Sedimentary and organic facies investigation of the Gurpi Formation (Campanian–Paleocene) in southwest of Zagros,Iran

The Gurpi Formation in the southwest of Iran has been studied for microfacies and bulk organic geochemistry in order to elucidate its depositional environment and petroleum source rock characteristics. The obtained results ended up with four types of organic facies and three types of microfacies through the formation. Three microfacies types differentiated including Pelagic mudstone Wackstone, microbioclast Packstone and bioclastic Packstone reflect a distal outer ramp or basinal environment. Combination of palynofacies and organic geochemistry resulted in differentiation of four organic facies corresponding to organic facies B, BC, C and CD of Jones 1987. Detailed organic facies shows that the formation is characterized by low values of TOC, high percentages of amorphous organic matter and black phytoclasts, rare marine algae thereby representing a mixture of terrestrial and marine kerogen that confirm the formation was deposited in a distal anoxic to oxic condition. The formation shallows upward to the Microbioclast Packstone facies below the Lopha Member reaching its minimum depth in boundstones of this member in uppermost Campanian and then is followed by stagnant condition and high contents of organic matter in suboxic to anoxic condition that favoured accumulation of organic matter in early Maastrichtian. Organic geochemical and petrographical data indicate that the formation is not potentially suitable for petroleum production except for the minor interval (organic facies 2) in early Maastrichtian. Tmax values vary between 340 and 440 °C confirming immaturity trends indicated by Rock-Eval data.     

Lithological facies identification in Iranian largest gas field: A comparative study of neural network methods

Determination of different facies in an underground reservoir with the aid of various applicable neural network methods can improve the reservoir modeling. Accordingly facies identification from well logs and cores data information is considered as the most prominent recent tasks of geological engineering. The aim of this study is to analyze and compare the five artificial neural networks (ANN) approaches with identification of various structures in a rock facies and evaluate their capability in contrast to the labor intensive conventional method. The selected networks considered are Backpropagation Neural Networks (BPNN), Radial Basis Function (RBF), Probabilistic Neural Networks (PNN), Competitive Learning (CL) and Learning Vector Quantizer (LVQ). All these methods have been applied in four wells of South Pars field, Iran. Data of three wells were employed for the networks training purpose and the fourth one was used to test and verify the trained network predictions. The results have demonstrated that all approaches have the ability of facies modeling with more than 65% of precision. According to the performed analysis, RBF, CL and LVQ methods could model the facies with the accuracy between 66 and 68 percent while PNN and BPNN techniques are capable of making predictions with more than 72% and 88.5% of precision, respectively. It can be concluded that the BPNN can generate most accurate results in comparison to the other type of networks but it is important to note that the other factors such as consuming the amount of time taken, simplicity and the less adjusted parameters as well as the acquired precisions should be considered. As a result, the model evaluation analysis used in this study can be useful for prospective surveys and cost benefit facies identification.     

Prediction of global stability in room and pillar coal mines

Global stability is a necessary prerequisite for safe retreat mining and one of the crucial and complex problems in room and pillar mining, so its prediction plays an important role in the safety of retreat mining and the reduction of pillar failure risk. In this study, we have tried to develop predictive models for anticipating global stability. For this purpose, two of the most popular techniques, logistic regression analysis and fuzzy logic, were taken into account and a predictive model was constructed based on each. For training and testing of these models, a database including 80 retreat mining case histories from 18 room and pillar coal mines, located in West Virginia State, USA, was used. The models predict global stability based on the major contributing parameters of pillar stability. It was found that both models can be used to predict the global stability, but the comparison of two models, in terms of statistical performance indices, shows that the fuzzy logic model provides better results than the logistic regression. These models can be applied to identify the susceptibility of pillar failure in panels of coal mines, and this may help to reduce the casualties resulting from pillar instability. Finally, the sensitivity analysis was performed on database to determine the most important parameters on global stability. The results revealed that the pillar width is the most important parameter, whereas the depth of cover is the least important one.     

Correction to: New climatic zones in Iran: a comparative study of different empirical methods and clustering technique

Theoretical and Applied Climatology -     

Interacting new agegraphic dark energy in a cyclic universe

The main goal of this work is investigation of NADE in the cyclic universe scenario. Since, cyclic universe is explained by a phantom phase (ω<−1), it is shown when there is no interaction between matter and dark energy, ADE and NADE do not produce a phantom phase, then can not describe cyclic universe. Therefore, we study interacting models of ADE and NADE in the modified Friedmann equation. We find out that, in the high energy regime, which it is a necessary part of cyclic universe evolution, only NADE can describe this phantom phase era for cyclic universe. Considering deceleration parameter tells us that the universe has a deceleration phase after an acceleration phase, and NADE is able to produce a cyclic universe. Also it is found valuable to study generalized second law of thermodynamics. Since the loop quantum correction is taken account in high energy regime, it may not be suitable to use standard treatment of thermodynamics, so we turn our attention to the result of Li et al. (Adv. High Energy Phys. 2009: 905705, 2009), which the authors have studied thermodynamics in loop quantum gravity, and we show that which condition can satisfy generalized second law of thermodynamics.     

Application of the honey-bees mating programming (HBMP) algorithm to sediment concentration modelling

Abstract

The honey-bees mating programming (HBMP) algorithm is introduced as a novel tool for predicting suspended sediment concentration for the Mad River catchment near Arcata, USA. The paper also applies gene expression programming (GEP) as a comparison and shows that these two approaches can the produce transparent, nonlinear relationships between the independent and dependent variables. Some modifications have been made to the HBMP algorithm to improve its capability and efficiency. The results achieved from this method and GEP are compared with two different sediment rating curves based on regression techniques. The findings show that the results from both the HBMP and GEP methods are promising and outperform the results obtained from the sediment rating curves.

