Charakterystyka utworów czerwonego spągowca w aspekcie badań rentgenowskiej mikrotomografii komputerowej i mikroskopii optycznej

Nafta-Gaz ◽  
2020 ◽  
Vol 76 (11) ◽  
pp. 765-773
Author(s):  
Marek Dohnalik ◽  
◽  
Konrad Ziemianin ◽  
Keyword(s):  
Pore Space ◽  
Mercury Porosimetry ◽  
Mineralogical Composition ◽  
Effective Porosity ◽  
Hydrocarbon Exploration ◽  
Core Material ◽  
Reservoir Properties ◽  
Average Value ◽  
Full Characterization ◽  
Single Well

The article presents the results of microtomographic and petrographic investigations of Rotliegend sandstones collected from core material from wells located in the area of the Fore-Sudetic Monocline in its central and northern parts and also on the border of the Fore-Sudetic Monocline and the Mogilno - Łódź Synclinorium. Three areas were selected for the study: Czarna Wieś–Parzęczewo (19 samples), Środa Wielkopolska–Kromolice (21 samples) and Siekierki–Miłosław (21 samples). The aim of the petrologic and microtomographic studies was to investigate how the different reservoir properties of sandstones will be reflected in the results of the methods used. Strong differences between samples from the region of Środa Wielkopolska–Kromolice and the other studied areas have been demonstrated. In the case of this area several key factors were noticed: the highest average value of effective porosity; the highest average content of pores belonging to class VII (pore volume subsystem classification); three times higher average value of the CT porosity coefficient and the largest length of the average chord. Also in terms of petrography (composition of grains, cement type) it is a region where major differences, especially compared to the region of Czarna Wieś–Parzęczewo, can be seen. Based on the obtained results, it was possible to rank the examined regions in terms of their reservoir properties – from the worst (Czarna Wieś–Parzęczewo) to the best (Środa Wielkopolska–Kromolice). These conclusions are also confirmed by other petrophysical analyses (eg. mercury porosimetry, permeability analysis). Combination of the obtained microtomographic and petrographic results allowed to obtain a full characterization of the investigated samples – both in terms of the mineralogical composition of grains, as well as the development of the pore space. These data, especially in combination with the results of density and porosity analyses (helium pycnometry and mercury porosimetry), open up a number of possibilities to carry out different types of modeling (porosity, permeability) both on the scale of the sample itself, as well as the scale of a single well or even the whole basin, which is crucial for creating a hydrocarbon exploration strategy.

scholarly journals Analysis of the core microstructure of terrigenic reservoirs based on lithological-petrographic studies to support the creation of digital core model

2020 ◽  
Vol 20 (1) ◽  
pp. 37-42
Author(s):  
IP Belozerov ◽  
MG Gubaidullin ◽  
AV Yuriev
Keyword(s):  
Pore Space ◽  
Core Model ◽  
Core Material ◽  
Berea Sandstone ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Digital Core ◽  
Northern Russia ◽  
Lithological Composition ◽  
Correct Understanding

The question of digital core modelling appears highly relevant due to the fact that there is not always a sufficient amount of core material available from studied wells: in some cases, it is not possible to select core material (in case of loose, weakly cemented rocks); in others, such material may be completely absent. In order to create a computer model of a digital core, it is necessary to have a correct understanding of the pore space microstructure and rock lithological composition and structure, among the most important features determining the quality of sedimentary reservoir rocks. Such information can be obtained by carrying out lithological-petrographic studies of thin sections of reference (standard) core samples. The aim of the present work is to study petrographic thin sections for their further use in creating a digital core model. The article discusses the methodology and results of laboratory lithological and petrographic studies of thin sections using the available core information. The paper presents the results of laboratory studies of thin sections of terrigenous sandstones obtained from the Berea Sandstone formation (USA). The choice of the Berea Sandstone is due to its wide recognition by specialists, as well as its homogeneity, both in terms of the grain size of constituent rocks and their filtration and reservoir properties. The work also presents the results of data analysis on lithological and petrographic studies of core material from the terrigenous deposits obtained in the Timan-Pechora province in northern Russia. The research results can be used for mathematical modelling of the pore space microstructure in a digital core model.

