Experimental petrology provides a direct means of constraining mineral phase stability and primary magma compositions across a wide range of pressure – temperature (P-T) conditions. By precisely controlling parameters such as pressure, temperature, and oxygen fugacity (fO2), researchers can test both synthetic and natural compositions under specific regimes. Given the direct inaccessibility of the Earth’s mantle, such experimental investigations are essential for interpreting deep Earth processes, including phase equilibria and melt generation. This paper reviews the fundamental principles of experimental petrology and critically reviews experimental studies on dry, hydrous, and carbonated mantle systems, as well as peridotite – eclogite hybrid sources.
Abstract Drilling is a complex destructive action that induces vibrations due to the rock-bit interaction, which affects the overall drilling efficiency and wellbore quality. This study aims to enhance drilling efficiency by deploying artificial neural networks (ANNs) to integrate in-cutter force sensing and vibration data. Data is collected from experiments conducted with sharp cutters on rock samples of varying mechanical properties, measuring variables such as weight on bit, torque, rotational speed, in-cutter force, and vibration measurements. A scoring system is used to evaluate the drilling efficiency by coupling the mechanical specific energy and vibration modes. An ANN is trained with these variables to predict the rate of penetration and rock strength, which are also measured in the experiments to be used as ground truth. The reliability of the framework is demonstrated by testing the validity of the ANN model on samples with various mechanical properties. It introduces a reliable and swift method for determining optimal drilling parameters, supported by a sensitivity analysis to fine-tune the ANN and assess the influence of each parameter on performance. This study demonstrates that ANN could be successfully implemented to predict the rate of penetration and rock strength on a laboratory-scaled drilling rig. The results show that the ANN model accurately predicts training and testing datasets for scoring while drilling multiple layers with a correlation coefficient of 0.966. Integration of in-cutter sensing technology, vibration data, and ANN can be of significant interest and be used on field applications to provide a reliable and rapid decision about drilling efficiency.
The tectonic evolution of the Paleo-Asian Ocean (PAO) has been well studied, including its gradual narrowing and closure by subduction. However, aspects of the tectonic evolution of the oceanic domain remain unclear, including the exact timing and nature of the closure. The Central Asian Orogenic Belt (CAOB) was formed by the closure of the PAO and, therefore, contains information about the tectonic evolution of the oceanic domain. Here, we report a study of the petrology, geochronology, and geochemistry of the Taohaiyingzi section of the Permian Linxi Formation in Alukhorqin Banner (Northeast China) in the central part of the CAOB. A newly discovered andesitic tuff from the lower part of the Linxi Formation yields a weighted mean 206Pb/238U age of 262.2 ± 1.1 Ma (n = 87), indicating that the lower part of the Linxi Formation of the Taohaiyingzi section was deposited during the late Guadalupian. Provenance weathering indicators show that the sedimentary rocks of the Linxi Formation are of low maturity. Element geochemical characteristics indicate that the Linxi Formation clastic rocks were derived from eroded magmatic rocks that formed in a continental arc setting and were deposited close to the arc in a continental arc basin environment. The active margin setting was generated by the subduction of the paleo-Asian oceanic plate beneath the Xilinhot–Songliao block. The inferred palaeosalinity of the sedimentary environment changed gradually from brackish to fresh water, suggesting the end of oceanic plate subduction during the late Guadalupian, and the closure of the PAO during or after the Lopingian.
Ramachandran Dhavamani, Radovan Pipík, Valentín Sočuvka
et al.
The data presented in this paper are related to the research article “Sub-bottom and bathymetry sonar inspection of postglacial lacustrine infill of the alpine lakes (Tatra Mts., Slovakia)” (Dhavamani et al., 2022). An implementation of acoustic sonar protocols provided data for the interpretation of glacigene, glaciolacustrine, postglacial, mass-movement deposits, and geodynamic factors influencing the sedimentation in seven alpine and sub-alpine Tatra Mountains lakes. The field data document the survey track lines of the sonars and allow to identify the location of the geomorphologic phenomena described in (Dhavamani et al., 2022). The laboratory data obtained by micro-CT document the lithology of glaciolacustrine and postglacial lake infill and support the interpretation of sub-bottom sonar record.
Computer applications to medicine. Medical informatics, Science (General)
Ahmed Bani Mustafa, Ahmed K. Abbas, Mortadha Alsaba
et al.
