scholarly journals An integrated analysis of mineralogical and microstructural characteristics and petrophysical properties of carbonate rocks in the lower Indus Basin, Pakistan

2019 ◽  
Vol 11 (1) ◽  
pp. 1151-1167
Author(s):  
Waheed Ali Abro ◽  
Abdul Majeed Shar ◽  
Kun Sang Lee ◽  
Asad Ali Narejo

Abstract Carbonate rocks are believed to be proven hydrocarbon reservoirs and are found in various basins of Pakistan including Lower Indus Basin. The carbonate rock intervals of the Jakkher Group from Paleocene to Oligocene age are distributed in south-western part of Lower Indus Basin of Pakistan. However, there are limited published petrophysical data sets on these carbonate rocks and are essential for field development and risk reduction. To fill this knowledge gap, this study is mainly established to collect the comprehensive high quality data sets on petrophysical properties of carbonate rocks along with their mineralogy and microstructure. Additionally, the study assesses the impact of diagenesis on quality of the unconventional tight carbonate resources. Experimental techniques include Scanning Electronic Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and X-ray diffraction (XRD), photomicrography, Helium porosity and steady state gas permeability. Results revealed that the porosity was in range of 2.12 to 8.5% with an average value of 4.5% and the permeability was ranging from 0.013 to 5.8mD. Thin section study, SEM-EDS, and XRD analyses revealed that the samples mostly contain carbon (C), calcium (Ca), and magnesium (Mg) as dominant elemental components.The main carbonate components observed were calcite, dolomite, micrite, Ferron mud, bioclasts and intermixes of clay minerals and cementing materials. The analysis shows that: 1) the permeability and porosity cross plot, the permeability and slippage factor values cross plots appears to be scattered, which showed weaker correlation that was the reflection of carbonate rock heterogeneity. 2) The permeability and clay mineralogy cross plots have resulted in poor correlation in these carbonate samples. 3) Several diagenetic processes had influenced the quality of carbonates of Jakkher Group, such as pore dissolution, calcification, cementation, and compaction. 4) Reservoir quality was mainly affected by inter-mixing of clay, cementation, presence of micrite muds, grain compactions, and overburden stresses that all lead these carbonate reservoirs to ultra-tight reservoirs and are considered to be of very poor quality. 5) SEM and thin section observations shows incidence of micro-fractures and pore dissolution tended to improve reservoir quality.

2017 ◽  
Vol 35 (1) ◽  
Author(s):  
Mábia Ruana Silva de Sena ◽  
José Agnelo Soares

ABSTRACT. The construction of digital models from a set of x-ray tomography images of high resolution (μCT) acquired in rock samples is an innovative technique in growing use nowadays. The objectives of this study were: demonstrate the potential of this technique to quantify mineral content of 15 carbonate rock samples from northeastern Brazil, through μCT analysis; to compare the results with the analysis of X-ray diffraction (XRD); and to evaluate the effect of this mineral composition on the petrophysical properties of these rocks. The results achieved in the simulation of the mineral composition confirmed that the analyzed carbonate rock samples are mainly composed of calcite and or dolomite. In general the XRD results confirmed the mineral composition indicated by μCT, except for amorphous minerals and those with small contents (accessory minerals). The results show the content of major minerals controlling the petrophysical properties, especially grain density and elastic velocities. However, other factors which were assessed through the analysis of μCT, also significantly affected the elastic velocities: porosity, type of porosity (if intergranular or vugular) and proportion of microporosity present in the rock. Keywords: carbonates, microcomputed tomography, mineral characterization, petrophysics, x-ray diffraction. RESUMO. A construção de modelos digitais de rochas a partir de um conjunto de imagens de tomografia de raios de x de alta resolução (μCT) é uma técnica inovadora com uso crescente atualmente. Os objetivos deste estudo são demonstrar o potencial desta técnica para quantificar a composição mineral de quinze amostras de rochas carbonáticas oriundas de bacias sedimentares do nordeste brasileiro, através da análise dos dados de μCT, comparar os resultados com as análises de difração de raios x (DRX), e avaliar o efeito da composição mineral sobre as propriedades petrofísicas dessas rochas. Os resultados obtidos na simulação da composição mineral, através de μCT, indicam que as amostras são compostas principalmente por calcita e/ou dolomita. Em geral os resultados de DRX confirmaram a composição mineral indicada por μCT, exceto para minerais amorfos e para aqueles que apresentam pequenos teores (minerais acessórios). Os resultados demonstram que os minerais principais (com teores mais elevados) controlam as propriedades petrofísicas, especialmente a densidade de grãos e as velocidades elásticas. Entretanto, outros fatores, os quais foram avaliados através da análise de μCT, também afetaram de maneira significativa as velocidades elásticas: porosidade, tipo de porosidade (se intergranular ou vugular) e proporção de microporosidade presente na rocha. Palavras-chave: carbonatos, microtomografia de raios x, caracterização mineral, petrofísica, difração de raios x.


