Origin Of Petroleum Research Articles

Polycyclic aromatic hydrocarbons in coastal sediments of southwest Taiwan: An appraisal of diagnostic ratios in source recognition

Fifty-seven surface sediment samples were collected from the coast of southwest Taiwan and analyzed for polycyclic aromatic hydrocarbons (PAHs). Concentrations of total PAHs (28 PAH compounds) ranged from 15 to 907 ng g −1 dry weight. Diagnostic ratios showed that PAHs in the sediments of the Gaoping estuary were predominantly of petroleum origin, whereas sediments from the Kaohsiung coast contained principally combustion-derived PAHs. Principal component analysis indicated that emissions from automobiles and coal burning were the main sources of combustion-derived PAHs. The relatively high ratios of perylene/penta-aromatic PAH isomers in sediments from the Tainan coast and some off-shore stations on the Kaohsiung coast suggest a significant diagenetic PAH contribution. The study shows that certain diagnostic ratios are useful and sensitive in delineating the distribution of PAHs from specific sources in southwest Taiwan. The phenanthrene/anthracene ratio is a better indicator than the methylphenanthrenes/phenanthrene ratio for tracing petrogenic PAHs, and the benzo( a)anthracene/chrysene and indeno(1,2,3- c, d)pyrene/benzo( g, h, i)perylene ratios are more specific than the benzo( a)pyrene/benzo( e)pyrene and benzo( b)fluoranthcene/benzo( k)fluoranthcene ratios in distinguishing PAHs from various pyrogenic sources.

Polycyclic aromatic hydrocarbons and effects on marine organisms in the Istanbul Strait

Surficial sediments and mussels ( Mytilus galloprovincialis) from the Istanbul Strait and Marmara Sea were analysed for sixteen parent polycyclic aromatic hydrocarbon (PAH) contents by gas chromatography-mass spectrometry (GC-MS) employing isotope dilution technique. Microalgae toxicity testing was applied to sediment elutriates and biological responses in terms of filtration rate and lysosomal stability were measured in mussels. Total PAH concentrations ranged from 2.1 to 3152 ng g − 1 dry wt in sediments and from 43–601 ng g − 1 wet weight in mussels. Molecular indices of phenanthrene/ anthracene, fluoranthene/pyrene and benzo(a)anthracene/chrysene were used to differentiate between pyrolytic and petroleum origin. Results showed that most of the contamination originates from high temperature pyrolytic inputs with some slight contribution of petrogenic PAH. PAH in sediments were frequently lower than the National Oceanic and Atmospheric Administration (NOAA)–ERM (Effects Range Medium) index. Results of sediment elutriate toxicity testing and biomarkers indicate that the cause of negative effects in sediments may result from different classes of pollutants and does not only relate with PAH contamination. Mussels from most of the stations showed both reduced lysosomal membrane stability and filtration rate indicating disturbed health although the two biomarker results did not always complement each other. The effect studies showed that the pollutants in the strait ecosystem have more pronounced effects in the middle parts than those at the Black Sea entrance.

Obtenção da massa molar de asfaltenos através de osmometria de pressão de vapor

A massa molar é uma propriedade essencial na caracterização de asfaltenos e um dos principais parâmetros de entrada nos modelos para a predição da precipitação. Na literatura são relatadas massas molares entre 1000 e 10000 g.mol-1 para os asfaltenos, variando em função da técnica, natureza do petróleo, tipo de solvente e temperatura. Neste trabalho foi determinada a massa molar média numérica para dois asfaltenos em tolueno, o C7I (insolúveis em heptano) e o C5I (insolúveis em pentano) através da osmometria de pressão de vapor. Os dados experimentais foram avaliados levando em consideração efeitos da agregação dos asfaltenos em solução e sua maior dispersão em baixas concentrações. Foram feitos ainda ajustes matemáticos respeitando a tendência das curvas para diluições infinitas buscando produzir melhores resultados no valor da massa molar. Os valores obtidos foram comparados com os métodos convencionais aplicados à análise da osmometria de pressão de vapor, e situaram-se entre 3200 e 5200 g.mol-1 para o asfaltenos C5I e entre 4100 e 5400 g.mol-1 para o C7I.