Abstract The prediction of the drilling rate of penetration (ROP) is one of the key aspects of drilling optimization due to its significant role in reducing expensive drilling costs. Many variables could affect ROP, which can be classified into two general categories; controllable operational variables and uncontrollable or environmental variables. Minimizing the drilling cost can be achieved through optimizing the controllable drilling parameters. As a direct result, the drilling speed will be increased while maintaining safe practices. The primary purpose of this study is to address the simultaneous impact of controllable parameters such as weight on bit (WOB), revolutions per minute, and flow rate (FR) on the rate of penetration (ROP). Response surface methodology was applied to develop a mathematical relation between operational controllable drilling parameters and ROP. To accomplish this, actual field datasets from several wells drilled in Southern Iraq in different fields were used. The second purpose of this study was to identify all prospective optimal ranges of these controllable parameters to obtain superior drilling performance with an optimum ROP. The obtained results showed that the developed model offers a cost-effective tool for determining the maximum ROP as a function of controllable parameters with reasonable accuracy. In addition, the proposed model was used to estimate optimal combinations of controllable drilling parameters for various depths. The results have shown that FR has the most significant effect on ROP variation with a sum of squares values of 23.47. Applying high WOB does not permanently improve ROP but could result in reducing ROP for some cases. The developed mechanical specific energy model for polycrystalline diamond compact (PDC) bit with vertical and deviated wells can estimate combinations of controllable drilling parameters. The developed model can be successfully applied to predict and optimize the drilling rate when using PDC bits, hence reducing the drilling time and the associated drilling cost for future wells.
Abstract Geomechanical modelling and simulation are introduced to accurately determine the combined effects of hydrocarbon production and changes in rock properties due to geomechanical effects. The reservoir geomechanical model is concerned with stress-related issues and rock failure in compression, shear, and tension induced by reservoir pore pressure changes due to reservoir depletion. In this paper, a rock mechanical model is constructed in geomechanical mode, and reservoir geomechanics simulations are run for a carbonate gas reservoir. The study begins with assessment of the data, construction of 1D rock mechanical models along the well trajectory, the generation of a 3D mechanical earth model, and running a 4D geomechanical simulation using a two-way coupling simulation method, followed by results analysis. A dual porosity/permeability model is coupled with a 3D geomechanical model, and iterative two-way coupling simulation is performed to understand the changes in effective stress dynamics with the decrease in reservoir pressure due to production, and therefore to identify the changes in dual-continuum media conductivity to fluid flow and field ultimate recovery. The results of analysis show an observed effect on reservoir flow behaviour of a 4% decrease in gas ultimate recovery and considerable changes in matrix contribution and fracture properties, with the geomechanical effects on the matrix visibly decreasing the gas production potential, and the effect on the natural fracture contribution is limited on gas inflow. Generally, this could be due to slip flow of gas at the media walls of micro-extension fractures, and the flow contribution and fracture conductivity is quite sufficient for the volume that the matrixes feed the fractures. Also, the geomechanical simulation results show the stability of existing faults, emphasizing that the loading on the fault is too low to induce fault slip to create fracturing, and enhanced permeability provides efficient conduit for reservoir fluid flow in reservoirs characterized by natural fractures.
Tina Coolman, David Alexander, Rean Maharaj
et al.
Abstract The economy of Trinidad and Tobago which mainly relies on its energy sector is facing significant challenges due to declining crude oil production in a low commodity price environment. The need for enhanced oil recovery (EOR) methods to meet the current and future energy demands is urgent. Studies on the use of polymer flooding in Trinidad and Tobago are limited, especially in terms of necessary data concerning the characterization of the adsorption of polymer flooding chemicals such as xanthan gum and aquagel polymers on different soil types in Trinidad and the viscosity characteristics of the polymer flooding solutions which affect the key attributes of displacement and sweep efficiency that are needed to predict recovery efficiency and the potential use of these flooding agents in a particular well. Adsorption and viscosity experiments were conducted using xanthan gum and aquagel on three different soil types, namely sand, Valencia clay (high iron) and Longdenville clay (low iron). Xanthan gum exhibited the lowest adsorption capacity for Valencia clay but absorbed most on sand at concentrations above 1000 ppm and Longdenville clay below 1000 ppm. At concentrations below 250 ppm, all three soil-type absorbent materials exhibited similar adsorption capacities. Aquagel was more significantly absorbed on the three soil types compared to xanthan gum. The lowest adsorption capacity was observed for Valencia clay at concentration levels above 500 ppm; however, the clay had the highest adsorption capacity below this level. Sand had the highest adsorption capacity for aquagel at concentrations above 500 ppm while Longdenville clay was the lowest absorbent above 500 ppm. Generally, all three soil types had a similar adsorption capacity for xanthan gum at a concentration level of 250 ppm and for aquagel at a concentration level of 500 ppm. The results offered conclusive evidence demonstrating the importance that the pore structure characteristics of soil that may be present in oil wells on its adsorption characteristics and efficiency. Xanthan gum polymer concentration of 2000 ppm, 1000 ppm and 250 ppm showed viscosities of 125 cp, 63 cp and 42 cp, respectively. Aquagel polymer concentrations of 2000 ppm, 1000 ppm and 250 ppm showed viscosities of 63 cp, 42 cp and 21 cp, respectively. Aquagel polymer solutions were found to generally have lower viscosities than the xanthan gum polymer solutions at the same concentration. Adsorption and viscosity data for the xanthan gum and aquagel polymers were incorporated within CMG numerical simulation models to determine the technical feasibility of implementing a polymer flood in the selected EOR 44 located in the Oropouche field in the southwest peninsula of the island of Trinidad. Overall, aquagel polymer flood resulted in a higher oil recovery of 0.06 STB compared to the xanthan gum polymer flood, so the better EOR method would be aquagel polymer flood. Additionally, both cases of polymer flooding resulted in higher levels of oil recovery compared to CO2 injection and waterflooding and therefore polymer flooding will have greater impact on the EOR 44 well oil recovery.
