The Petrography,Mineralogy, and Hydrocarbon Potential of the Shales of the Duwi Formation,Abu Tartur,South Western Desert,Egypt

Abstract

Eight shale samples related to the Duwi Formation (Campanian-Maastrichtian) of the Abu Tartur mines of the southwestern desert of Egypt were petrographically, mineralogically, and geochemically studied. The study results indicate that the detrital material of these shales were derived mainly from mafic to ultramafic components of the basement rocks under intensive chemical weathering and deposited in an alkaline reducing marine environment of low energy and these shales do not attain the requirements of hydrocarbon production.     

Bulk Compositions,Genetic Origin,Classifications, and Maturation of Crude Oils in the Gulf of Suez,Egypt

Abstract

API gravity, sulfur content, gas chromatography, and gas chromatography-mass spectrometry analyses were carried out for eight oil samples collected from different wells in the Gulf of Suez. The results showed that two types of oils could be recognized: (a) heavy oils, which are oils from Zafarana, Rahmi, West Bakr, and Ras Gharib wells, are of low maturation and originated mainly from terrestrial organic sources; and (b) light oils, which are oils from Um El Yuser, Ras El Ush, Gemsa-SE, and Hurghada wells, have a high level of maturation and orginate mainly from marine organic sources.     

Origin, migration, and accumulation of carbon dioxide in the East Changde Gas Field, Songliao Basin, northeastern China

CO₂ reservoirs are widely distributed within the Yingcheng Formation in the Songliao Basin, but the extreme horizontal heterogeneity of CO₂ content causes difficulties in the exploration and exploitation of methane. Former studies have fully covered the lithology, structure, and distribution of the reservoirs high in CO₂ content, but few are reported about migration and accumulation of CO₂. Using the East Changde Gas Field as an example, we studied the accumulation mechanisms of CO₂ gas. Two original types of accumulation model are proposed in this study. The fault-controlled accumulation model refers to gas accumulation in the reservoir body that is cut by a basement fault (the West Xu Fault), allowing the hydrocarbon gas generated in the lower formation to migrate into the reservoir body through the fault, which results in a relatively lower CO₂ content. The volcanic conduit-controlled accumulation model refers to a reservoir body that is not cut by the basement fault, which prevents the hydrocarbon gas from being mixed in and leads to higher CO₂ contents. This conclusion provides useful theories for prediction of CO₂ distribution in similar basins and reservoirs.     

A New Approach for Accurate Prediction of the Phase Behavior of the Complex Mixtures of Acid Gases,Hydrocarbons, Water,and Methanol in the Petroleum Industry

In this work a new approach for accurate prediction of the vapor-liquid equilibrium of the complex mixtures of water, methanol, acid gases (H₂S, CO₂), and hydrocarbons considering the hydrogen bonding association, hydrolytic dissociation, and acid gas solvation effects is presented. The overall average absolute deviation between the predicted and measured compositions regarding 330 sour gas mixtures is about 3.22%. The proposed CPA/electrolyte model is quite reliable over wide ranges of temperatures and sour gas concentrations and can be employed for accurate design of sour natural treatment and flow assurance systems in oil and gas industries.     

Hydrocarbon accumulation characteristics of beach-bar sandstones in the southern slope of the Dongying Sag, Jiyang Depression, Bohai Bay Basin, China