Origin of petroleum in the Neoproterozoic–Cambrian South Oman Salt Basin

The South Oman Salt Basin (SOSB) is host to the world’s oldest known commercial deposits. Most of the South Oman oils have been proven to be associated with the source rocks of the Neoproterozoic to Cambrian Huqf Supergroup, but the assignment of oils to specific Huqf intervals or facies has been hampered by the geochemical similarity of the organic matter across the entire Huqf sequence, possibly as a consequence of limited change in the local palaeoenvironment and biota over the time of its deposition. This study was conducted to establish improved correlations between organic-rich rock units and reservoir fluids in the SOSB through detailed molecular and isotopic analysis of the Huqf Supergroup, with special emphasis directed towards understanding the Ara carbonate stringer play.Unusual biomarkers, tentatively identified as A-norsteranes, show distinctive patterns among carbonate stringer oils and rocks different from those observed in Nafun sediments and Ara rocks from the Athel basin. These putative A-norsteranes form the basis for new oil-source correlations in the SOSB and provide for the first time geochemical evidence of a self-charging mechanism for the carbonate stringer play. The paucity of markers specific to the Nafun Group (Shuram, Buah and Masirah Bay formations) confounds attempts to quantify their respective contributions to Huqf oil accumulations. Nafun inputs can only be determined on the basis of subtle differences between Nafun and Ara biomarker ratios. The most useful geochemical characteristics delineating Nafun Group organic matter from Ara Group intra-salt source rocks included: low relative abundance of mid-chain monomethyl alkanes (X-compounds); low relative abundance of gammacerane, 28,30-dinorhopane, 25,28,30-trinorhopane and 2-methylhopanes; low C22T/C21T and high C23T/C24T cheilanthanes ratio values. Based on these parameters, molecular evidence for major contributions of liquid hydrocarbons from Nafun Group sediments (Shuram, Buah and Masirah Bay formations) is lacking. Our results suggest that the majority of SOSB hydrocarbon accumulations originate from within the Ara group, either from the carbonate stringers or from the package of sediments that comprises the Thuleilat, Athel Silicilyte and U shale formations. Subtle aspects of the composition of some carbonate stringer and post-salt Huqf oils could suggest some degree of sourcing from the Nafun rocks but stronger evidence is needed to confirm this.

Purification of water from oil microdrops

The problem of purifying water from microscopic oil drops without using reagent heating has been solved using the technique of a directed motion of drops, i.e., the method of heterogeneous hydrodynamic coagulation. The efficiency of water purification from microscopic oil drops, including those of the petroleum origin, is equal to 95–99% per one stage. The purification process lasts 10–30 min.

Petroleum Hydrocarbon Contamination in Surface Sediments of Beiluohe Basins, China

Twenty-two surface sediment samples were collected from Beiluohe River, China, in 2005. Saturated hydrocarbons analysis was carried out on different river sediments in order to detect possible contaminations by petroleum development. Total concentrations of hydrocarbons in the sediments ranged from 6.4-147.3 microg g(-1) (dry wt) with an average of 76.8 microg g(-1), revealing relatively low to medium contamination in studied areas in spite of oil development for many years. The THC levels in the mainstream of Beiluohe River were relatively low. Sediment samples with higher total hydrocarbon concentrations were from the sites related to the petroleum activities or urban discharges. Gas chromatographic distribution patterns of n-alkanes are characteristic of petroleum in most samples. They show a strong unresolved complex mixture (UCM) with a small predominance of odd on even numbered n-alkanes. On the other hand, pentacyclic triterpanes and steranes occurred in all analyzed sediments and displayed similar signatures that are characteristic of mature organic matter contribution from oil contaminations. Hydrocarbons of terrestrial origin were also detected in the samples. However, contribution from plantwax hydrocarbons is overshadowed in samples by hydrocarbons of petroleum origin. This is obvious by the presence of the high relative abundance of UCM, and the identification of mature hopane and sterane in samples.