scholarly journals Lithofacial Zoning of Producing Horizons of Oil and Gas Fields Using Artificial Neural

2020 ◽  
pp. 96-105
Author(s):  
І. О. Fedak ◽  
Ya. М. Koval
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Oil And Gas ◽  
Pore Space ◽  
Development Project ◽  
Core Material ◽  
Geological Model ◽  
Reservoir Properties ◽  
Gas Field ◽  
Artificial Neural

The quality of an oil and gas field development project depends greatly on the accuracy of forecasting the processes that occur in the pore space of reservoirs during the extraction of hydrocarbons under certain technolo-gical conditions in production wells. The forecasting is possible if there is a geological model of the field. The more detailed the model is, the more accurate the prediction will be. The whole amount of information used to create a geological model of a field is of discrete nature, and its level of detail is determined by the number of wells that have discovered pay formations. One of the most important elements of the geological model is the nature of changes in reservoir properties of productive formations along their stretch and perpendicular to bedding. The creation of elements of this type requires information from laboratory studies of core material, interpretation of the wells logging results and methods for predicting the nature of changes in reservoir properties in the interwell space. The presence of these elements makes it possible to investigate the situation in which sedimentation (within the existing wells) took place and what types of facies the geological sections of the drilled producing intervals correspond to. Lithofacial zoning of the productive formation according to this information makes it possible to trace the regularities of distribution of facies of various types, to establish their mutual location, and accordingly to predict the nature of changes in reservoir properties in the interwell space. The lack of a sufficient amount of core material is a typical problem that makes it difficult to identify facies. There is another way to solve this problem – this is the identification of facies according to the morphology of logging curves. Nowadays, this problem is solved at a qualitative level. In this paper, it is proposed to apply a quantitative method for identifying facies using an artificial neural network. In particular, the morphology of curves is formalized by a number of parameters that form the input vector of an artificial neural network. At the output of the network, the clusters of logging curves with a similar morpho-logy are formed. The authors refer these clusters to a certain type of facies analytically. On the basis of the information obtained, lithofacial zoning of the productive formations is carried out.

scholarly journals Creation of high-conductive filtration channels in core samples when simulating acid exposure at a filtering unit

2021 ◽  
Vol 63 (5) ◽  
pp. 17-27
Author(s):  
K. A. Ravelev ◽  
K. A. Vyatkin ◽  
P. Yu. Ilyushin
Keyword(s):  
Hydrochloric Acid ◽  
Acid Treatment ◽  
Oil And Gas ◽  
Pore Space ◽  
Mineralogical Composition ◽  
Reservoir Properties ◽  
Research Attention ◽  
Core Samples ◽  
Bottom Hole ◽  
Hydrochloric Acid Treatment

Background. Hydrochloric acid treatment is currently one of the main methods used for recovering and improving the reservoir properties of bottom-hole formation zones. In the process of acid treatment, during the reaction of the acid composition and the rock, highly conductive filtration channels are formed. The structure and shape of such channels characterise the treatment efficiency. As a result, much research attention is currently paid to predicting the formation of filtration channels and changes in the filtration characteristics of reservoirs with different properties and types of pore space.Aim. To study the factors that directly affect the formation of dissolution channels in core samples when simulating hydrochloric acid treatment of the bottom-hole zone of carbonate reservoirs on a filtration unit. The main objectives are to determine the significance of these factors and to establish dependencies reflecting their effect on the efficiency of technologies aimed at stimulating oil inflow.Materials and methods. We used the results of filtration and X-ray tomographic studies on core samples taken from the scientific base of the “Geology and Development of Oil and Gas Fields” Scientific and Educational Centre. The collection of rock samples is represented by various deposits confined to the oil and gas complexes of the Perm Territory.Results. The conducted analysis allowed us to identify the effect of various factors on the formation of highly conductive filtration channels during acid treatment. These factors were found to include the lithological and mineralogical composition and initial filtration parameters of core samples, as well as the type of pore structure. Dependences that characterise the efficiency of acid treatment were determined.Conclusions. The obtained results can be used when developing measures for the intensification of oil production, taking into account the revealed factors.

