Crude Oil Sources Research Articles

Naphtha Characterization (PIONA, Density, Distillation Curve and Sulfur Content): An Origin Comparison

Naphtha is an important distillation product of crude oil, and is used as a raw material for first-generation products such as ethylene, propylene, gasoline, xylene (BTX), and others. However, due to the different sources of crude oil, differences in naphtha composition impact the quality of conversion processes. Parameters such as pressure, charge flow, and temperature need to be adjusted for conversion efficiency. This work aims to compare naphtha samples from different origins, through the analysis of distillation curve (ASTM D86), density (ASTM D4052), total sulfur (ASTM D4294), and n-paraffins, iso-paraffins, olefins, naphthene, and aromatics (PIONA, ASTM D5134). Among these parameters evaluated in naphtha, the ones that showed the greatest correlation with the type of oil and its origin was the amount of total sulfur, number of aromatics, and paraffins. The three imported evaluated naphtha presented values greater than 200 mg/kg of total sulfur, aromatics above 9%w, and paraffins (P + I) below 76%w, while the national naphtha presented sulfur contents of at most 141 mg/kg, aromatics below 7%w, and paraffins (P + I) above 78%w. Finally, the study of this type of hydrocarbon enables the understanding of the needs of Latin American refineries and the world in relation to its treatment. National petrochemical companies have more difficulty in processing this product, causing an increase in naphtha importation by 108.51% from 2020/2021 in Brazil. Given this scenario, the Brazilian government should invest more in its petrochemical plants to reduce these imports, which, in the long term, would have a positive impact on the quality and value of naphtha byproducts.

Catalyst in algal refinery: A way towards production of high-quality biofuel

Microalgae are considered as the major resource to produce biofuel. However, among many microalgae it is essential to screen those which are robust in their growth and accumulate abundant lipid in their cells leading to the formation of biofuel upon transesterification. Among the microalgal species, diatoms are one of the richest sources of crude oil that have been fossilized under the ocean beds for thousands of years. There are many limitations for entry of such biofuel in the commercial market in different sector of biofuel dependent industries. However, high yield and low cost of production are among the two important factors while screening any microalgae for biofuel production. Therefore, catalyst constitute important ingredients during transesterification process of biofuel formation. These catalysts are both homogenous and heterogenous and need to be screened about their cost and availability for manufacturing economical biofuel on large scale consumption for a way towards green vehicles which has zero carbon footprint and pollution.

Comparative assessment of soil microbial community in crude oil contaminated sites

Petroleum refineries generate oily sludge that contains hazardous polycyclic aromatic hydrocarbons (PAH), and hence, its proper disposal is of foremost concern. Analysis of the physicochemical properties and functions of indigenous microbes of the contaminated sites are essential in deciding the strategy for bioremediation. This study analyses both parameters at two geographically distant sites, with different crude oil sources, and compares the metabolic capability of soil bacteria with reference to different contamination sources and the age of the contaminated site. The results indicate that organic carbon and total nitrogen derived from petroleum hydrocarbon negatively affect microbial diversity. Contamination levels vary widely on site, with levels of PAHs ranging from 5.04 to 1.66 × 103 μg kg−1 and 6.20 to 5.64 × 103 μg kg−1 in Assam and Gujarat sites respectively, covering a higher proportion of low molecular weight (LMW) PAHs (fluorene, phenanthrene, pyrene, and anthracene). Functional diversity values were observed to be positively correlated (p < 0.05) with acenaphthylene, fluorene, anthracene, and phenanthrene. Microbial diversity was the highest in fresh oily sludge which decreased upon storage, indicating that immediate bioremediation, soon after its generation, would be beneficial. Improvement in the bio-accessibility of hydrocarbon compounds by the treatment of biosurfactant produced by a (soil isolate/isolate) was demonstrated., with respect to substrate utilization.