A review and technical summary of the AAPG Hedberg Research Conference on “Origin of petroleum—Biogenic and/or abiogenic and its significance in hydrocarbon exploration and production”

A research conference originally scheduled as a Hedberg Research Conference examining the origins of oil and gas was held in Calgary, June 2005. This report summarizes the 14 presentations made at the conference, which discussed data and evidence regarding the abiogenic and biogenic origins of petroleum. In addition, the postpresentation discussion is summarized. Multiple concepts for the abiogenic formation of petroleum were presented. These concepts fell mostly into two broad families: mantle degassing associated with the polymerization of low molecular weight compounds and serpentization in association with Fischer-Tropsch reactions. The Fischer-Tropsch reactions are catalyzed reactions in which carbon monoxide and hydrogen are converted into hydrocarbons. The presentations on the biogenic origin presented a uniform model in which sedimentary organic matter is thermally converted to oil and gas. Little common ground was found to exist between the abiogenic and biogenic schools of petroleum formation, with the possible exception of the importance of fluid flow in controlling the formation of hydrocarbon accumulations. Although few, if any, conference participants changed their perspectives, most concluded that the meeting was informative and a useful exercise.

Fluid Evolution During Burial Diagenesis and Subsequent Orogenetic Uplift: The La Vid Group (Cantabrian Zone, Northern Spain)

Abstract The investigated section of the Lower Devonian La Vid Group (Cantabrian Zone, northern Spain) was deposited in a rifted-continental-margin setting, which in the Carboniferous evolved into a foreland basin, affected by Variscan thin-skinned folding and thrusting. Soon thereafter the originally linear orogenic belt underwent secondary curvature, forming the Variscan Ibero–Armorican Arc. This bending caused extension, crustal thinning, and strike-slip movements in the outer part of the orocline, to which the area of our investigation belongs. Subsequently the Variscan orogen subsided in Mesozoic and Cenozoic times, was covered by sediments of unknown thickness, and was affected by Alpidic tectonics. The Paleozoic Cantabrian Basin is an outcrop analogue for kilometer-scale differences in type and degree of porosity and cementation that can be expected in foreland basins of other areas as well. Origin of cements and related fluids in the La Vid carbonates can be described by three distinct fluid-evolution mechanisms: local in-situ fluid generation, mixing of external with internally generated fluids, and incursion of exotic fluids. The oldest recorded fluid belongs to the basin stage in pre-Variscan times. Upward migration of an in-situ generated fluid from underlying organic-rich shales through iron-rich sandstones into the carbonates of the La Vid Group was accompanied by the precipitation of various Fe-carbonates in various stratigraphic positions of this succession. Among the cements are ferroan saddle dolomites with inclusions of solid bitumen in the lower part and mature petroleum in the upper part of the succession. Assuming a common origin of petroleum and aqueous fluid inclusions in the ferroan saddle dolomite, trapping conditions of 114 to 130°C and a pressure of about 38.5 to 40.5 MPa were determined; this corresponds to a burial depth of about 3850 to 4050 m. The second important fluid event exhibits mixing of a low-salinity internally generated local fluid with an exotic high-salinity fluid of widespread occurrence. This fluid is attributed to the time of Variscan orogenesis, probably the formation of the Cantabrian orocline, based on several tectonic features occurring in the cements. Clear saddle dolomite precipitated during this fluid event in the dolostone unit of the La Vid Group only. These dolomites exhibit a distribution of zoned fluid inclusions from low salinity in the cores to high salinity in the outer parts of the crystals. Minimum trapping temperatures are 160 to 170°C at the core and temperatures of 110 to 120°C at the rim. Higher temperatures in the rim (up to 210°C) appear to have resulted from post-entrapment reequilibration (stretching) of the inclusions during Variscan deformation. The last cementation phase was caused by a cool and oxidizing fluid, related to tectonic activity, most probably of Alpidic age. This fluid precipitated calcite, celestite, and kaolinite and recrystallized former Fe-carbonate cements to calcite and to Fe-oxyhydroxides. Fluid inclusions in celestite have low salinities, ruling out basinal brines and pointing to a meteoric or marine origin. Occurrences of these cements in various locations all over the Cantabrian Zone imply a large-scale fluid event.