A number of beach-bar sandstone reservoir beds are developed in the upper fourth member of the Eocene Shahejie Formation （Es4s） on the southern slope of the Dongying Sag.Based on the analysis of seismic and logging data,with characterization and petrographic studies of core and cutting samples,this paper analyzes the hydrocarbon accumulation characteristics in two typical blocks of the Boxing and Wangjiagang oilfields,especially reservoir bed heterogeneity and migration conditions that influence oil and gas distribution,calculates the index of reservoir bed quality （IRQ） with a mathematical method,and discusses the relationship between driving force and resistance of hydrocarbon accumulation.Taking into account the characteristics of thin interbeds in beach-bar sandstones,an experimental model simulated the characteristics of hydrocarbon migration and accumulation in thin interbedded sandstones with reservoir bed heterogeneity.The results showed that hydrocarbon distribution and properties were extremely non-uniform.Reservoir bed and migration conditions controlled hydrocarbon accumulation in beach-bar sandstones.IRQ is above 0.4 in the main hydrocarbon region.Sand body distribution,structural configuration and fault systems controlled the direction of regional migration and location of hydrocarbon accumulation.Simulation experiments indicated that the change of driving force for hydrocarbon migration affected selective accumulation mechanisms.Hydrocarbon moved vertically along fault zones to the reservoir and resulted in the distribution of hydrocarbon in the reservoir.Two kinds of hydrocarbon accumulation models exist in the study area.One is a hydrocarbon accumulation model controlled by reservoir bed heterogeneity and the second is a hydrocarbon accumulation model controlled by a complex migration system with faults connecting sandbodies.Finally,different exploration strategies should be adopted for the detailed exploration for beach-bar sandstone reservoirs according to different geological backgrounds.     

Stratigraphy,Petrography, and Petrophysical Properties of the Subsurface Upper Cretaceous Sediments,Northwestern Desert,Egypt

Abstract

In this article, 33 core samples and 160 ditch samples of Upper Cretaceous age were studied at different depths from Horus well 1. Stratigraphic, petrographic, and petrophysical studies and well log analysis are used to study and evaluate the rock units. The studied core samples are dolomite (Abu Roash formation), shaly limestone, and argillaceous sandstone (Bahariya formation). The depositional environments of the studied rock units vary from deltaic to deltaic-marine. The effective porosity of the studied core samples is low and may be of secondary origin. The upper part of low Bahariya is considered a high category of reservoir. The stratigraphic significance of some benthonic foraminifera (Thomasinella, Nezzazata, and Nezzatine) furnishes new information on the age determination. Cenomanian-Santonian time is suggested for the studied interval (Bahariya and Abu Roash formations).     

Effect of the nature,shape, and size of crystals on the activity and stability of pentasils

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 2, pp. 22–24, February, 1992.     

Water content,water activity,water structure and the stability of foodstuffs

Determination of water content, whatever the accuracy of the analytical method, is not sufficiently informative in relation to the stability of the investigated food product. Water activity (a_w) brings a supplement of information as it accounts for the availability of water for degradation reactions.The understanding of why certain products are more stable than others at the same a_w needs an elucidation of water structure. Of particular importance are the interactions (hydrophilic, hydrophobic) between water and the components of the foodstuff and the effect of the soluble molecules of the food on the hydrogen bonding in solvent water.Studying water in foods should start with an anlytical determination of water content for commercial and legal reasons which are evident. This has to be completed with the measurement of the thermodynamic activity of water in the food. Such a parameter (a_w) should hold an important place in the identification of the food product, especially as regards its shelf life. A further step in unveiling the behaviour of water in foods consists in determining water molecules in the molecules in the studied food matrix.The tripartite (analytical, thermodynamical and structural) approach to water in foods will be examined based on examples of sugars and sugar rich products.     

Origin of shale gas in the Triassic Yanchang Formation,Ordos Basin,China

The Chang 7 Member shale gas of the Upper Triassic Yanchang Formation, Ordos Basin, is a representative of continental shale gas in China. The Chang 7 shale is currently in the oil window, suggesting it should primarily be producing oil, but an exploratory well found high levels of gas production. In addition, the methane carbon isotopic composition (δ¹³C₁) of Chang 7 shale gas is generally depleted in ¹³C relative to that calculated by Ro, according to the δ¹³C-Ro equation. It is uncertain whether Chang 7 shale gas has mixed with biogenic gas or early thermogenic gas. In this study, over 100 samples of fresh shale cores were collected from the Yanchang Formation, and on-site gas desorption experiments and experimental analysis were carried out. Measured shale gas content was considerable, and was found to be proportional to the abundance of organic matter. Through comprehensive evaluation of the gas composition and δ¹³C₁, it was concluded that there was no biogenic gas contribution to the shale gas in the study area. The negative δ¹³C₁ of shale gas was due to the different formation mechanisms of shale gas and conventional natural gas. Methane in shale gas reservoirs is the result of methane accumulation at all stages, which increases the shale gas content.     