Taiwo Oludele Osunrinde, Iloka Chiamaka, Yawale Ahmad
Abstract Petroleum resources remain very important to the economic growth of several nations of the world even as oil price fluctuates in the current market today. The huge cost of exploration and exploitation of these resources makes it necessary for the attainment of high level of certainty in the methods adopted for its detection, quantification, planning and production. Mapping the right reservoir, understanding of reservoir characteristics most importantly; porosity, permeability, water saturation, thickness, and area extent of the reservoir, being able to reduce the uncertainties in these properties, making the right decision on when to inject water into the reservoir, where to locate these injectors and planning of where to drill new wells are very important factors that helps to determine the hydrocarbon reserves, cost of production and the degree of exploitation success rate and thus, needs to be treated with high level of certainty. This research work was, therefore, aimed at integrating several disciplines (Geologist, Reservoir Engineer, Well Engineer and Petroleum Economist) to carry out a detailed Field Development Plan (FDP) analysis for the reservoir in other to determine its success rate and economic viability. Simulations of three different cases of waterflood were analysed to decide the optimal development strategy to be applied to the field. Economic and sensitivity analyses were also carried out for all the cases suggested for the reservoir including the natural depletion case. Waterflood case 2 had NPV of $2,163,756,338 and the investment return of 47% and thus is recommended, since it is the best of all the cases.
Abstract In this communication, the impacts of adding SDS (sodium dodecyl sulfate), TBAF (tetra-n-butylammonium fluoride) and the mixture of SDS + TBAF on the main kinetic parameters of CO2 hydrate formation (induction time, the quantity and rate of gas uptake, and storage capacity) were investigated. The tests were performed under stirring conditions at T = 5 °C and P = 3.8 MPa in a 169 cm3 batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of 1–5 wt%, and the mixture of SDS + TBAF, would increase the storage capacity of CO2 hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO2 hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS + TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.
Abstract Seismic inversion involves extracting qualitative as well as quantitative information from seismic reflection data that can be analyzed to enhance geological and geophysical interpretation which is more subtle in a traditional seismic data interpretation. Among many approaches that have been made to improve interpretation of post-stack seismic data, a great effort has been made to use maximum likelihood (ML), sparse spike inversion (SSI) along with multi-attribute analysis (MAA) aimed to increase the resolution power of interpreting seismic reflection data and mapping into the subsurface lithology. These methods are applied to the Blackfoot seismic reflection data to estimate reservoir. The methods were first applied to the composite trace close to well locations and were inverted for acoustic impedance (AI). The results depict that the inverted AI matches very well with the well log AI. The statistical analysis demonstrates good performance of the algorithm. Thereafter, the entire seismic section was inverted to acoustic impedance section. The analysis of the inverted impedance section shows an anomaly zone in between 1060 and 1075 ms time and characterize it as reservoir. Further, the multi-attribute analysis is performed to estimate porosity and density in the inter-well region. The inverted porosity section shows a high porosity anomaly and a low density anomaly in between 1060 and 1075 ms time intervals which corroborated well with the low impedance zone and confirm the presence of a reservoir.