Debate over the origin of petroleum: A reply to WAN Lan-sheng's paper

Abstract This paper discusses the Mr. Wang Lansheng's arguments about the origin of petroleum. It is well known that metal elements and their isotopes can be combined with organic compounds to form coordinating ions or complex compounds, which can be applied to petroleum tracing and isotopic dating. The Fischer-Tropsch reaction can synthesize different kinds of hydrocarbons (including crude oils), under different catalysts, higher temperatures and pressures. Daqing's exploration shows that abiogenic gas not only is existent, but also can form big gas reservoirs, such as the Xincheng Gas Pool. In the Tarim Basin, the Silurian bitumen whose reserves are 917.8×10 8 t was generated by inorganic reaction rather than by organic matter. Abiogenic oil and gas were also found in meteorites and in continental scientific drillings. Some other topics related to the origin of petroleum are also discussed. According to the inorganic origin theory of petroleum, some exploration targets are presented in this paper.

Organic pollutants (PAHs, PCBs) in sediments from the Mar Piccolo in Taranto (Ionian Sea, Southern Italy)

Polychlorinated biphenyls (PCBs) and 17 parent polycyclic aromatic hydrocarbons (PAHs) were determined in surface sediments from nine stations in the Mar Piccolo of Taranto (Ionian Sea, Southern Italy). Total PAH concentrations ranged from 380 to 12,750 μg/kg d.w., while total PCB levels ranged from 2 to 1684 μg/kg d.w.; this values were higher than those found in others marine coastal areas of the Mediterranean Sea. For PAHs, low molecular weight/high molecular weight, phenanthrene/anthracene and fluoranthene/pyrene ratio were used for discriminating between pyrolitic and petroleum origin. Results showed that PAHs were mainly of pyrolitic origin. PCB and PAH levels in sediments were compared with Sediments Quality Guidelines (ERM–ERL, TEL–PEL indexes) for evaluation probable toxic effects on marine organism. Finally, ERM and PEL quotients were used to evaluate the degree to which chemicals exceed guidelines. Results suggest an ecotoxicological risk for benthic organisms mainly in the first inlet, where high concentrations of PCBs were found in sediments influenced by harbour activities.

Determination of High-Molecular-Weight n-Alkanes of Petroleum Origin by High-Temperature Gas Chromatography

This paper deals with the identification and determination of high-molecular-weight n-alkanes of petroleum origin using high-temperature gas chromatography (HTGC). Analysed samples, which were the concentrates of saturated hydrocarbons, differed in both the total content of n-alkanes and their distribution. They were analysed on various types of HTGC columns differing in length and inner diameter. While the determined total content of n-alkanes was comparable for all the chromatographic columns, differences were found in the efficiency of separation of n-alkanes over C40 as well as in their quantitative elution.

North Slope, Alaska: Source rock distribution, richness, thermal maturity, and petroleum charge

Four key marine petroleum source rock units were identified, characterized, and mapped in the subsurface to better understand the origin and distribution of petroleum on the North Slope of Alaska. These marine source rocks, from oldest to youngest, include four intervals: (1) Middle–Upper Triassic Shublik Formation, (2) basal condensed section in the Jurassic–Lower Cretaceous Kingak Shale, (3) Cretaceous pebble shale unit, and (4) Cretaceous Hue Shale. Well logs for more than 60 wells and total organic carbon (TOC) and Rock-Eval pyrolysis analyses for 1183 samples in 125 well penetrations of the source rocks were used to map the present-day thickness of each source rock and the quantity (TOC), quality (hydrogen index), and thermal maturity (Tmax) of the organic matter. Based on assumptions related to carbon mass balance and regional distributions of TOC, the present-day source rock quantity and quality maps were used to determine the extent of fractional conversion of the kerogen to petroleum and to map the original TOC (TOCo) and the original hydrogen index (HIo) prior to thermal maturation. The quantity and quality of oil-prone organic matter in Shublik Formation source rock generally exceeded that of the other units prior to thermal maturation (commonly TOCo 4 wt.% and HIo 600 mg hydrocarbon/g TOC), although all are likely sources for at least some petroleum on the North Slope. We used Rock-Eval and hydrous pyrolysis methods to calculate expulsion factors and petroleum charge for each of the four source rocks in the study area. Without attempting to identify the correct methods, we conclude that calculations based on Rock-Eval pyrolysis overestimate expulsion factors and petroleum charge because low pressure and rapid removal of thermally cracked products by the carrier gas retards cross-linking and pyrobitumen formation that is otherwise favored by natural burial maturation. Expulsion factors and petroleum charge based on hydrous pyrolysis may also be high compared to nature for a similar reason.