scholarly journals The impact of diagenesis on the reservoir quality of the early Cretaceous Lower Goru sandstones in the Lower Indus Basin, Pakistan

2021 ◽  
Author(s):  
Qamar UZ Zaman Dar ◽  
Renhai Pu ◽  
Christopher Baiyegunhi ◽  
Ghulam Shabeer ◽  
Rana Imran Ali ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Pore Space ◽  
Hydrocarbon Exploration ◽  
Indus Basin ◽  
Coarse Grained ◽  
Rock Properties ◽  
Reservoir Properties ◽  
Diagenetic Processes ◽  
Lower Indus Basin ◽  
The Impact

AbstractThe sandstone units of the Early Cretaceous Lower Goru Formation are significant reservoir for gas, oil, and condensates in the Lower Indus Basin of Pakistan. Even though these sandstones are significant reservoir rocks for hydrocarbon exploration, the diagenetic controls on the reservoir properties of the sandstones are poorly documented. For effective exploration, production, and appraisal of a promising reservoir, the diagenesis and reservoir properties must be comprehensively analyzed first. For this study, core samples from depths of more than 3100 m from the KD-01 well within the central division of the basin have been studied. These sandstones were analyzed using petrographic, X-ray diffraction, and scanning electron microscopic analyses to unravel diagenetic impacts on reservoir properties of the sandstone. Medium to coarse-grained and well-sorted sandstone have been identified during petrographic study. The sandstone are categorized as arkose and lithic arkose. Principal diagenetic events which have resulted in changing the primary characters of the sandstones are compaction, cementation, dissolution, and mineral replacement. The observed diagenetic processes can be grouped into early, burial, and late diagenesis. Chlorite is the dominant diagenetic constituent that occurs as rims, coatings, and replacing grains. The early phase of coating of authigenic chlorite has preserved the primary porosity. The recrystallization of chlorite into chamosite has massively reduced the original pore space because of its bridging structure. The current study reveals that diagenetic processes have altered the original rock properties and reservoir characteristics of the Lower Goru sandstone. These preliminary outcomes of this study have great potential to improve the understanding of diagenetic process and their impact on reservoir properties of the Lower Goru sandstone in the Lower Indus Basin and adjoining areas.

GAS HAZARD ASSESSMENT IN THE RUDNA MINE, BASED ON ANALYSIS OF POROSITY OF DOLOMITES FROM THE RESERVOIR FORMATION

2017 ◽  
pp. 47-58
Author(s):  
Anna POSZYTEK ◽  
Robert Rożek ◽  
Lidia Dudek
Keyword(s):  
High Pressure ◽  
Pore Space ◽  
Mercury Porosimetry ◽  
Mining Industry ◽  
Effective Porosity ◽  
High Porosity ◽  
Closed Porosity ◽  
X Ray ◽  
Gas Hazard ◽  
Reservoir Potential

Reservoir dolomites saturated with gas under high pressure were found in the ceiling of excavations in a Rudna copper mine in southwestern Poland. Reservoir dolomites are a major concern in the mining industry and the focus of substantial research. High-porosity dolomites are definitively considered "hazardous", but the gas is extracted from the dolomites with low porosity, too. So, it is necessary to know way of gas occurrence in the pore space. This article aims to describe the reservoir potential of the dolomites through pore space characterisation and determine whether the gas can migrate into the excavations. A comprehensive analysis of the distribution of pore size and nature using microscopic observations, X-ray microtomography and mercury porosimetry. The results distinguished three types of dolomites with different porosities: dolomites with high effective porosity, dolomites with reduced effective porosity, and sealed dolomites. Particular attention should be paid to sealed dolomites. Their effective porosity results from mercury porosimetry are very low. However, they also contained 4% closed porosity described from microscopic observations, where gas is accumulated, too. Presence of gas in the closed pores dolomites is a common phenomenon. However, the presence of high-pressure gas traps within locally more porous, microcraced and permeable dolomites is a major threat.