Carbon isotopic compositions of mono-, di-, tri-aromatics provide insights into the source of sulfur-rich crude oils in the Huanghekou Depression, Bohai Bay Basin

The stable carbon isotope compositions (δ13C) of individual aromatic hydrocarbons have been analyzed in sulfur-rich and sulfur-lean crude oils from the Huanghekou depression, Bohai Bay Basin. The δ13C values of individual aromatic hydrocarbons, including alkylbenzenes, alkylnaphthalenes, alkylphenanthrenes, alkylfluorenes and alkyldibenzothiophenes, are reported. The main aims are to find out the origin of these oils and their relationship to paleoclimate. The distribution of aromatic hydrocarbons and maturity parameters show the oils all stay in the low-mature to mature stage. Meanwhile, aromatic hydrocarbons are mainly derived from the diagenetic/catagenetic origin. The δ13C values for 1,2,4-trimethylbenzene (−30.7‰ to −28.8‰) and 1,2,3,4-tetramethylbenzene (−32.4‰ to −26.3‰) indicate the algae-derived organic matter for alkylbenzenes. Some isomers, such as 1,7-+1,3-+1,6-dimethylnaphthalene, 1,2,5-trimethylnaphthalene, 1,2,5,6-+1,2,3,5-tetramethylnaphthalene, 1,10- + 1,3- + 3,10- + 3,9-dimethylphenanthrenes, 1,6- + 2,9- + 2,5- dimethylphenanthrenes and 4,9- + 4,10- + 1,9- dimethylphenanthrenes show isotopic depletion (−34.9‰ to −25.2‰), indicating the major contribution of algae for these compounds. Meanwhile, isotopically depleted (−33.6‰ to −26.7‰) alkyldibenzothiophenes represent the algae input. δ13C values for mainly algae-derived naphthalene to trimethylnaphthalenes of sulfur-rich oils are more enriched than those of sulfur-lean oil, with the most significant difference of 4.4‰, indicating that the aridity of the environment and stratified water column result in the enrichment in 13C.

The Geochemical Characteristics of Source Rock and Oil in the Fukang Sag, Junggar Basin, NW China

The Fukang Sag in the Junggar Basin is the main exploration block. However, the origin and source of crude oil are still controversial, which seriously affects the well locating and exploration in this area. In the present work, 30 source rocks and 21 crude oils were collected for geochemical analysis to clarify the source of the organic matter, the sedimentary environment, and the evolution degree. Among them, the source rocks of the Pingdiquan Formation are type II1 organic matter with good quality, the source rocks of the Badaowan Formation are type II2-III organic matter with fair–good quality, and the source rocks of the Xishanyao Formation are type II2 organic matter with fair quality. All source rocks are in the mature stage. The results of the biomarker compounds show that the lacustrine mudstone of the Xishanyao Formation and the coal-measure mudstone of the Badaowan Formation were deposited in reducing environments. The former was mainly from lower aquatic organisms, and the latter was from terrestrial higher plants. The mudstone of the Pingdiquan Formation was formed in a weakly oxidizing–weakly reducing depositional environment, and its parent material was of mixed origin. Based on the results of the biomarker compounds and carbon isotopes, the crude oils were divided into three categories. The Family I crude oil has the characteristics of low maturity, low salinity, and more input of low-level aquatic organisms, and the carbon isotope has a good affinity with the lacustrine mudstone of the Xishanyao Formation. The Family II crude oil shows medium maturity, low salinity, mainly higher plant input, and heavy carbon isotope, mainly derived from the Badaowan Formation coal-measure mudstone. The Family III crude oil is characterized by high maturity, high salinity, mixed parent materials, and light carbon isotope and originates from the mudstone of the Pingdiquan Formation. The results provide a reference for oil and gas exploration and development in the eastern area of the Junggar Basin; the future research will focus on well areas with high maturity near the Fukang fault zone.

Crude Oil Source and Accumulation Models for the Wenchang Formation, Southern Lufeng Sag, Pearl River Mouth Basin, (Offshore) China

In recent years, a large amount of industrial oil and gas resources have been discovered in the Paleogene Wenchang Formation (WC) of the southern Lufeng sag, confirming that the WC resources are promising prospects for petroleum exploration. However, because of the complex lithology, multiple sources of crude oil and multi-period charging characteristics in the WC, the accumulation process and model have not been clearly understood. Therefore, in this study, the main sources of crude oil and the process of hydrocarbon accumulation in key oil accumulation periods are determined by combining biomarker and geological analyses. Finally, the model of oil and gas accumulation is systematically summarized. The obtained results show that the source rock of the WC is the main source of hydrocarbons in the study area. The crude oil types in the southern Lufeng sag are classified into three types. Type A crude oil comes from source rocks of Wenchang Formation Members 3 and 4. Type B crude oil comes partly from source rocks of Wenchang Formation Members 1, 2, and 3 and partly from source rocks of Wenchang Formation Members 5 and 6. Type C crude oil is a mix of type A and type B crude oil. There are three accumulation periods that typify the study area: in the first period, accumulation was with vertical migration by fault; in the second period, accumulation was with lateral migration by sand body; and in the third period, accumulation was with vertical migration by sand body and adjacent to the source. The methodology and results of the accumulation process in southern Lufeng sag can support offshore oil and gas exploration.