Genesis of biomarker hydrocarbons in the environment and their role in assessing an oil pollution source

Oil spills are classified according to chemical types that reflect qualitative and quantitative changes in petroleum composition during biodegradation in soil. Possible trends in composition of biomarker petroleum hydrocarbons in polluted soil, as determined by natural and climatic conditions and by activation of soil micro-flora, were revealed. It was shown that the use of selective bioremediation methods could lead to a noticeable redistribution of the relative amount of C27:C28:C29 steranes in marine crude oils owing to more intense degradation of C27 steranes (5α, 14β, 17β, 20R and 20S, as well as 5α, 14α, 17α, 20R and 20S) as compared with their higher C29 homologues. The observed changes in the composition of steranes suggest another, namely, terrigenous origin of petroleum, and, thus, may lead to an erroneous conclusion concerning the genotype of crude oil as a pollution source. It was found that hopane hydrocarbons are highly stable under similar conditions. It was shown that the set of biomarker hydrocarbons might be useful as biological indicators in the assessment of a petroleum pollution source.

Elementary Students' Ideas Concerning Fossil Fuel Energy

Forty-two academically gifted and thirty-two average-achieving elementary students in grades one through six were interviewed to determine ideas concerning fossil fuel energy. There were no significant differences between the responses of the two populations. Major categories of misconceptions encountered during interviews included misconceptions about: configuration or distribution of petroleum reservoirs, gasoline manufacture and storage, the origin of petroleum, the importance of petroleum in our society, petroleum prospecting and recovery; and the nature of coal and natural gas.Misconceptions about fossil fuels arise for a variety of reasons. Students sometimes misunderstand scenes from movies, televisions shows or cartoons, make incorrect analogies with more familiar experiences, misinterpret diagrams in printed materials, misconstrue the meanings of symbols, or confuse similar-sounding terms or words with more than one meaning.Sixty-seven preservice teachers responding to a ten-question survey to investigate the persistence of fossil fuel misconceptions into adulthood revealed many held the same ideas as elementary students, confirming the importance of addressing younger students' ideas during instruction.

Methods of Analysis of High-Wax Crude Oils. Resins, Asphaltenes, Paraffin Waxes

Methods of determining the content of resins, asphaltenes, and paraffin waxes and distillation of the waxes applied to high-wax crudes are reported. The method is based on the experience from many years of research on ozocerites, minerals of petroleum origin that primarily consist of paraffin waxes, and crudes with a high wax content.

Properties of particleboard bond with rice bran and polymeric methylene diphenyl diisocyanate adhesives

Rice straw can be used as a fiber source for the manufacture of particleboards. Polymeric methylene diphenyl diisocyanate (PMDI) is widely used as an adhesive for manufacturing such products. PMDI has the ability to bind rice straw despite the wax present on the surface of the straw. Its relatively high cost, petroleum origin, and toxicity in its uncured state are concerns to the rice particleboard industry. A less expensive and environmentally friendly rice bran adhesive may be used to replace a portion of PMDI and still give quality products. The objective of this study was to evaluate the quality of particleboard bond with rice bran based adhesive. In this experiment, rice bran adhesive (RBA) was used to replace 10, 20, and 30% of PMDI adhesive. The properties of the resulting mixed adhesive products were then evaluated and compared with particleboard bond with only PMDI. Up to 30% of the PMDI could be replaced with RBA to yield products with properties similar to those of PMDI bond particleboard.

Composition and origin of hydrothermal petroleum and associated lipids in the sulfide deposits of the Rainbow field (Mid-Atlantic Ridge at 36°N)

The lipid components in hydrothermal sulfide deposits from the Rainbow vent field (Mid-Atlantic Ridge at 36°N) were studied by gas chromatography/mass spectrometry. The Rainbow vent field is one of two known active hydrothermal systems related to abyssal circulation, where high-temperature fluids are formed during serpentinization of ultrabasic crustal rocks. The major amount of the extractable organic matter from the sulfides consists of normal and branched alkanes, UCM, PAHs, terpenoids, and fatty acids. The branched alkanes are comprised of unique gem-diethylalkane series, possibly from sulfide oxidizing bacteria, and biphytanes from archaea. The characteristic lipid and biomarker compounds found in the hydrothermal samples support a predominantly biological origin of the bitumens from the thermal transformation of the biomass of microorganisms (bacteria and archea) and minor macrofauna of this vent field. A search for molecular evidence for abiogenic thermocatalytic synthesis of organic compounds was negative. However, methane in the hydrothermal fluids and possibly a minor amount of the alkanes in the sulfides may be of an abiogenic origin in the Rainbow vent field.

