary kriging method are slightly more accurate than the analogous squared inverse distance weighting method.

Calcareous nannoplankton ecology and community change across the Paleocene-Eocene Thermal Maximum

Paleobiology ◽  
10.1666/12050 ◽  
2013 ◽  
Vol 39 (4) ◽  
pp. 628-647 ◽  
Author(s):  
Leah J. Schneider ◽  
Timothy J. Bralower ◽  
Lee R. Kump ◽  
Mark E. Patzkowsky
Keyword(s):  
Nutrient Availability ◽  
Multivariate Analyses ◽  
Geochemical Modeling ◽  
Community Change ◽  
Open Ocean ◽  
Data Set ◽  
Long Term Effect ◽  
Term Change ◽  
Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM; ca. 55.8 Ma) is thought to coincide with a profound but entirely transient change among nannoplankton communities throughout the ocean. Here we explore the ecology of nannoplankton during the PETM by using multivariate analyses of a global data set that is based upon the distribution of taxa in time and space. We use these results, coupled with stable isotope data and geochemical modeling, to reinterpret the ecology of key genera. The results of the multivariate analyses suggest that the community was perturbed significantly in coastal and high-latitudes sites compared to the open ocean, and the relative influence of temperature and nutrient availability on the assemblage varies regionally. The open ocean became more stratified and less productive during the PETM and the oligotrophic assemblage responded primarily to changes in nutrient availability. Alternatively, assemblages at the equator and in the Southern Ocean responded to temperature more than to nutrient reduction. In addition, the assemblage change at the PETM was not merely transient—there is evidence of adaptation and a long-term change in the nannoplankton community that persists after the PETM and results in the disappearance of a high-latitude assemblage. The long-term effect on communities caused by transient warming during the PETM has implications for modern-day climate change, suggesting similar permanent changes to nannoplankton community structure as the oceans warm.

Reliability-based covariate analysis for complex systems in heterogeneous environment: Case study of mining equipment

2018 ◽  
Vol 233 (4) ◽  
pp. 593-604
Author(s):  
Amin Moniri-Morad ◽  
Mohammad Pourgol-Mohammad ◽  
Hamid Aghababaei ◽  
Javad Sattarvand
Keyword(s):  
Complex Systems ◽  
Cox Regression ◽  
Reliability Evaluation ◽  
Distribution Functions ◽  
Heterogeneous Environment ◽  
Mining Equipment ◽  
Data Set ◽  
Explanatory Variables ◽  
The Impact

Operational heterogeneity and harsh environment lead to major variations in production system performance and safety. Traditional probabilistic model is dealt with time-to-event data analysis, which does not have the capability of quantifying and simulation of these types of complexities. This research proposes an integrated methodology for analyzing the impact of dominant explanatory variables on the complex system reliability. A flexible parametric proportional hazards model is developed by focusing on standard parametric Cox regression model for reliability evaluation in complex systems. To achieve this, natural cubic splines are utilized to create a smooth and flexible baseline hazards function where the standard parametric distribution functions do not fit into the failure data set. A real case study is considered to evaluate the reliability for multi-component mechanical systems such as mining equipment. Different operational and environmental explanatory variables are chosen for the analysis process. Research findings revealed that precise estimation of the baseline hazards function is a major part of the reliability evaluation in heterogeneous environment. It is concluded that an appropriate maintenance strategy potentially mitigate the equipment failure intensity.

scholarly journals Geochemical Modeling of Scale Formation due to Cooling and CO2-degassing in San Kamphaeng Geothermal Field, Northern Thailand

2021 ◽  
Vol 20 (3) ◽  
Author(s):  
Sutthipong Taweelarp ◽  
Supanut Suntikoon ◽  
Thaned Rojsiraphisal ◽  
Nattapol Ploymaklam ◽  
Schradh Saenton
Keyword(s):  
Carbon Dioxide ◽  
Hot Springs ◽  
Hot Spring ◽  
Geochemical Modeling ◽  
Chemical Properties ◽  
Geothermal Field ◽  
Spring Water ◽  
Northern Thailand ◽  
Scaling Potential ◽  
Co2 Degassing

