Analysis of the composition and properties of heavy oils in situ by Low Field NMR relaxation method

For the analysis of heavy oils, the method of simultaneous measurement of the free induction decay (FID) together with the decay of the echo signal in the Carr-Purcell-Meiboom-Gill (CPMG) pulse program was used. The measurements were carried out on a «Chromatek-Proton 20M» NMR analyzer operating at a frequency of 20 MHz. A special control program was created on the NMR analyzer that automatically tunes and measures the full FID curve, then switches to measuring the decay of the echo amplitude by the CPMG pulse sequence, and then the investigation ends with a joint processing of all the experimental data. This method makes it possible to measure the amplitudes of NMR signals and the relaxation times T2 of protons of heavy oil components in situ, including asphaltenes, without any perturbations in the analyzed system. Under the influence of paramagnetic centers located in asphaltenes, the amplitude-relaxation characteristics of oil protons are divided into 7 groups associated with solid asphaltenes in crystalline and amorphous states, resins with high and low density, aromatic and saturated compounds. The NMR amplitudes of these fractions correlate well with the group composition of heavy oils as determined by gravitational-chromatographic SARA method. The combined FID + CPMG method can be recommended for determining the SARA composition and other properties of oil in situ. The behavior of fractions of heavy oil in the temperature range (-15оС ÷ +60оС) was investigated by SARA-NMR method. For the first time in situ, it has been shown that resins participate in the formation of asphaltenes in a closed volume when the oil is cooled from a stable state at room temperature, and vice versa, asphaltenes are disaggregated by heating with the release of resins. The SARA-NMR method is promising for the on-line monitoring of the production, transportation and processing of heavy oil in real conditions of temperature, pressure and dissolved gases. However, the design of the NMR sensor must be adapted to industrial applications. The possibilities of designing NMR probes on process pipelines of larger diameter than in laboratory instruments can be extended taking into account the procedure proposed for correcting the inhomogeneity of the magnetic field in the probed volume based on the FID signal of the liquid oil fraction

Dolomitic Calcretes from the Changhsignian (Upper Permian) Red Beds of the Orenburg Cis-Urals, Russia

The dolomitic calcrete profiles from the Boyevaya Gora and Tuyembetka sections, both represented by the uppermost Permian (Changhsignian) red continental deposits from the Orenburg Cis-Urals, were studied by sedimentological, mineralogical, and geochemical methods. Calcrete from the Boyevaya Gora section formed on sandy-silty flat alluvial fan/sheetflood sediments, under the setting of slow subsidence of the territory. Calcrete from the Tuyembetka section developed on relatively elevated mudflat/playa under a stable tectonic regime. The subtropical semi-arid climate was reconstructed based on the geochemical indices from the illuvial paleosol horizons. The presence of anhydrite in the calcrete profiles indicates the saline conditions of soil waters. Cryprocrystalline idiomorphic grains (1-3 μm) and the low Mn2+ partitioning ratio between the Ca- and Mg-position in dolomite (0.7-1.8) suggest its primary origin and a rapid crystallization from the soil waters. Free organic radicals and phosphorus-associated anion centers in the pedogenic dolomite identified by the electron paramagnetic resonance (EPR) analysis assume a biogenic contribution to the formation of dolomite. Fossilized fungal hyphae and bacteriomorphs along with the fragments of plant roots were detected by scanning electron microscopy (SEM) in both calcretes. The bacterial origin of dolomite from the studied calcretes was discussed

Dolomitic calcretes from the Changhsignian (Upper Permian) red beds of the Orenburg Cis-Urals, Russia

The dolomitic calcrete profiles from the Boyevaya Gora and Tuyembetka sections, both represented by the uppermost Permian (Changhsignian) red continental deposits from the Orenburg Cis-Urals, were studied by sedimentological, mineralogical, and geochemical methods. Сalcrete from the Boyevaya Gora section formed on sandy-silty flat alluvial fan/sheetflood sediments, under the setting of slow subsidence of the territory. Calcrete from the Tuyembetka section developed on relatively elevated mudflat/playa under a stable tectonic regime. The subtropical semi-arid climate was reconstructed based on the geochemical indices from the illuvial paleosol horizons. The presence of anhydrite in the calcrete profiles indicates the saline conditions of soil waters. Cryprocrystalline idiomorphic grains (1–3 μm) and the low Mn2+ partitioning ratio between the Ca- and Mg-position in dolomite (0.7–1.8) suggest its primary origin and a rapid crystallization from the soil waters. Free organic radicals and phosphorus-associated anion centers in the pedogenic dolomite identified by the electron paramagnetic resonance (EPR) analysis assume a biogenic contribution to the formation of dolomite. Fossilized fungal hyphae and bacteriomorphs along with the fragments of plant roots were detected by scanning electron microscopy (SEM) in both calcretes. The bacterial origin of dolomite from the studied calcretes was discussed