Chemometric recognition of oil–source in the western the Ordos Basin, China

In recent years, significant breakthroughs in the exploration and development of tight oil in the Lower Triassic Yanchang Formation of the Ordos Basin have been achieved. However, there is still a lack of genetic relationship analysis of oil sources in this basin on a large scale. In this study, we performed Rock–Eval pyrolysis to analyze 41 source rocks in four study areas. A total of 79 crude oil and source rock samples from this region was analyzed using gas chromatography mass spectrometry to identify the geochemical characteristics of crude oil and source rocks. Based on 16 biomarker parameters, we used principal component analysis and multidimensional scaling for the analysis of the crude oil source. Combined with alternating least squares, we quantitatively calculated the contribution rate of source rocks to crude oil. The results indicated that the region can be divided into four types of oil sources: the Habahu area in the northwest of the basin, the Huanxian area in the west of the basin, the Pengyang area in the southwest of the basin, and the center of basin. The oil–source comparison results reveal that the reservoirs in the central basin are of single crude oil, whereas those in the Habahu, Huanxian, and Pengyang areas are mixed crude oil. Based on ALS, the relative contribution rates of source rocks in each area to different samples were determined. The present research provides us with a valuable method to use a variety of chemometrics methods to jointly judge the crude oil source and the classification of gene groups.

THE QUALITY OF CRUDE OIL FROM THE MUANDA FIELD AND ITS CONSEQUENCES ON THE INSTALLATIONS

"The study on the quality of the crude oil of the Muanda field and its consequences on the installations, was carried out within the framework of our scientific research of study of Advanced Diploma (DEA). The objective of this study was to determine upstream the physical properties and composition of the Muanda field crude oil, in order to determine the conditions of asphaltene deposits in the tubing and other installations. To achieve this, the samples collected in the field were analysed in our laboratories and at the PVT Laboratory of Sonangol in Luanda to constitute the results of this manuscript. The results of these analyses show that the crude oil of the Muanda field is a Medium Crude Oil (29.7°API) on the API density scale with the hypothesis of two sources: one of Light Oil, the other of Medium Oil). These two sources of crude oil, induce the establishment of two oils of different viscosities and pour points of which one more viscous (Mu 23) and the other less viscous (Mu 16 and Mu 2) having the average pour point at 15° C (60°F). The Standing correlation gave acceptable results and close to those of the Electromagnetic Viscometer (EMV). The chemical composition showed that the crude oil is composed of 18.63% of gas and 81.37 % of Paraffins and Asphaltenes, and that this oil is of low sulfur content type (Low Sulfur Content (LSC) &lt;0.6% weight). A solid sample collected from the oil field was characterized through melting, further heating and solidification point (28 oC). "

Targeted delivery of nanoparticles to a heterogeneous crude oil zone in an unsaturated porous medium

Targeted binding of nanoparticles to a heterogeneous crude oil source zone was evaluated. Nanoparticles preferentially attached to the crude oil, while their transport was significantly influenced by physical heterogeneity and water content.

Power of recycling waste cooking oil into biodiesel via green CaO-based eggshells/Ag heterogeneous nanocatalyst