2019 ◽  
Vol 9 (4) ◽  
pp. 89-106
Author(s):  
Ali Duair Jaafar ◽  
Dr. Medhat E. Nasser

Buzurgan field in the most cases regards important Iraqi oilfield, and Mishrif Formation is the main producing reservoir in this field, the necessary of so modern geophysical studies is necessity for description and interpret the petrophysical properties in this field. Formation evaluation has been carried out for Mishrif Formation of the Buzurgan oilfield depending on logs data. The available logs data were digitized by using Neuralog software. A computer processed interpretation (CPI) was done for each one of the studied wells from south and north domes using Techlog software V2015.3 in which the porosity, water saturation, and shale content were calculated. And they show that MB21 reservoir unit has the highest thickness, which ranges between (69) m in north dome to (83) m in south dome, and the highest porosity, between (0.06 - 0.16) in the north dome to (0.05 -0.21) in the south dome. The water saturation of this unit ranges between (25% -60%) in MB21 of north dome. It also appeared that the water saturation in the unit MB21 of south dome has the low value, which is between (16% - 25%). From correlation, the thickness of reservoir unit MB21 increases towards the south dome, while the thickness of the uppermost barrier of Mishrif Formation increases towards the north dome. The reservoir unit MB21 was divided into 9 layers due to its large thickness and its important petrophysical characterization. The distribution of petro physical properties (porosity and water saturation) has shown that MB 21 has good reservoir properties.


2020 ◽  
pp. 084653712094167
Author(s):  
Scott J. Adams ◽  
Robert D. E. Henderson ◽  
Xin Yi ◽  
Paul Babyn

Artificial intelligence (AI) presents a key opportunity for radiologists to improve quality of care and enhance the value of radiology in patient care and population health. The potential opportunity of AI to aid in triage and interpretation of conventional radiographs (X-ray images) is particularly significant, as radiographs are the most common imaging examinations performed in most radiology departments. Substantial progress has been made in the past few years in the development of AI algorithms for analysis of chest and musculoskeletal (MSK) radiographs, with deep learning now the dominant approach for image analysis. Large public and proprietary image data sets have been compiled and have aided the development of AI algorithms for analysis of radiographs, many of which demonstrate accuracy equivalent to radiologists for specific, focused tasks. This article describes (1) the basis for the development of AI solutions for radiograph analysis, (2) current AI solutions to aid in the triage and interpretation of chest radiographs and MSK radiographs, (3) opportunities for AI to aid in noninterpretive tasks related to radiographs, and (4) considerations for radiology practices selecting AI solutions for radiograph analysis and integrating them into existing IT systems. Although comprehensive AI solutions across modalities have yet to be developed, institutions can begin to select and integrate focused solutions which increase efficiency, increase quality and patient safety, and add value for their patients.


1991 ◽  
Vol 35 (A) ◽  
pp. 333-340 ◽  
Author(s):  
W.N. Schreiner ◽  
R. Jenkins ◽  
P.F. Dismore

During the course of the past ten years the International Centre for Diffraction Data has sponsored a number of “Round Robin” tests to evaluate the quality of experimental X-ray diffraction data [1-5]. The latest of this series, called the Instrument Parameter Round Robin, was designed to evaluate, among other things, relative angularly-dependent sensitivity differences between diffractometers. Previous experiments have indicated that even perfectly aligned diffractometers of the same generic type, do not necessarily give the same set of relative intensities. One objective of the round robin was to quantify the magnitude of the experimental differences between data sets, and to demonstrate a means for external calibration of diffractometers, so that digitized diffraction intensity data obtained from different instruments could be directly compared.