Scaling in a geothermal piping system can cause serious problems by reducing flow rates and energy efficiency. In this work, scaling potential of San Kamphaeng (SK) geothermal energy, Northern Thailand was assessed based on geochemical model simulation using physical and chemical properties of hot spring water. Water samples from surface seepage and groundwater wells, analyzed by ICP-OES and ion chromatograph methods for chemical constituents, were dominated by Ca-HCO3 facies having partial pressure of carbon dioxide of 10–2.67 to 10–1.75 atm which is higher than ambient atmospheric CO2 content. Surface seepage samples have lower temperature (60.9°C) than deep groundwater (83.1°C) and reservoir (127.1°C, based on silica geothermometry). Geochemical characteristics of the hot spring water indicated significant difference in chemical properties between surface seepage and deep, hot groundwater as a result of mineral precipitation along the flow paths and inside well casing. Scales were mainly composed of carbonates, silica, Fe-Mn oxides. Geochemical simulations based on multiple chemical reaction equilibria in PHREEQC were performed to confirm scale formation from cooling and CO2-degassing processes. Simulation results showed total cumulative scaling potential (maximum possible precipitation) from 267-m deep well was estimated as 582.2 mg/L, but only 50.4% of scaling potential actually took place at SK hot springs. In addition, maximum possible carbon dioxide outflux to atmosphere from degassing process in SK geothermal field, estimated from the degassing process, was 6,960 ton/year indicating a continuous source of greenhouse gas that may contribute to climate change. Keywords: Degassing, Geochemical modeling, PHREEQC, San Kamphaeng Hot Springs, Scaling

scholarly journals iCn3D: from Web-based 3D Viewer to Structure Analysis Tool in Batch Mode

2021 ◽  
Author(s):  
Jiyao Wang ◽  
Philippe Youkharibache ◽  
Aron Marchler-Bauer ◽  
Christopher Lanczycki ◽  
Dachuan Zhang ◽  
...  
Keyword(s):  
Protein Interaction ◽  
Large Data ◽  
Accessible Surface Area ◽  
Solvent Accessible Surface Area ◽  
Analysis Tool ◽  
Batch Mode ◽  
Data Set ◽  
Web Based ◽  
Protein Protein Interaction ◽  
Link Type

AbstractiCn3D was originally released as a web-based 3D viewer, which allows users to create a custom view in a life-long, shortened URL to share with colleagues. Recently, iCn3D was converted to use JavaScript classes and could be used as a library to write Node.js scripts. Any interactive features in iCn3D can be converted to Node.js scripts to run in batch mode for a large data set. Currently the following Node.js script examples are available at https://github.com/ncbi/icn3d/tree/master/icn3dnode: ligand-protein interaction, protein-protein interaction, change of interactions due to residue mutations, DelPhi electrostatic potential, and solvent accessible surface area. iCn3D PNG images can also be exported in batch mode using a Python script. Other recent features of iCn3D include the alignment of multiple chains from different structures, realignment, dynamic symmetry calculation for any subsets, 2D cartoons at different levels, and interactive contact maps. iCn3D can also be used in Jupyter Notebook as described at https://pypi.org/project/icn3dpy.

Uniqueness

1996 ◽  
Author(s):  
Craig M. Bethke
Keyword(s):  
Geochemical Modeling ◽  
Theoretical Work ◽  
Input Constraints ◽  
Governing Equations ◽  
Single Root ◽  
Rate Laws ◽  
Starting Point ◽  
The Subject ◽  
Geochemical Models ◽  
Practical Question