Effect of pressure,temperature, and mass fraction of CO2 on the state of the resin in crude oil

This paper focus on the main influence factors (temperature, pressure, and mass fraction of CO₂) on the state of resin in the crude oil during CO₂ flooding by using a visualization method. The state of resin is not affected by the variation of the temperature. Only when the pressure is increased to a certain value, the state of resin can be affected by the variation of the pressure. During the variation of the mass fraction of CO₂, the state of the resin has a significant change, including the growth out of nothing, expansion from small to large, and transformation from a adsorbed solid to a flowable liquid. During the actual application process of CO₂ flooding in oilfield, the influence of the temperature can be ignored, the appropriate mass fraction of CO₂ is below 30% and the gas injection pressure should maintain a relatively low value. The results can provide a theoretical basis to avoid the resin aggregation during CO₂ flooding.     

Effect of pressure,temperature, and mass fraction of CO2 on the stability of the asphaltene constituents in crude oil

This paper focus on the main influence factors (temperature, pressure, and mass fraction of CO₂) on the state of asphaltene in the crude oil during CO₂ flooding by using high temperature and high pressure microanalysis system of solid precipitation. For the simulated oil sample – CO₂ system, the state of asphaltene is not affected by temperature within this range of 50°C to 100°C, the particle size of the asphaltene has an increase with the increase of the pressure from 8MPa to 40 MPa. When the mass fraction of CO₂ is less than 35%, the state of the asphaltene has not changed and the asphaltene particles are in a suspension state. When the mass fraction of CO₂ increases to 40%, the aggregation of the asphaltenes occurs and then form precipitation. With the further increase of the mass fraction of CO₂, the particle of the asphaltene aggregates has a significant increase. For the field development project design of CO₂ flooding, the influence of the temperature can be ignored, the appropriate mass fraction of CO₂ is below 35% and the gas injection pressure should maintain a relatively low value. The results can provide a theoretical basis to avoid the asphaltene precipitation during CO₂ flooding.     

Source Rock Characteristics,Organic Maturity,and Hydrocarbon Potential of the Lower Paleozoic Sequences in the Taurus Belt of Turkey

Abstract

Like elsewhere in the world, Lower Paleozoic (Cambrian-Ordovician-Silurian) formations in Turkey are also exposed in limited areas. Lower Paleozoic sequences are exposed at various parts of the Taurus belt in southern Turkey. In this study, organic matter content, type, and maturity of organic matter and their hydrocarbon potential were investigated. In addition, the Lower Paleozoic is very restricted with respect to species and their diversity. Therefore, it is very important to investigate type and content of organic matter within the Lower Paleozoic sediments. In general, total organic carbon (TOC) values of Lower Paleozoic sequences are extremely low. TOC could not be measured in Cambrian, Ovac?k, and Çaltepe limestones. Shales in the Emirgazi region have very low TOC values. Ordovician and Silurian units also have low TOC values. Total organic carbon in these sequences is residual carbon. In the S ₂-TOK kerogen diagram, all organic materials are plotted in the Type III kerogen field. All samples were composed dominantly of residual organic matter and lesser amounts of Type III kerogen. According to T _max values, the Cambrian, Ordovician, and Silurian formations are over maturity character. In addition, these sequences have very low S ₁, S ₂, and HI values.     