The depletion of crude oil sources and a growing understanding of the adverse environmental effects of using fossil fuels promoted the development of alternative techniques to convert waste biomass into biofuels. Considering ecological safety and economic challenges, this work investigates the catalytic transesterification of waste cooking oil (WCO) for biodiesel production as a substitute for fossil fuels. Chicken eggshells were calcined at 900 °C to form CaO nanoparticles (NPs) and impregnated with Ag NPs solution prepared from fresh fenugreek leaf extract. Several characterization methods characterized the catalyst: FTIR, TEM, SEM, XRD, and zeta-potential/particle sizer, confirming the composite's spherical shape and mesoporous structure. The optimal transesterification conditions were achieved by performing batch reaction experiments. The biodiesel product was analyzed, and its fuel features (density and acid number, kinematic viscosity, cloud, and flash points) were determined and compared to standards. Confirmatory techniques (GC-FID, FTIR, 1H NMR, and 13C NMR) were also used to confirm the conversion of WCO into biodiesel. This study revealed the transformation of WCO into biodiesel with acceptable fuel features depending on the CaO/Ag catalyst's effectiveness as an excellent, safe commercial catalyst by its three times reusability with 90% biodiesel yield, ease of recovery, and cheap cost fabrication.

Correlation Analysis of Linear Viscoelastic (LVE) Properties, Damage Resistance and Microstructure of Unmodified Asphalt Binders with the Same Penetration Grade.

The penetration grade system is still widely adopted for selecting asphalt binder with desired paving performance. However, the initial material compositions of asphalt binder with the same penetration level are still different, and vary with the crude oil source and essentially result in different rheological performance. This study aimed to assess the linear viscoelastic (LVE) properties, and high- and intermediate-temperature and microscale characteristics of seven unmodified asphalt binders from different sources and countries with the same penetration level of 70. The LVE parameters were firstly evaluated followed by comparisons to various damage-based indexes. The microstructure of asphalt binders was further investigated followed by correlations between morphology and performance parameters. Experimental results indicate the |G*|/sin δ is well related to the MSCR-based non-recoverable creep compliance; furthermore, the R and |G*|·sin δ can generally represent the LAS-based failure strain and fatigue life, respectively. The viscoelastic nature of tested binders was clearly distinguished and related to rheological performance by atomic force microscopy (AFM). The roughness parameters and the phases' content derived from AFM images showed significant correlations with LVE characteristics and fatigue resistance nature, respectively. This research provides theoretical foundations for further investigating the rheological performance and microstructure characteristics, and their correlations with asphalt binders.

A novel wrinkled-leaf sesame mutant as a potential edible leafy vegetable rich in nutrients

Sesame (Sesamum indicum L.) is an ancient and globally important oil crop in the tropic and subtropic areas. Apart from being a good source of high-quality oil, sesame also represents a new source of edible leafy vegetables. However, data regarding the nutritional composition of the sesame leaves, especially their phytonutrient composition, are scarce. Previously we have developed a sesame mutant JQA with curly, wide, and thick leaves that are potentially used as a vegetable. The objective of this work was to gauge the nutrient contents in leaves of the JQA mutant by colorimetry methods. The sesame mutant JQA and its wild-type counterpart JQB were grown in the field, and leaf samples were collected at the flowering stage. Results showed that the sesame wrinkled leaves of JQA are a rich source of crude oil (5.33–6.38%), crude protein (3.14%), amino acids (> 18.6 mg/g), crude fiber (> 0.36%), cellulose or hemicellulose (> 21.4 mg/g), sugars (> 12.5 mg/g), vitamins, and flavones (> 63.2 mg/g). The wrinkled sesame leaves were high in unsaturated acid (32.0 mg/g), calcium (18.5 mg/g), potassium (16.1 mg/g), as well as vitamin B6 (24.5 mg/g), B2 (14.4 mg/g), C (1.7 mg/g) and D (1.3 mg/g) compared to other common green leafy vegetables. The fresh leaves had a mean total flavone content of 65.7 mg/g and can be consumed as fresh vegetables or preserved in a dry state. Collectively, the nutritional composition of the wrinkled leaf mutant JQA was ideal and thus had high RDIs (recommended daily intakes), suggesting that the wrinkled leaves are a rich source of nutrients and therefore suitable to be consumed as a new edible green vegetable.