The Alishahi rhyodacitic-dacitic columnar joints are outcropped in the Middle-Upper Eocene Razak complex in the southeastern of Urumieh-Dokhtar volcanic belt in the Dehaj-Sarduieh volcano-sedimentary belt. The complex consists of intermittent of pyroclastic rocks, andesite, rhyolite, and rhyodacite-dacitic lava flows. The latter partially shows 5 to 6 unequal sided columnar structure in which entablature and colonnade sections along with stria are clearly visible. The predominant textures are phyritic, hyaloporphiritic, glomeroporphyritic, flow and sieve textures along with perlitic cracks. Mineralogically, the Alishahi rhyodacitic-dacitic rocks consist of plagioclase phenocrysts together with rare microphenocrysts of sanidine, orthoclase, hornblende, pyroxene, biotite and accessory minerals including apatite, titanite and opaques are setting in a cryptocrystalline glassy matrix. The matrix is partly in the verge of devitrification process and conversion to mixture of quartz and alkali feldspars. Geochemically, the Alishahi columnar joints are rhyodacitic-dacitic in composition with calc-alkaline nature. Negative Eu anomaly and decrease in Sr content along with increase in Si amount reveal the significance of plagioclase as a differentiated phase. Enrichment in large lithophile elements and depletion in high field strength elements normalized to primitive mantle such as Ti, Ta, Nb along with their chondrite normalized rare earth elements patterns are pointing to their magma formation in a volcanic arc setting in an active continental margin. The depletion in Nb and Ta could be related to their low solubility in aqueous fluids and melts formed under relatively low pressures in the shallow part of the subduction zone.
The Monti Lessini, a mountain group located north of the town of Verona, has been the scene of many different human adventures, some of them related to the local karst environment and features. In particular, during the Late Middle Ages, the Renaissance and the Modern Age, interesting undertakings linked with natural monuments and peculiarities of the karst environment, have involved famous people, cultural leaders of the time, as well as local inhabitants. Amongst celebrities there are hints that: 1) during the XIV century Dante Alighieri visited some karst cavities in the mountains, 2) during the XV century the famous painter Andrea Mantegna painted an image of the Ponte di Veja, a natural bridge, in the Camera degli Sposi of the Ducal Palace of Mantua. Of contemporary cultural leaders: 1) in the XVI century the pharmacist, Francesco Calceolari, created one of the first Wunderkammer in the world in Verona, an exhibition of curious objects collected in the mountains, 2) in 1739 the local priest, Gregorio Piccoli, began a description of paleontological cave fillings, proposed an interesting and in some respects modern interpretation of the geological history of the mountains. The local inhabitants of the mountain have been able not only to solve some of the environmental problems caused by the scarcity of surface water, but also to exploit some of the unusual resources such as ice trapped in caves. They also developed a system of producing ice and of storing it in cylindrical warehouses inspired by the local karst shafts. They understood aspects of the functioning of the karst geosystem, including underground karst hydrology and the dynamics of the epikarstic zone. Thus, here in the Lessini existence of the epikarst was understood by simple people long before the modern researchers.
Key Words: Man and karst, understanding of the karst environment, exploitation of natural resources, Monti Lessini, Venetian Prealps, Italy.
Fadwa Jroundi, Mara Schiro, Encarnación Ruiz-Agudo
et al.
Salt weathering enhanced by global warming and environmental pollution is increasingly threatening stone monuments and artworks. Here, the authors present a bacterial self-inoculation approach with indigenous carbonatogenic bacteria and find that this technique consolidates and protects salt damaged stone.
Na podlagi izsledkov starejših raziskav je bil zahodni del pogorja Mecsek vključen v naravni park Donava - Drava. Zato je bilo treba raziskati tudi prsti in rastlinstvo. Raziskave prsti so bile usmerjene predvsem v določanje pH in merjenje vsebnosti kalcija. To je pomembno za nadaljnje raziskave o vsebnosti težkih kovin v prsti. Vegetacijske raziskave so obsegale vodno bilanco, reakcijo prsti in njihovo kategorizacijo z vidika varstva narave. Posredni človekov vpliv na to kraško ozemlje se kaže v splošnem zniževanju pH. To pa je manjše v vrtačah, ker imajo te prsti razmeroma visoko vsebnost kalcija. Pravilnost zaščite tega kraškega območja opravičujejo rastlinske združbe z visokim deležem zaščitenih vrst med spremljajočimi vrstami. Raziskave potrjujejo, da je nujno ohraniti sedanje stanje, za kar pa je potrebna ustrezna zaščita.