Transformation of Organic Matter of Domanik Rock from the Romashkino Oilfield in Sub- and Supercritical Water

© 2020, Pleiades Publishing, Ltd. Abstract: The transformation of the organic matter (OM) of low-permeable carbon-rich domanik rock of the Romashkino oilfield in sub- and supercritical water (SCW) at temperatures of 320, 374, and 420°C and pressures of 17, 24.6, and 24.4 MPa in a neutral medium has been studied. The original rock with a TOC content of 7% has a high oil generation potential and a low productivity index. The productivity index increases with an increase in the severity of the thermal treatment of the rock, which is due to intense kerogen degradation resulting in the formation of free hydrocarbons that are easy to recover from the rock. In rock extracts, in comparison with the original rock, the amount of saturated and aromatic hydrocarbons increases by more than two times and that of resin–asphaltene substances decreases. Distinctive features of the yields and compositions of rock extracts depending on the temperature of the experiments have been revealed. The highest yield of the extract was observed in the experiment with subcritical water at 320°C and associated with the degradation of resins and more complete extraction of asphaltenes and high-molecular-weight n-alkanes from the rock. Treatment in SCW at 374 and 420°C leads to intensive degradation of the kerogen structure involving the detachment of aliphatic chains from large fragments of kerogen and asphaltene macromolecules to form lower n-alkanes and carbon-rich substances, such as carbenes and carboids. The structure of asphaltenes becomes more condensed and oxidized in the SCW medium at 420°С, leading to a decrease in their paramagnetic properties. Using the EPR technique, the features of hyperfine splitting of the vanadyl complex line on 14N nitrogen nuclei have been revealed in the spectrum of asphaltenes of the SCW experiment at 420°С, indicating specific changes in their structure

Processing of High-Paraffinic vacuum residues by thermocatalytic methods to obtain bitumen

This work was conducted to discover ways of processing high-paraffin oil residues using thermochemical processes to obtain binders. The principal purpose of such treatment of high-paraffinic residues is in the thermocatalytic process which consists of dehydroesterification via oxidation of paraffins which increase bitumen's low-temperature stability (Fraass breaking point). Thus the n-alkanes, via our thermocatalytic process, can form several carbonyl compounds and oxidised compounds (such as alcohols, carboxylic acids, etc.). The thermocatalytic process of petroleum's raw materials in our research carried out in two stages, including the catalytic process, as well as the thermal oxidation by air-blowing process. In this study, we used a biturox reactor. We evaluated the content of paraffin with GOST 33139 and low-field nuclear magnetic resonance (1H LF-NMR) relaxometry in high-paraffinic vacuum residues, and after our thermocatalytic process in the obtained product. Moreover, in order to ensure the reliability of results obtained through the processing of vacuum residues as well as the obtained product, various physicochemical methods were used. These investigation methods include SARA fractionation, Fourier-transform infrared spectroscopy, electron paramagnetic resonance (EPR), and VNII NP analysis. Furthermore, the colloidal structures were studied using the Gaestel and Asphaltene Index. The tests were carried out to determine the bitumen's quality under the Russian interstate standard GOST 33133-2014 and the European standard EN 12591

The role of the leading formations of crystalline basement in the generation of clay minerals of weathering crust (East of the Russian plate)

© 2020 IOP Publishing Ltd. All rights reserved. The studied weathering crust on the basement rocks of the central part of the Volga-Ural anteclise lies at great depths under thick sediments of sedimentary cover. A diversity of initial basement rocks, features of formation and secondary changing processes of weathering crust determine interest for this geological formation and its uniqueness. Clay minerals play a major role in the composition of the weathering crust and determine its features. A change in the associations of clay minerals by the weathering profile allows distinguishing different zones, which confirm the zonal structure of this formation

Dispersed organic matter in the rocks of fluid seals according to magnetic radiospectroscopy

© 2020 IOP Publishing Ltd. All rights reserved. The purpose of this work is to use methods of magnetic radiospectroscopy - electron paramagnetic resonance (EPR) and low-field nuclear magnetic resonance (NMR LF) to determine the quality of the rocks of fluid seals of "lingul clays" (depth 82-102 m) of the Ashalchinskoye field, combining traditional methods of studying the properties of the material composition of rocks and dispersed organic matter in them. The heterogeneity of the mineral composition by the distribution of the EPR signal intensity of the ion Mn2+ has been established; it is mostly dense carbonate in the upper part, below it passes into the magnesian calcareous and ends with the clay part. Mineral heterogeneity is consistent with an increase in pore space in the middle and lower parts of the section. The EPR spectra of impurity ions in the structure of carbonate minerals, impurity ions Fe3+ in the structure of silicon compounds and the E'-center line in quartz control the state of the rock mineral matrix. The EPR signal of free radicals Corg characterizes the presence of organic matter. The presence of an insoluble part of organic matter, or the ability to generate hydrocarbons, is recorded by the newly formed radical C350 after isothermal annealing of the rock at a temperature of 350°C