Influence of free fatty acid content and degree of fat saturation in laying hen diets on egg quality, yolk fatty acid profile, and cholesterol content

The aim of the present study was to evaluate the effect of dietary free fatty acid (FFA) content and the degree of saturation on egg quality, yolk fatty acid (FA) profile, and yolk cholesterol content. For a 15-wk period, a total of 144 laying hens (19-wk-old) were randomly assigned to 8 treatments arranged in a 2×4 factorial design, with 2 sources of crude oil (soybean oil and palm oil) and 4 levels of FFA (10, 20, 30, and 45%). The dietary treatments were achieved by progressively substituting the original oils with equivalent amounts of their corresponding acid oils (soybean acid oil and palm fatty acid distillate, respectively). No differences in ADFI or egg mass were found. However, dietary FFA reduced egg production (linear, P < 0.05) and increased the feed conversion ratio (linear, P < 0.05). Higher levels of FFA in soybean diets resulted in higher egg weight with higher albumen and yolk weights (linear, P < 0.01). Palm diets presented higher yolk:albumen ratio than soybean diets (P < 0.001), but the effect of FFA did not follow a linear trend. Hens fed soybean diets laid eggs with higher Haugh units (HU) than palm diets (P < 0.001), although increasing the dietary FFA% reduced the HU values in both (linear, P < 0.001). Palm diets enhanced shell quality with greater resistance to breakage, and higher dry matter and ash content than soybean diets (P < 0.05). No differences in egg chemical composition and yolk cholesterol content were found (P > 0.05). The saturation degree had a significant effect on all the analyzed yolk FA (P < 0.001) except for arachidonic acid (C20:4 n-6), whereas increasing the FFA content did not affect to a great extent. These results show that varying dietary FFA level did not affect egg quality and yolk composition as much as the dietary fat source did, supporting the use of acid oils and fatty acid distillates as fat ingredients for feed.

Geochemical characteristics and sources of crude oil in the Wenchang B depression and the western Qionghai uplift of the Zhu-3 sub-basin, Pearl River Mouth Basin, south China sea

The Wenchang B depression and the western Qionghai uplift, in the south of the Zhu-3 sub-basin, are two adjacent sub-tectonic units with multiple oil-bearing structures. The former contains well-developed source rocks, whereas the latter does not. Previous studies have preliminarily explored the source of crude oil in the Wenchang B depression and the western Qionghai uplift. However, systematic investigations have been absent in characterizing the two main source rocks (i.e. Enping and Wenchang formations) and elucidating the migration of crude oil, which has significantly hindered oil and gas exploration. In this study, multiple methods are integrated to re-evaluate the source rocks of the depression, clarify crude oil sources, and analyse vertical oil migration and accumulation characteristics. The methods used included Rock-Eval pyrolysis, carbon isotope analysis, gas chromatography-mass spectrometry (GC-MS), hierarchical cluster analysis (HCA), and basin modelling. The source rocks of the Wenchang formation are demonstrated to have good to excellent hydrocarbon generation potential, whereas those of the Enping Formation have fair to good potential. Both source rocks are further divided into two members (i.e. EP1 and EP2 members for the Enping Formation and WC1 and WC2 members for the Wenchang Formation) based on differences in the biomarkers including ratios of bicadinanes (W + T)/C30hopane (C30H), ∑C30 4-methylsterane (MSt)/∑C29 regular sterane (RSt), pristane (Pr)/phytane (Ph), and ∑C27RSt/∑C29RSt, the source rocks are divided into four sets, named E1, E2 of the Enping Formation, and W1, W2 of the Wenchang Formation, respectively. Both W1 and W2 source rocks were weakly oxidizing-weakly reducing sedimentary environments. The input of organic matter to W2 source rock was dominated by aquatic organisms such as algae. The parent source of W1 source rock has both the contribution of aquatic organisms and the input of terrestrial organic matter. The E1 source rock was formed in an oxidative depositional environment, and its parent source is similar to that of W1. E2 source rock was a weakly oxidizing-weakly reducing depositional environment, and the parent source was resins from higher plants. There are great differences in crude oil characteristics. Through HCA and oil-source correlation analysis, the crude oil in the Wenchang B depression was found to be mainly from the W2 source rock. However, in the northern part of the depression, some crude oil was suggested to originate from both W1 and E1 source rock, presenting mixed characteristics. The crude oil in the western Qionghai uplift was mainly derived from W1 and E1 source rocks, with a small part was from the W2 source rock.