Earlier studies on the karst in Western Mecsek have already shown that this area is worth protection due to its quite well preserved natural state. In consequence, declaring the karstic territory with its wider environment as a protected area is being considered in the Danube-Drava Natural Park. In order to prove the almost untouched natural state of an area good starting point is to examine its soil and flora. Soil studies focus on determining the pH, detecting any tendency of a shift towards lower pH values and on examining the carbonate content. In the future measurements to check the heavy metal content that are especially suitable for showing the levels of anthropogenic contamination will be added to these studies. Investigations on the flora based on the examination of water balance, soil reaction and determination of the rank according to the categories of nature conservation value offer a support to the claim of being protected. The results show that indirect anthropogenic effects can be detected by the pH shift towards lower values, but the same tendency of turning acidic is less characteristic in dolines which are the most sensitive points of karstic fields. However, the relatively high carbonate content favours the resistance against felling pH values. Examining the vegetation, and paying special attention to the ranking into nature conservation categories, a significantly high ratio of association - forming and accompanying species and the presence of protected species in relatively high numbers can be seen that proves the nature conserving feature of the territory. On the basis of the investigations carried out the maintenance of the present state of the territory is a desirable objective and in order to realize it the protection of the area is absolutely justified.
Prispevek obravnava pleistocensko morfogenezo doline Pod Košuto, ki je bila eno od območij detajlnega preučevanja pleistocenske morfogeneze porečja Tržiške Bistrice. Dolina izkazuje ledeniško preoblikovanje, genetsko problematično pa se je izkazalo karbonatno gradivo, ki se v večjem obsegu pojavlja na desni strani doline. S pomočjo litološke analize gradiva, meritev zaobljenosti gradiva ter z meritvami drobnih kraških denudacijskih oblik – mikrožlebičev ocenjujemo obdobje odložitve gradiva na sedanjem, sekundarnem mestu
The paper presents the Pleistocene morphogenesis research in the valley Pod Košuto. The area was one of the detailed studies in the wider research of the Pleistocene morphogenesis in Tržiška Bistrica river basin. Ice movements infl uenced the formation of valley Pod Košuto, but the research deals more with the genesis of the carbonate material that fi lls the right side of the valley. Researching the lithologic characteristics of the material, the measurements of particle roundness and with the help of the minor karst landforms measurements we offer the new view of the material deposition in the secondary – present location.
Abstract 12-Tungstophosphoric acid (PW) supported on KSF montmorillonite, PW/KSF, was used as catalyst for deep oxidative desulfurization (ODS) of mixed thiophenic compounds in model oil and crude oil under mild conditions using hydrogen peroxide (H2O2) as an oxidizing agent. A one-factor-at-a-time method was applied for optimizing the parameters such as temperature, reaction time, amount of catalyst, type of extractant and oxidant-to-sulfur compounds (S-compounds) molar ratio. The corresponding products can be easily removed from the model oil by using ethanol as the best extractant. The results showed high catalytic activity of PW/KSF in the oxidative removal of dibenzothiophene (DBT) and mixed thiophenic model oil under atmospheric pressure at 75 °C in a biphasic system. To investigate the oxidation and adsorption effects of crude oil composition on ODS, the effects of cyclohexene, 1,7-octadiene and o-xylene with different concentrations were studied.
The relationship between quartz surface textural defects (derived from weathering and diagenesis), palaeo-depositional environment and reservoir quality were studied using Tertiary outcrop rock samples obtained from the Belait and Lambir formations of the Sarawak Basin, Malaysia. Thin sections were used for mineral identification and to make observations regarding grain size and texture. Morphological characterization of the samples was performed using scanning electron microscopy (SEM) attached with energy-dispersive X-ray spectrometry (EDX) system, to show variations in quartz surface texture. The SEM images of Belait conglomerates reveal euhedral quartz crystals characterized with prominent mechanical weathering defects (such as straight and conchoidal fractures and striations). Conversely, the analysis of the Lambir sandstones identified chemical weathering features (such as chemical etchings, pitting, solution pits and notches). On the basis of petrology, SEM and CT scan images, evaluation results of reservoir quality indicate that the Lambir Formation in this study area is high-energy coast deposit, with apparent tide-dominated features; while Belait Formation is neritic-delta deposit, with obvious wave-dominated features; reservoir quality of the Belait Formation and Lambir Formation are poor, but the porosity of the Belait Formation is relatively higher than that of the Lambir Formation. Key words: Sarawak Basin, quartz morphology, scanning electron microscopy (SEM), microtextures, paleo-depositional environment, reservoir quality