УСПЕШНОСТЬ БИОУПРАВЛЕНИЯ ПАРАМЕТРАМИ ВАРИАБЕЛЬНОСТИ СЕРДЕЧНОГО РИТМА У ЛИЦ С РАЗЛИЧНЫМ УРОВНЕМ АРТЕРИАЛЬНОГО ДАВЛЕНИЯ

Objective. The aim was to determine the nature of cardiovascular reactions during a single session of heart rate variability (HRV) biofeedback in order to increase vagal effects on heart rhythm in patients with different initial levels of blood pressure (BP). Participants and methods. 33 people with normal blood pressure (group I), 20 people with uncorrected arterial hypertension (AH) grade 1-2 (group II) and 22 people with AH grade 1-2 taking antihypertensive drugs (group III) were observed. The parameters of heart rate variability (HRV), BP and pulse oximetry in the initial stage, during a single HRV biofeedback session and after this session in order to increase the total power of the HRV spectrum (each stage was 5 min). Results. In patients of group II low success of HRV biofeedback session, a high sympathetic reactivity and reduced oxygen blood saturation were determined. A reactivity of vagal mechanism is more pronounced in persons of group III than in those of group II. It is reflected in a significant increase in their total power of the HRV spectrum compared to the initial values and in uptrend saturation levels during the biofeedback session. Conclusions. The ability to HRV biofeedback in order to increase the total power of the HRV spectrum for standard short recording (5 min) can be seen as a test to determine the safety reserves of vagal autonomic cardiovascular regulation in persons with increased blood pressure. Цель исследования: определить характер сердечно-сосудистых реакций в процессе однократного сеанса биоуправления с целью усиления вагусных влияний на ритм сердца у лиц с различным исходным уровнем артериального давления (АД). Пациенты и методы. Обследовано 33 человека с нормальным АД (группа I), 20 человек с некорригированной артериальной гипертензией (АГ) 1–2 степени (группа II) и 22 человека с АГ 1–2 степени, принимающих антигипертензивные препараты (группа III). Регистрировали показатели вариабельности сердечного ритма (ВСР), АД и  пульсоксиметрии в фоне, во время однократного сеанса и после сеанса биоуправления с целью повышения суммарной мощности спектра ВСР (этапы по 5 мин). Результаты.  У лиц группы II выявлена низкая успешность биоуправления параметрами ВСР на фоне высокой симпатической реактивности и снижения сатурации крови. У лиц группы III реактивность вагусных механизмов более выражена, чем у лиц группы II, что отражено в значимом повышении у них суммарной мощности спектра ВСР по сравнению с фоном и в тенденции к повышению сатурации крови во время сеанса биоуправления. Выводы. Способность к биоуправлению параметрами ритма сердца с целью повышения суммарной мощности спектра ВСР в течение стандартной короткой записи (5 мин) может рассматриваться как тест для определения сохранности вагусных резервов вегетативной регуляции сердечной деятельности у лиц с повышенным АД.

EPR study of hydrocarbon generation potential of organic rich domanik rocks

The objects of investigation were samples of domanik formation rocks of Berezovskaya area of Romashkinskoye oil field. Content of Mn2+, SO3−, SO2− ions, vanadyl-ions and free radicals has been estimated with the X-band (9.43 GHz) electron paramagnetic resonance (EPR) spectroscopy. Composition of rock and extracted from it bitumen has been studied with methods of thermal analysis, X-ray-structural analysis and gas chromatography. Significant differences in mineralogical composition and content of organic matter were revealed in samples taken from adjacent intervals. Pyrolytic experiments have been conducted to simulate kerogen maturation and petroleum generation. The increasing number of free radicals was registered in all samples after pyrolysis in a hydrogen atmosphere at 350°C. A new organic free radical C350 was registered after pyrolysis. It is suggested that domanik source rocks have not fully realized their hydrocarbon generation potential

Phase state of an organic matter for NMR relaxation in low fields of rocks of the Bazhenov suite (Western Siberia)

© 2020 IOP Publishing Ltd. All rights reserved. The work of many researchers is devoted to studying the problem of the features of the formation of the Bazhenov suite and organic matter. Various methods are used to study the type and state of organic matter, despite this, the problem associated with the phase state and type of organic matter in these deposits, the methods for studying those remains relevant. One of these methods is the NMR relaxation method in low fields. For the analysis of heavy oils, the method of simultaneous measurement of the free induction decay (FID) together with the decay of the echo signal in the Carr-Purcell-Meiboom-Gill (CPMG) pulse program was used. We studied the decay form of relaxation curves and their approximation by a mathematical model adequate for solid, liquid, and gaseous states of matter, which contains information on the geochemical and petrophysical properties of organic matter, as part of a single reservoir, including both the mineral part and the fluid part