Geochemical characteristics and origin of crude oil from Carboniferous volcanic rocks in the Hongche Fault Zone of the Junggar Basin of China

In recent years, significant advances have been made in the exploration of Carboniferous volcanic reservoirs in the Hongche Fault Zone of the Junggar Basin of China, showing good prospects for further exploration. However, the large variation in the physical properties of crude oil and the complex distribution rule inhibit the one-step exploration. In this study, the PM scale of the biodegradation of crude oil and source of crude oil were studied using experimental methods that target the properties, bulk properties and biomarker compounds of crude oil. The exploration potential of crude oil in this area was analysed, and an accumulation model of crude oil was established. Based on the differences in biomarker compounds and the degree of biodegradation, crude oils were divided into four groups and seven subgroups. Additionally, the analysis of the biomarker compounds of crude oil combined with the hydrocarbon-generation history of source rocks showed that there were at least two periods of oil charging in this area. The first period was the late Triassic, with crude oil derived from the P1f source rock. Owing to the strong tectonic activity during the late Indosinian movement, the oil reservoirs were distributed in the footwall of the fault zone, and the oil in the reservoir exhibited different degrees of biodegradation, forming crude oils of subgroup I1, II and III1. The second period was Cretaceous, during which the P1f source rock was in the natural gas generation stage, and the P2w source rock was at a mature stage. A small part of the crude oil formed by the P2w source rock migrated to the Carboniferous reservoirs and mixed with the crude oil formed by the earlier P1f source rock, resulting in crude oils of subgroups I2, III2, and IV2. The crude oil in the studied area originated from the source rocks in the sag during the peak of oil generation. As tectonic activity approached stability in the latter period, it is speculated that there may be well-preserved primary oil and gas reservoirs in the footwall and slope areas of the fault, making these potential exploration sites.

Stratigraphic Characteristics and Sediment-Filling Process of the Early Permian Fengcheng Formation in the Northwestern Margin of the Junggar Basin, Northwest China

The Permian Fengcheng Formation in the Mahu sag of the Junggar Basin is a crude oil reservoir and source rock. However, its stratigraphic characteristics, the boundary marks of the three members (lower, middle, and upper), and the sediment-filling processes are unclear. This study presents the sedimentary systems and sediment-filling processes in an intracontinental rift basin of this area using sedimentary-faces analysis, sequence stratigraphy, well logs, and two-dimensional seismic interpretations. The results show that the Fengcheng Formation consists of three third-order sequence stratigraphy (SQf1, SQf2, and SQf3). The lowest member of the Fengcheng Formation is composed of gray to dark gray thin middle layers of tuff, lacustrine dolomitic mudstone, and argillaceous dolomite near the depocenter. Tuff, siltstone, a small amount of fan–delta glutenite, volcanic breccia, and basalt are present near the fault zone. The logging curve is characterized by a high gamma-ray (GR) value, high amplitude, wavelength growth, and medium frequency. Near the depocenter, the middle member of the Fengcheng Formation comprises gray and gray–black thin layers of lacustrine muddy dolomite and dolomitic mudstone and thin sandstone and mudstone interbedded between tuff and gravel near the orogenic belt. The logging curve displays high-to-low GR values, high amplitude, short wavelength, and high frequency. The upper member of the Fengcheng Formation is not characterized by lesser tuffaceous and dolomitic components but by an increased fan–delta sandy content. Next, the bottom of the upper member is composed of lacustrine mudstone and siltstone interbedded between dolomitic mudstones; whereas, the top of the upper member is dominated by fan–delta coarse sandstone and sandy conglomerate. The logging curve shows low GR values, small amplitude, and continuous stability. The sediment-filling process of the Fengcheng Formation is controlled by fault activity. Overall, the lower and middle members of the Fengcheng Formation expand during the sediment-filling process of the lake basin of the Mahu sag; whereas, the upper member contracts. The strong uplift of the Horst near the Baiquan and Mahu orogenic belts led to an increase in provenance supply, resulting in a contraction of the southwestern margin of the lake basin during the sedimentation period from lower member to upper member of Fengcheng Formation.