A new method for the simultaneous and highly sensitive determination of the total content of F-, Cl-, Br-, and S-organic compounds in products of oil refining

A new method for the simultaneous determination of the total content of fluorine-, chlorine-, and sulfur-containing organic compounds in products of oil refining is proposed. The method is based on the high-temperature oxidation of a sample in a flow of oxygen, the absorption of conversion products, and the analysis of the total absorbate in isocratic conditions by the ion chromatography method for the content of anions that correspond to the analytes. The detection limit for the total content of Cl-, Br-, and S-organic compounds in a sample of 1 μl is 10⁻⁵%; for F-containing compounds, it is 10⁻⁶%. The results of the analysis of samples of aviation kerosene and gasoline for the total content of F-, Cl-, Br-, and S-organic compounds are presented.     

Geochemical characteristics of the Permian Changxing Formation reef dolomites, northeastern Sichuan Basin, China

The recent discovery of deep and ultra-deep gas reservoirs in the Permian Changxing Formation reefs, northeastern Sichuan Basin is a significant development in marine carbonate oil & gas exploration in China. Reef dolomites and their origins have been major research topics for sedimentologists and oil & gas geologists. The petrography, trace element and isotope geochemistry of the reef dolomites indicated that the dolomites are characterized by low Sr and Mn contents, relatively low Fe contents, very similar δ 13 C and δ 18 O values and very different 87 Sr/ 86 Sr ratios. Although the calculated results of the fluid mixing suggested that a mixture with 85%-95% meteoric water and 5%-15% seawater seemed to be the dolomitizing fluids of the reef dolomites, the low Mn contents, relatively low Fe contents, high δ 13 C values and high homogenization temperatures of the dolomites did not support that there were large proportions of meteoric water in the dolomitization process, and the 87 Sr/ 86 Sr ratios which were close to coeval seawater also did not support the possibility of the mixture of deep-burial circulated fluids from clastic rocks. High temperature deep-burial circulated seawater with low Mn and Fe contents, high Sr content and high δ 13 C values from the dissolution of widely distributed Triassic evaporites during the burial diagenetic processes (including dehydration of water-bearing evaporites) could have been the dolomitizing fluids of the reef dolomites.     

Study of the products of benzene transformation in the presence of argon,hydrogen, and propane-butane mixture in barrier discharge

The conversion of benzene in a medium of Ar, H₂, and propane-butane mixture in a dielectric-barrier discharge reactor, accompanied by polymerization yielding liquid and solid compounds, has been investigated. The amount of polymerization products reaches 79.7 wt %. Addition of H₂ to benzene reduces the amount of benzene-soluble polymer-like compounds in the products to ∼61 wt % and precludes the formation of solid polymerization products. The transformation of benzene with a propane-butane mixture yields alkylbenzenes (up to 38.5 wt %) and liquid alkanes (to 20.5 wt %, mainly with a branched structure). It has been found that an increase in benzene flow rate from 0.08 to 0.4 cm³/min in the case of benzene conversion with the propane-butane mixture can significantly reduce the amount of polymerization products from 56.7 to 9.1 wt %.     

Geochemical studies of the Silurian oil reservoir in the Well Shun-9 prospect area, Tarim Basin, NW China

Commercial oil flow has been obtained from the sandstone reservoir of the Lower Silurian Kelpintag Formation in the Well Shun-9 prospect area.In the present studies,10 Silurian oil and oil sand samples from six wells in the area were analyzed for their molecular and carbon isotopic compositions,oil alteration（biodegradation）,oil source rock correlation and oil reservoir filling direction.All the Silurian oils and oil sands are characterized by low Pr/Ph and C21/C23 tricyclic terpane（〈1.0） ratios,＂V＂-pattern C27-C29 steranes distribution,low C28-sterane and triaromatic dinosterane abundances and light δ13C values,which can be correlated well with the carbonate source rock of the O3 l Lianglitage Formation.Different oil biodegradation levels have also been confirmed for the different oils/oil sands intervals.With the S1k2 seal,oils and oil sands from the S1k1 interval of the Kelpintag Formation have only suffered light biodegradation as confirmed by the presence of ＂UCM＂ and absence of 25-norhopanes,whereas the S1k3-1 oil sands were heavily biodegraded（proved by the presence of 25-norhopanes） due to the lack of the S1k2 seal,which suggests a significant role of the S1k2 seal in the protection of the Silurian oil reservoir.Based on the Ts/（Ts＋Tm） and 4-/1-MDBT ratios as reservoir filling tracers,a general oil filling direction from NW to SE has been also estimated for the Silurian oil reservoir in the Well Shun-9 prospect area.     