A practical question that arises in quantitative modeling is whether the results of a modeling study are unique. In other words, is it possible to arrive at results that differ, at least slightly, from the original ones but nonetheless satisfy the governing equations and honor the input constraints? In the broadest sense, of course, no model is unique (see, for example, Oreskes et al., 1994). A geochemical modeler could conceptualize the problem differently, choose a different compilation of thermodynamic data, include more or fewer species and minerals in the calculation, or employ a different method of estimating activity coefficients. The modeler might allow a mineral to form at equilibrium with the fluid or require it to precipitate according to any of a number of published kinetic rate laws and rate constants, and so on. Since a model is a simplified version of reality that is useful as a tool (Chapter 2), it follows that there is no“correct” model, only a model that is most useful for a given purpose. A more precise question (Bethke, 1992) is the subject of this chapter: in geochemical modeling is there but a single root to the set of governing equations that honors a given set of input constraints? We might call such a property mathematical uniqueness, to differentiate it from the broader aspects of uniqueness. The property of mathematical uniqueness is important because once the software has discovered a root to a problem, the modeler may abandon any search for further solutions. There is no concern that the choice of a starting point for iteration has affected the answer. In the absence of a demonstration of uniqueness, on the other hand, the modeler cannot be completely certain that another solution, perhaps a more realistic or useful one, remains undiscovered. Geochemists, following early theoretical work in other fields, have long considered the multicomponent equilibrium problem (as defined in Chapter 3) to be mathematically unique. In fact, however, this assumption is not correct. Although relatively uncommon, there are examples of geochemical models in which more than one root of the governing equations satisfy the modeling constraints equally well. In this chapter, we consider the question of uniqueness and pose three simple problems in geochemical modeling that have nonunique solutions.

scholarly journals HFSE‐REE Transfer Mechanisms During Metasomatism of a Late Miocene Peraluminous Granite Intruding a Carbonate Host (Campiglia Marittima, Tuscany)

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 682
Author(s):  
Paoli ◽  
Dini ◽  
Petrelli ◽  
Rocchi
Keyword(s):  
External Source ◽  
Magmatic Fluid ◽  
Chemical Components ◽  
Fluid Composition ◽  
Peraluminous Granite ◽  
Rock Interaction ◽  
Complete Replacement ◽  
Element Mobilization ◽  
Geochemical Models ◽  
Metasomatic Event

The different generations of calc‐silicate assemblages formed during sequential metasomatic events make the Campiglia Marittima magmatic–hydrothermal system a prominent case study to investigate the mobility of rare earth element (REE) and other trace elements. These mineralogical assemblages also provide information about the nature and source of metasomatizing fluids. Petrographic and geochemical investigations of granite, endoskarn, and exoskarn bodies provide evidence for the contribution of metasomatizing fluids from an external source. The granitic pluton underwent intense metasomatism during post‐magmatic fluid–rock interaction processes. The system was initially affected by a metasomatic event characterized by circulation of K‐rich and Ca(‐Mg)‐rich fluids. A potassic metasomatic event led to the complete replacement of magmatic biotite, plagioclase, and ilmenite, promoting major element mobilization and crystallization of K‐feldspar, phlogopite, chlorite, titanite, and rutile. The process resulted in significant gain of K, Rb, Ba, and Sr, accompanied by loss of Fe and Na, with metals such as Cu, Zn, Sn, W, and Tl showing significant mobility. Concurrently, the increasing fluid acidity, due to interaction with Ca‐rich fluids, resulted in a diffuse Ca‐metasomatism. During this stage, a wide variety of calc‐silicates formed (diopside, titanite, vesuvianite, garnet, and allanite), throughout the granite body, along granite joints, and at the carbonate–granite contact. In the following stage, Ca‐F‐rich fluids triggered the acidic metasomatism of accessory minerals and the mobilization of high-field-strength elements (HFSE) and REE. This stage is characterized by the exchange of major elements (Ti, Ca, Fe, Al) with HFSE and REE in the forming metasomatic minerals (i.e., titanite, vesuvianite) and the crystallization of HFSE‐REE minerals. Moreover, the observed textural disequilibrium of newly formed minerals (pseudomorphs, patchy zoning, dissolution/reprecipitation textures) suggests the evolution of metasomatizing fluids towards more acidic conditions at lower temperatures. In summary, the selective mobilization of chemical components was related to a shift in fluid composition, pH, and temperature. This study emphasizes the importance of relating field studies and petrographic observations to detailed mineral compositions, leading to the construction of litho‐geochemical models for element mobilization in crustal magmatic‐hydrothermal settings.