ANALISIS PENGARUH SUHU TERHADAP SENSITIVITAS SENSOR PADA HIDUNG ELEKTRONIK UNTUK KEMATANGAN BUAH KELAPA SAWIT

Electronic noses have been developed for decades in many fields. Recently, electronic nose has been used in agriculture to detect the ripeness of fruits because fruits also produce volatile gas during ripening. Oil palm fresh fruit bunches (FFB) is the main source of crude palm oil, its quality depends on the ripeness levels of oil palm FFB. Therefore, electronic detections of oil palm FFB ripeness need to be developed. This study was aimed to investigate the effect of temperature variation on the sensitivity of gas sensors in an electronic nose designed for detecting the ripeness of oil palm FFB. The electronic nose used in this study consisted of 4 sensors which were TGS 2611, TGS 2620, TGS 813 and TGS 822. Samples were peeled fruitlets of ripe oil palm FFB which were heated to temperatures of 30°C, 45°C, and 60°C. Response of each sensor was represented as a trapezoid area of voltage versus time for convenience. The results showed that there was a significant difference in the output voltage of each sensor when the sample temperatures were varied. Fruitlets of oil palm FFB heated at 60°C resulted in higher trapezoid area which mean more volatile gas released. Based on the resulted trapezoid area for each sensor. Sensors of TGS 2611 and TGS 822 are the most sensitive which have higher trapezoid area for the variation of the temperatures.

Classification and source of crude oil in the Linhe Depression, Hetao Basin

Classification and source of crude oil in the Linhe Depression, Hetao Basin

Genesis of H2S in Jurassic associated gas in Pengyang area, Ordos Basin, NW China

The Jurassic Yan'an Formation (J1y) crude oil-associated gas in the Pengyang area of the Ordos Basin contains a certain amount of H2S. The study of its genesis is important for us to predict the distribution of H2S in Mesozoic in the basin. The Chang7 source rock of the Yanchang Formation (T3y) is the principal source of crude oil in the Jurassic Yan'an Formation area. However, H2S is not detected in the crude oil-associated gas of Chang10 to Chang3 members of the Yanchang Formation. As a result, the formation of H2S in the crude oil-associated gas of Yan'an Formation may be related to reservoir and accumulation factors. The study shows that Jurassic formation water has a high salinity and is rich in divalent sulfur, which inhibits the development of sulfate-reducing bacteria (SRB). It is less likely to biologically reduce sulfate to produce H2S. The δ34S values of H2S in crude oil-associated gas of Yan'an Formation are greater than 25‰, which are obviously different from those of volcanic hydrothermal fluid, organic matter, and microbial reduction products, but similar to divalent sulfur isotope values in formation water and about 10‰ negative to sulfate ion in formation water. TSR has generated sulfur isotope distribution and fractionation characteristics in H2S. The temperature measurement of reservoir inclusions in the Jurassic Yan'an Formation shows that the initial filling temperature of oil and gas is higher than 100 °C, and the maximum accumulation forming temperature is 150 °C. The formation water of Yan'an Formation contains a large number of sulfate ions from anhydrite or buried stage. Those rich sulfate ions meet the conditions for a sulfate thermochemical reduction reaction. At the same time, the rich magnesium ions in formation water catalyzed the reaction. Therefore, H2S in Jurassic crude oil-associated gas in the Pengyang area of the Ordos Basin has thermochemical sulfate reduction (TSR) genesis.

Geochemical Investigation of the Cretaceous Crude Oil Reservoirs and Source Rock Samples in One of the Abadan Plain Oilfields, SW Iran

AbstractCrude oil and source rock samples from one of the main oilfields of the Abadan Plain, Zagros, Iran were analyzed geochemically. Rock‐Eval pyrolysis was conducted on Kazhdumi (Upper Cretaceous) and Gadvan (Lower Cretaceous) formations, which are the probable source rocks for the oil in the region. The results indicated that the Kazhdumi Formation can be classified as a fair‐to‐excellent source rock, while the Gadvan Formation can be identified as having poor‐to‐good source rock in the basin. Based on the cross‐plots of HI versus OI and S2 versus TOC, types II and III kerogen were identified from studied source samples in the area. Determination of the main fraction percentages of the Sarvak and Fahliyan crude oils represented that the oils from the Sarvak reservoir are paraffinic‐naphthenic and aromatic‐intermediate, whilst that from the Fahliyan reservoir is paraffinic and paraffinic‐naphthenic. Biomarker ratios of the saturated fractions of oil from both reservoirs indicate that the source rocks formed in reducing marine environments with carbonate‐shale lithology. Furthermore, biomarker data helped to distinguish the degree of biodegradation in the studied oils. According to geochemical analysis, oil samples from the Fahliyan reservoir were generated at a higher thermal maturity than the Sarvak reservoir samples.