scholarly journals Local radon flux maxima in the quaternary sediments of Schleswig–Holstein (Germany)

2021 ◽  
Author(s):  
Johannes Albert ◽  
Maximilian Schärf ◽  
Frieder Enzmann ◽  
Martin Waltl ◽  
Frank Sirocko
Keyword(s):  
Water Content ◽  
Pore Space ◽  
Mineralogical Composition ◽  
Fault System ◽  
Near Surface ◽  
Salt Diapirism ◽  
The North ◽  
Radon Flux ◽  
Published Evidence ◽  
Tectonically Active

AbstractThis paper presents radon flux profiles from four regions in Schleswig–Holstein (Northern Germany). Three of these regions are located over deep-rooted tectonic faults or salt diapirs and one is in an area without any tectonic or halokinetic activity, but with steep topography. Contrary to recently published studies on spatial patterns of soil radon gas concentration we measured flux of radon from soil into the atmosphere. All radon devices of each profile were deployed simultaneously to avoid inconsistencies due to strong diurnal variations of radon exhalation. To compare data from different seasons, values had to be normalized. Observed radon flux patterns are apparently related to the mineralogical composition of the Quaternary strata (particularly to the abundance of reddish granite and porphyry), and its grain size (with a flux maximum in well-sorted sand/silt). Minimum radon flux occurs above non-permeable, clay-rich soil layers. Small amounts of water content in the pore space increase radon flux, whereas excessive water content lessens it. Peak flux values, however, are observed over a deep-rooted fault system on the eastern side of Lake Plön, i.e., at the boundary of the Eastholstein Platform and the Eastholstein Trough. Furthermore, high radon flux values are observed in two regions associated with salt diapirism and near-surface halokinetic faults. These regions show frequent local radon flux maxima, which indicate that the uppermost strata above salt diapirs are very inhomogeneous. Deep-rooted increased permeability (effective radon flux depth) or just the boundaries between permeable and impermeable strata appear to concentrate radon flux. In summary, our radon flux profiles are in accordance with the published evidence of low radon concentrations in the “normal” soils of Schleswig–Holstein. However, very high values of radon flux are likely to occur at distinct locations near salt diapirism at depth, boundaries between permeable and impermeable strata, and finally at the tectonically active flanks of the North German Basin.

Basic Physical and Mechanical Properties of Composites Based on Three Different Cements

2016 ◽  
Vol 677 ◽  
pp. 186-190 ◽  
Author(s):  
Monika Čáchová ◽  
Eva Vejmelková ◽  
Kateřina Šestáková ◽  
Pavel Reiterman ◽  
Martin Keppert ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Open Porosity ◽  
Mercury Porosimetry ◽  
Physical And Mechanical Properties ◽  
Mineralogical Composition ◽  
Physical Parameters ◽  
Vacuum Saturation ◽  
Saturation Method ◽  
Properties Of Composites

This article is focused on cement based composites. Two cements differing in mineralogical composition are utilised as main binder in composites mixtures. Results of measured physical parameters of studied materials are presented. For the sake of comparison, a reference material with Portland cement was also prepared. Basic physical properties (measured by water vacuum saturation method and by helium pycnometry), characterizations of pore system (determined by mercury porosimetry) and mechanical properties are the matter of this study. Composites show various open porosity; the results of open porosity of materials containing special cements show higher values, in comparison with composite based on Portland cement. This fact of course influences other material characteristics - mainly mechanical properties.