English

There has been considerable interest in the development and production of biodegradable polymer to solve the current problem of pollution caused by the continuous use of synthetic polymer of petroleum origin. Polyhydroxyalkanoates (PHAs) are known to be accumulated as intracellular inclusion in some bacteria. The materials properties exhibited by PHAs, ranging from stiff, brittle to rubber-like makes it a close substitute for the synthetic plastic. The high cost of PHAs production has restricted its applications. The possibility of producing this polymer commercially and at comparable cost has been the main focus in this area.   Key words:  Polyhydroxyalkanoates, biodegradable polymer, bioplastic, poly(3-hydroxybutyrate), biosynthesis.

Use of rice bran oil and epoxidized rice bran oil in carbon black–filled natural rubber–polychloroprene blends

AbstractIn the present study we report the results obtained on the use of rice bran oil (RBO), a naturally occurring nontoxic oil, and its epoxidized variety (epoxidized RBO, or ERBO) in the compounding and vulcanization of different natural rubber–chloroprene rubber (NR–CR) blends. The processability, cure characteristics, and physical properties of the blends prepared with these oils were compared with those of control mixes prepared with aromatic oil. The optimum cure time and scorch time values of the different blends prepared with these oils were found to be lower than those of the respective control blends prepared with aromatic oil. Evaluation of physical properties of the different experimental blends showed that replacement of aromatic oil with these oils did not adversely affect their physical properties. Because RBO contains a good amount of free fatty acids it was tried as a coactivator in addition to its role as a processing aid. The level of these oils required for the blend preparation was optimized in a Brabender plasticorder. Physical properties such as tensile strength, elongation at break, tear strength, swelling index, and abrasion loss, for example, were evaluated for both experimental and control mixes. Comparison of cure characteristics and physical properties of the blends prepared with aromatic oil and with these oils showed that these oils could be used in place of aromatic oil in the above blends. It is also to be noted that aromatic oil is of petroleum origin and is reported to be carcinogenic. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4084–4092, 2003

Petroleum biomarker sources in suspended particulate matter and sediments from the Fraser River Basin and Strait of Georgia, Canada

In the Fraser River Basin and the Strait of Georgia, a pristine hydrocarbon background is evident in older sediments and suspended sediments from remote regions. This natural background has been augmented over the past century by variable amounts of combustion PAHs and petroleum hydrocarbons derived from human activities, with impacts most evident near industrialised or highly populated regions. Traditional petroleum indicators, including alkane and alkyl PAH distributions and unresolved complex mixtures (UCMs), identify petroleum contamination in suspended particulates transported by the Fraser River and in modern sediments from lakes and rivers in the lower Fraser Basin and the Strait of Georgia. However, these markers have proven to be of limited quantitative use either because they overlap combustion PAH profiles or because they are prone to degradation in the environment. More specific and refractory petroleum markers such as the steranes, rearranged hopanes and tri- and tetracyclic terpanes are found where there are enhanced concentrations of traditional indicators, confirming previous assignments of petroleum contamination near industrial regions. Furthermore, the low or non-detectable quantities of these biomarkers in remote regions reinforce the conclusion that these areas remain pristine and suggest that these markers may provide useful indicators of any future contamination. Biomarkers of petroleum origin (reservoir location or age) do not provide incisive indicators of the origins of hydrocarbon contamination in the Fraser Basin but they have helped to narrow down the sources. In particular, the absence of structurally rearranged hopanes (25,28,30-trisnorhopane and 28,30-bisnorhopane) rules out contamination from Californian oils, while the presence of enhanced oleanane in samples from the lower Fraser River suggests a source in coal dust lost during railroad transportation to the coast.