Editor D. Koutsoyiannis; Associate editor L. See     

A multicriteria spatial decision support system for solving emergency service station location problems

Earthquakes occurring in urban areas constitute an important concern for emergency management and rescue services. Emergency service location problems may be formulated in discrete space or by restricting the potential location(s) to a specified finite set of points in continuous space. We propose a Multicriteria Spatial Decision Support System to identify shelters and emergency service locations in urban evacuation planning. The proposed system has emerged as an integration of the geographical information systems (GIS) and the multicriteria Decision-Making method of Preference Ranking Organization Method for Enrichment Evaluation IV (PROMETHEE IV). This system incorporates multiple and often conflicting criteria and decision-makers’ preferences into a spatial decision model. We consider three standard structural attributes (i.e., durability density, population density, and oldness density) in the form of spatial maps to determine the zones most vulnerable to an earthquake. The information on these spatial maps is then entered into the ArcGIS software to define the relevant scores for each point with regards to the aforementioned attributes. These scores will be used to compute the preference functions in PROMETHEE IV, whose net flow outranking for each alternative will be inputted in ArcGIS to determine the zones that are most vulnerable to an earthquake. The final scores obtained are integrated into a mathematical programming model designed to find the most suitable locations for the construction of emergency service stations. We demonstrate the applicability of the proposed method and the efficacy of the procedures and algorithms in an earthquake emergency service station planning case study in the city of Tehran.     

Kinetic modeling of carbon and nutrients removal in an integrated rotating biological contactor-activated sludge system

In this study, kinetics of biological carbon, nitrogen, and phosphorous removal from a synthetic wastewater in an integrated rotating biological contactor-activated sludge system was investigated. The experimental data obtained from varying four significant independent factors viz., hydraulic retention time, chemical oxygen demand for nitrogen to phosphorus ratio, internal recirculation from aerobic to anoxic zone and disks rotating speed were used for the process kinetic modeling. In order to obtain the bioprocess kinetic coefficients, Monod, first-order and Stover?CKincannon models were employed. As a result, Monod and Stover?CKincannon models were found to be the appropriate models to describe the bioprocess in the rotating biological contactor-activated sludge system as the determination coefficient for the first-order model obtained less than 0.79. According to the Monod model, growth yield, microbial decay rate, maximum specific biomass growth rate, and half-velocity constant coefficients were found to be 0.712?g VSS/g COD, 0.008/d, 5.54/d and 55?mg COD/L, respectively. From Stover?CKincannon model, the maximum total substrate removal rate constant and half-velocity constant were determined as 15.2, 10.98, 12.05?g/L?d and 14.78, 7.11, 6.97?mg/L for chemical oxygen demand, nitrogen and phosphorus removal, respectively. The kinetic parameters determined in this study can be used to improve the design and operation of the biological contactor-activated sludge system in full scale.     

Mechanical and Physical Characterization of Tabriz Marls, Iran

Three types of marls can be found in the Tabriz area (Iran): yellow, green, and gray/black marls. In the present paper, strength and deformation characteristics of Tabriz marls and their stress–strain behavior are investigated by various in situ and laboratory tests. In order to study the deformation behavior of these marls, various experiments such as the pressuremeter test, plate loading test (PLT), seismic wave velocity test, uniaxial compression test, standard penetration test (SPT), and direct shear test were carried out. Ranges of strain at the elastic and failure points were determined. Young’s and shear modulus were obtained. Test results showed that the strength characteristics increase with depth. The value of deformation modulus determined by the pressuremeter test was in good agreement with those obtained from the PLT. This implies that pressuremeter is a suitable in situ test for characterizing the deformation modulus of marl. Deformation modulus obtained from pressuremeter and plate loading tests were approximately 4–5 times the results of uniaxial compressive test and the deformation modulus obtained from seismic data was about 30–50 times the static deformation modulus. Stress–strain curves showed that the maximum value of strain at the elastic and failure points and the minimum value of strength and deformation modulus are corresponding to the yellow marls while the minimum value of strain and the maximum value of strength and deformation modulus are corresponding to the gray/black marls. Some empirical relationships between different characteristics of Tabriz marls were also derived.     

Assessing flow paths in a karst aquifer based on multiple dye tracing tests using stochastic simulation and the MODFLOW-CFP code

Karst systems show high spatial variability of hydraulic parameters over small distances and this makes their modeling a difficult task with several uncertainties. Interconnections of fractures have a major role on the transport of groundwater, but many of the stochastic methods in use do not have the capability to reproduce these complex structures. A methodology is presented for the quantification of tortuosity using the single normal equation simulation (SNESIM) algorithm and a groundwater flow model. A training image was produced based on the statistical parameters of fractures and then used in the simulation process. The SNESIM algorithm was used to generate 75 realizations of the four classes of fractures in a karst aquifer in Iran. The results from six dye tracing tests were used to assign hydraulic conductivity values to each class of fractures. In the next step, the MODFLOW-CFP and MODPATH codes were consecutively implemented to compute the groundwater flow paths. The 9,000 flow paths obtained from the MODPATH code were further analyzed to calculate the tortuosity factor. Finally, the hydraulic conductivity values calculated from the dye tracing experiments were refined using the actual flow paths of groundwater. The key outcomes of this research are: (1) a methodology for the quantification of tortuosity; (2) hydraulic conductivities, that are incorrectly estimated (biased low) with empirical equations that assume Darcian (laminar) flow with parallel rather than tortuous streamlines; and (3) an understanding of the scale-dependence and non-normal distributions of tortuosity.