Crystallization of simonkolleite (Zn5Cl2(OH)8 ∙ H2O) in powder samples prepared for mineral composition analysis by quantitative X-ray diffraction (QXRD)

Nafta-Gaz ◽  
2021 ◽  
Vol 77 (5) ◽  
pp. 293-298
Author(s):  
Urszula Zagórska ◽  
◽  
Sylwia Kowalska ◽  
Keyword(s):  
Quantitative Analysis ◽  
Internal Standard ◽  
Mineralogical Composition ◽  
Hydrocarbon Exploration ◽  
Composition Analysis ◽  
Internal Standard Method ◽  
X Ray Diffraction ◽  
Method Error ◽  
X Ray ◽  
Significant Difference

The analysis of mineralogical composition by quantitative X-ray diffraction (QXRD) is one of the standard research methods used in hydrocarbon exploration. In order to improve it and to obtain better results, the methodology of quantitative analysis used at Well Logging Department is being periodically (more or less) modified. After the introduction of the improvements, comparative analyses were performed on archival samples. Reflections from an unidentified phase which did not occur in the tested Rotliegend sandstone samples were noticed on X-ray diffractograms of archival samples. Reflections of a mineral called simonkolleite were identified in the X-ray diffraction database. Chemically it is a hydrated zinc chloride of the formula: Zn5Cl2(OH)8 × H2O. Analysis of the composition of samples in which simonkolleite crystallised, indicated that the mineral is being formed in the result of the slow reaction of zinc oxide with halite (NaCl) and water vapour. An attempt was made to determine the influence of the presence of this mineral on the results of the quantitative analysis of mineralogical composition. The above methodology was applied on a group of ten samples. The results of the quantitative analysis conducted for archival samples stored with added zincite standard containing simonkolleite and for new, freshly grinded (without artifact) samples were compared. The comparison of the obtained results showed a slight influence of this mineral on the quantitative composition of the remaining components. The difference between the results usually did not exceed the method error. At the same time a significant difference in the calculated content of the internal standard was noted – on average 1% less in archival than in new samples. This shows that the reaction occurring in the archival samples will affect the evaluation of the quality of the obtained quantitative analysis, at the same time excluding the possibility of determining the rock’s amorphous substance content with the internal standard method.

Depositional facies, diagenetic clay minerals and reservoir quality of Rotliegend sediments in the Southern Permian Basin (North Sea): a review

Clay Minerals ◽  
1982 ◽  
Vol 17 (1) ◽  
pp. 55-67 ◽  
Author(s):  
U. Seemann
Keyword(s):  
Clay Minerals ◽  
North Sea ◽  
Effective Porosity ◽  
Hydrocarbon Exploration ◽  
Reservoir Quality ◽  
Burial Diagenesis ◽  
Permian Basin ◽  
Northern Margin ◽  
The North

AbstractThe Southern Permian Basin of the North Sea represents an elongate E-W oriented depo-centre along the northern margin of the Variscan Mountains. During Rotliegend times, three roughly parallel facies belts of a Permian desert developed, these following the outline of the Variscan Mountains. These belts were, from south to north, the wadi facies, the dune and interdune facies, and the sabkha and desert lake facies. The bulk of the gas reservoirs of the Rotliegend occur in the aeolian dune sands. Their recognition, and the study of their geometry, is therefore important in hydrocarbon exploration. Equally important is the understanding of diagenesis, particularly of the diageneticaily-formed clay minerals, because they have an important influence on the reservoir quality of these sands. Clay minerals were introduced to the aeolian sands during or shortly after their deposition in the form of air-borne dust, which later formed thin clay films around the grains. During burial diagenesis, these clay films may have acted as crystallization nuclei for new clay minerals or for the transformation of existing ones. Depending on their crystallographic habit, the clay minerals can seriously affect the effective porosity and permeability of the sands.

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