2019 ◽  
Vol 34 (S1) ◽  
pp. S59-S70 ◽  
Author(s):  
Ekaterina Fomina ◽  
Evgeniy Kozlov ◽  
Svetlana Ivashevskaja

This paper presents an example of comparing geochemical and mineralogical data by means of the statistical analysis of the X-ray diffraction patterns and the chemical compositions of bulk samples. The proposed methodology was tested on samples of metasomatic rocks from two geologically different objects. Its application allows us to mathematically identify all the main, secondary and some accessory minerals, to qualitatively estimate the contents of these minerals, as well as to assess their effect on the distribution of all petrogenic and investigated trace elements in a short period of time at the earliest stages of the research. We found that the interpretation of the results is significantly influenced by the number of samples studied and the quality of diffractograms.


2018 ◽  
Vol 51 (4) ◽  
pp. 1094-1101 ◽  
Author(s):  
Yunchen Wang ◽  
Taimin Yang ◽  
Hongyi Xu ◽  
Xiaodong Zou ◽  
Wei Wan

The continuous rotation electron diffraction (cRED) method has the capability of providing fast three-dimensional electron diffraction data collection on existing and future transmission electron microscopes; unknown structures could be potentially solved and refined using cRED data collected from nano- and submicrometre-sized crystals. However, structure refinements of cRED data using SHELXL often lead to relatively high R1 values when compared with those refined against single-crystal X-ray diffraction data. It is therefore necessary to analyse the quality of the structural models refined against cRED data. In this work, multiple cRED data sets collected from different crystals of an oxofluoride (FeSeO3F) and a zeolite (ZSM-5) with known structures are used to assess the data consistency and quality and, more importantly, the accuracy of the structural models refined against these data sets. An evaluation of the precision and consistency of the cRED data by examination of the statistics obtained from the data processing software DIALS is presented. It is shown that, despite the high R1 values caused by dynamical scattering and other factors, the refined atomic positions obtained from the cRED data collected for different crystals are consistent with those of the reference models refined against single-crystal X-ray diffraction data. The results serve as a reference for the quality of the cRED data and the achievable accuracy of the structural parameters.


2015 ◽  
Vol 71 (11) ◽  
pp. 2328-2343 ◽  
Author(s):  
Ulrich Zander ◽  
Gleb Bourenkov ◽  
Alexander N. Popov ◽  
Daniele de Sanctis ◽  
Olof Svensson ◽  
...  

Here, an automated procedure is described to identify the positions of many cryocooled crystals mounted on the same sample holder, to rapidly predict and rank their relative diffraction strengths and to collect partial X-ray diffraction data sets from as many of the crystals as desired. Subsequent hierarchical cluster analysis then allows the best combination of partial data sets, optimizing the quality of the final data set obtained. The results of applying the method developed to various systems and scenarios including the compilation of a complete data set from tiny crystals of the membrane protein bacteriorhodopsin and the collection of data sets for successful structure determination using the single-wavelength anomalous dispersion technique are also presented.


Fuel ◽  
2022 ◽  
Vol 309 ◽  
pp. 122192
Author(s):  
Muhammad Ali ◽  
Abdul Majeed Shar ◽  
Aftab Ahmed Mahesar ◽  
Ahmed Al-Yaseri ◽  
Nurudeen Yekeen ◽  
...  

Author(s):  
Waqar Ahmad ◽  
Zafar Iqbal Shams ◽  
Haq Nawaz Abbasi ◽  
Muhammad Afzal Farooq ◽  
Muhammad Usama Zafar ◽  
...  

This study was conducted to assess the water quality of the lower Indus Basin, Pakistan. Eighty- two water samples were collected from forty-one locations of lower Indus Basin (Kashmore to Keti-Bander) during pre and post monsoon seasons. The variation pattern in the water quality has been observed in both seasons. The samples were analysed for physical quality (temperature, pH, turbidity, dissolved oxygen, total dissolved solids, salinity and conductivity), chemical quality (chloride, total alkalinity, total hardness, sulphate, potassium, sodium, iron, zinc, lead, mercury, copper, cadmium and nitrate) and biological quality (coliform bacteria). The study reveals that the concentrations of lead, mercury, and cadmium in water samples during both seasons were slightly higher than the permissible limits, whereas, all other parameters were within WHO guidelines. The higher concentration of heavy metals must be rectified by the concerned authorities in order to protect human health.  


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