3D seismic imaging of volcanogenic massive sulfide deposits in the Flin Flon mining camp, Canada: Part 2 — Forward modeling

Geophysics ◽  
2012 ◽  
Vol 77 (5) ◽  
pp. WC81-WC93 ◽  
Author(s):  
Michal Malinowski ◽  
Ernst Schetselaar ◽  
Donald J. White
Keyword(s):  
Synthetic Data ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Earth Model ◽  
Seismic Modeling ◽  
Volcanogenic Massive Sulfide ◽  
Data Set ◽  
Rock Interaction ◽  
Time Migration ◽  
Flin Flon

We applied seismic modeling for a detailed 3D geologic model of the Flin Flon mining camp (Canada) to address some imaging and interpretation issues related to a [Formula: see text] 3D survey acquired in the camp and described in a complementary paper (part 1). A 3D geologic volumetric model of the camp was created based on a compilation of geologic data constraints from drillholes, surface geologic mapping, interpretation of 2D seismic profiles, and 3D surface and grid geostatistical modeling techniques. The 3D modeling methodology was based on a hierarchical approach to account for the heterogeneous spatial distribution of geologic constraints. Elastic parameters were assigned within the model based on core sample measurements and correlation with the different lithologies. The phase-screen algorithm used for seismic modeling was validated against analytic and finite-difference solutions to ensure that it provided accurate amplitude-variation-with-offset behavior for dipping strata. Synthetic data were generated to form zero-offset (stack) volume and also a complete prestack data set using the geometry of the real 3D survey. We found that the ability to detect a clear signature of the volcanogenic massive sulfide with ore deposits is dependent on the mineralization type (pyrite versus pyrrhotite rich ore), especially when ore-host rock interaction is considered. In the presence of an increasing fraction of the host rhyolite rock within the model volume, the response from the lower impedance pyrrhotite ore is masked by that of the rhyolite. Migration tests showed that poststack migration effectively enhances noisy 3D DMO data and provides comparable results to more computationally expensive prestack time migration. Amplitude anomalies identified in the original 3D data, which were not predicted by our modeling, could represent potential exploration targets in an undeveloped part of the camp, assuming that our a priori earth model is sufficiently accurate.

Climatic and oceanographic isotopic signals from the carbonate rock record and their preservation

1992 ◽  
Vol 129 (2) ◽  
pp. 143-160 ◽  
Author(s):  
James D. Marshall
Keyword(s):  
Ocean Circulation ◽  
Global Climate ◽  
Burial History ◽  
Vegetative Cover ◽  
Isotopic Data ◽  
Rock Interaction ◽  
Diagenetic Alteration ◽  
Wide Range ◽  
History Of ◽  
Diagenetic History

AbstractStable isotopic data from marine limestones and their constituent fossils and marine cements can provide quantitative evidence for changes in global climate and ocean circulation. Oxygen isotopic data can indicate changes in temperature and ocean composition whereas stratigraphic variation in carbon isotope ratios may reflect changes in the carbon cycle that can be linked to changes in oceanic productivity and atmospheric greenhouse gases. Terrestrial carbonates–meteoric cements, calcretes and speleothems–similarly offer significant potential for understanding the evolution of terrestrial climates by providing evidence for the composition of rainwater and the nature of vegetative cover.Primary environmental isotopic signals may be obscured by the effects of post-depositional diagenetic alteration. Cementation and replacement reactions can take place in a wide range of diagenetic environments; the diagenetic history of an individual limestone is determined by a combination of its mineralogical diagenetic potential and depositional setting, together with subsequent changes in relative sea-level and burial history. Carbon isotopic values are less prone to alteration during diagenesis than oxygen values but shifts can be significant where organogenic carbon is incorporated. Linear covariation of carbon and oxygen values is not a reliable indicator of diagenetic alteration: water-rock interaction and fluid mixing may produce non-linear distributions.Attempts to determine long-term changes in climatic and oceanographie conditions through isotope stratigraphy of shallow-water limestones must include an assessment of the diagenetic history of the materials analysed. Pétrographic examination using conventional microscopy backed up, where appropriate, by cathodoluminescence and scanning electron microscopy together with elemental and strontium isotopic analysis can help to identify the effects of diagenetic alteration. Where material with a range of different degrees of alteration is preserved in the same sediment it may be possible to compare patterns of isotopic and elemental variation and to attempt to unravel the effects of diagenesis in order to determine primary, environmental, isotopic signals. Recent research has shown that these techniques can be successfully employed in both Phanerozoic and Precambrian sediments.

Sign in / Sign up

Export Citation Format

Share Document