Listeria monocytogenes in ready-to-eat,sliced, cooked ham and salami products,marketed in the city of São Paulo,Brazil: Occurrence,quantification, and serotyping

The preference for ready-to-eat sliced foods may pose an increased risk for food-borne diseases, and a major concern is the presence of Listeria monocytogenes. L. monocytogenes was assessed in two types of products: cooked ham and salami. One hundred and thirty samples of each product were acquired in retail shops in the city of São Paulo and submitted to laboratory analysis. The rate of positives was significantly higher in salami samples than in ham samples (6.2% and 0.8%, respectively). L. monocytogenes counts in salami samples varied between <10 and 1900 colony-forming units per gram (CFU/g). The serotypes found in both products were as follows, according to incidence: 4b (37.5%), 1/2b (25%), 3b (25%), and 1/2c (12.5%). Based on the results of the present study, the authors suggest that the risk of listeriosis resulting from the consumption of salami is higher than that associated with the consumption of cooked ham.     

Effects of gamma irradiation on the microbiological,nutritional, and sensory properties of fresh vegetable juice

The radiation pasteurization process was performed to improve the microbiological quality of fresh vegetable juice. Carrot and kale juice were irradiated and their microbiological, nutritional, and sensory properties were evaluated. The contaminating bacteria in the juices before irradiation ranged from 10⁶ to 10⁷ CFU/ml. All the aerobic and coliform bacteria in the carrot juice were eliminated by irradiation at a dose of 3 kGy, whereas about 10² CFU/ml of the bacteria survived in the kale juice irradiated at up to 5 kGy. However, the cells that survived from irradiation in the kale juice did not grow, whereas those of the non-irradiated samples reached 10⁹ CFU/ml after 3 days of storage at 10 °C. Amino acids were stable at up to 5 kGy of an irradiation. Radiation resulted in a dose-dependent reduction of the ascorbic acid content. However, the contents of the total ascorbic acid, including dehydroascorbic acid, were stable at up to 3 kGy of an irradiation. The sensory evaluation results immediately after irradiation were not different in any of the samples. At a 3-day storage, the sensory quality of the irradiated juice was adequate, while the quality of the non-irradiated control was deteriorated.     

塔里木盆地麦盖提斜坡奥陶系风化壳成藏条件

基于地震、钻井资料综合研究,分析塔里木盆地麦盖提斜坡及其周缘古隆起背景上奥陶系风化壳特征及其储集层发育主控因素,探讨该区油气分布规律与勘探方向。区域构造成图与构造解析表明,麦盖提斜坡及其周缘发育塔里木盆地最大规模的奥陶系碳酸盐岩风化壳,与上覆志留系/石炭系泥岩形成优质储盖组合。奥陶系碳酸盐岩历经多期大型岩溶作用,以受古岩溶地貌、构造作用与岩性控制的小型缝洞体储集层为主。已有钻探多位于北部岩溶缓坡—洼地,岩溶作用较弱、充填严重,据古地貌分析与储集层预测,南部岩溶斜坡区储集层应更发育。构造演化与生烃演化史综合分析表明,碳酸盐岩古隆起演化与变迁控制了油气的运聚与分布,具有晚海西期成油、喜马拉雅晚期调整与原油裂解气再成藏的两期充注史。古隆起东西两端的玛南、麦西斜坡区长期位于油气聚集与调整的有利部位,具备形成大面积碳酸盐岩缝洞型岩性油气藏的地质条件,是塔里木盆地碳酸盐岩油气勘探的有利接替领域。