Papers by Dr.jacques Connan
Petroleum Geochemistry and Source Rock Potential of Carbonate Rocks, 1984
Journal of Historical Archaeology & Anthropological Sciences, 2018
13 archaeological samples, dated from the Middle Uruk period (c.3500 BC) to the Late Bronze age (... more 13 archaeological samples, dated from the Middle Uruk period (c.3500 BC) to the Late Bronze age (c.1280 BC), were analyzed by geochemical techniques in order to identify bitumen and to attempt to find its origin. Extracts do show that the samples are characteristic archaeological bitumens. Bitumens of Tell Brak were compared to some other archaeological asphalts, to crude oils and natural asphalts. Utilization of carbon isotopes on asphaltenes and biomarkers namely steranes and terpanes allowed us to identify two main areas of bitumen supply, Hit on one side along the Euphrate river, northern Iraq on the other side.
MOM Éditions, 2011
Connan Jacques. Annexe sur CD-ROM. In: Le tell d'Akkaz au Koweït / Tell Akkaz in Kuwait Lyon ... more Connan Jacques. Annexe sur CD-ROM. In: Le tell d'Akkaz au Koweït / Tell Akkaz in Kuwait Lyon : Maison de l'Orient et de la Méditerranée Jean Pouilloux, 2011. pp. 1-32. (Travaux de la Maison de l'Orient et de la Méditerranée, 57
Petroleum is a fragile fluid, a part of which is likely to be destroyed or lost to the atmosphere... more Petroleum is a fragile fluid, a part of which is likely to be destroyed or lost to the atmosphere. The moment crude oil separates from bitumen in the source rock, it begins to undergo compositional changes that continue throughout migration and accumulation. The processes and factors influencing oil composition in an accumulation take effect before, during, and after entrapment. The primary factors influencing oil composition before entrapment are source rock characteristics, primary migration, and secondary migration. The main factors influencing oil composition during entrapment are pressure and temperature, as they establish the conditions under which secondary alteration processes take place. After entrapment, secondary alteration processes influencing oil composition are the effect of thermal maturation, physical and biological degradation, gravity segregation, dysmigration (separation-migration), and deasphalting. These alteration processes can increase the API gravity and gas-oil ratio of the oil, but generally decrease the API gravity. Knowledge of the conditions and mechanisms of degradation are needed to understand the nature and distribution of oil shows and to carry out oil-oil and oil-source rock correlations. Considerable progress has been made in understanding secondary alteration processes, but more is expected as the more poorly understood macromolecular and polar fractions are investigated. Presently, molecular chemistry is a useful tool that can recognize incipient biodegradation, detect oil gravity segregation, and discriminate a pyrobitumen from a precipitated asphaltene, whereas bulk analyses are currently inaccurate.
Kluwer Academic Publishers eBooks, Feb 13, 2006
Journal of Archaeological Science, Sep 1, 2017
Twenty three samples of Egyptian organic materials, spanning from the Old Kingdom to the Copto-By... more Twenty three samples of Egyptian organic materials, spanning from the Old Kingdom to the Copto-Byzantine Period, were investigated by gas chromatography-mass spectrometry. The sample set was comprised of ten balm samples from human mummies, three balms from shrews, and ten samples of residues scraped from jars and amphora from storehouses. This research program was undertaken with two main goals: Firstly to provide complementary data on the mummification balms from both humans and animals with an emphasis on the occurrence of bitumen in mummification mixtures. Secondly to explore whether the jar residues were mixtures that were used for mummification purposes or whether they were pure ingredients stored for various uses including ritual practices. The analysis highlighted that the most abundant constituents of the mummification balms were: fats or oils, waxes, conifer resin, pitch, mastic resin, castor oil, and bitumen. Balms from animal mummies were not found to be significantly different from the balms from human mummies. Residues from potsherds appeared to belong to two categories: pure products (fats and castor oil) and mixtures containing fats, Pinaceae resin and pitch, mastic resin, and castor oil, i.e. the constituents also identified in mummification balms. The mixtures were thus residues of preparations for ritual practices and embalming. This study demonstrates that bitumen is underestimated by the chemical approach currently applied in most archaeometric studies of Egyptian organic residues, which are better suited for the identification of lipids and resinous materials. We thus applied a specific analytical design, targeted at bitumen. Bitumen from the Dead Sea was conclusively identified using as reference materials for comparison, i.e. the present day bitumen from the Dead Sea floating blocks, as well as several bitumens from mummification balms and bitumen lumps unearthed from the archaeological site of Tell Yarmouth near Jerusalem in Israel.
Organic Geochemistry, 1990
Forty low maturity, type I-II kerogens from source rocks and oil shales, ranging in age from Infr... more Forty low maturity, type I-II kerogens from source rocks and oil shales, ranging in age from Infra-Cambrian to Miocene, were examined by transmission electron microscopy (TEM). When previously observed by light microscopy and/or UV fluorescence microscopy the above samples, like a very large number of kerogens, seemed homogeneous and amorphous. In fact, TEM revealed the presence of "ultralaminar" structures in 22 of these "amorphous" kerogens. The abundance of "'ultralaminae" depends on the considered sample and some of the tested kerogens are nearly exclusively composed of "ultralamina" accumulations. Based on thickness, three main groups of "ultralaminae" can be identified. Parallel studies on extant algae indicated that some of the above "ultralaminae" likely derived from the resistant outer walls of microalgae. The fossilization of such outer walls should occur via the "selective preservation" pathway and result in the formation of highly aliphatic "ultralaminar" kerogens. The lack of "ultralaminae" in Infra-Cambrian kerogens is consistent with a cyanobacterial origin.
Organic Geochemistry, Dec 1, 1992
Transmission Electron Microscopy (TEM) observations recently revealed the common occurrence of ve... more Transmission Electron Microscopy (TEM) observations recently revealed the common occurrence of very thin lamellar structures, termed ultralaminae, in kerogens from source rocks and oil shales so far considered as amorphous. Ultralaminae in lacustrine kerogens were shown to derive from the selective preservation of the algaenans occurring in the very thin outer walls of various freshwater Chlorophyceae. The chemical correlation between such algaenans and fossil lacustrine ultralaminae was chiefly based on the production on pyrolysis ofn-alkylnitriles with a typical distribution (bimodal, maxima at C28 and C~6). The origin of marine ultralaminae is investigated in this work. To this end, spectroscopic and pyrolytic studies were carried out on (i) the algaenan forming the very thin outer walls of Nanochlorum eucaryotum (an extant marine Chlorophycea) and (ii) two ultralaminae-containing marine kerogens from the Lower Toarcian shales of Paris basin (Fecocourt and Bray). A high contribution of polymethylenic chains probably linked via ether bridges was observed in these bio-and geopolymers. Furthermore, on pyrolysis they afforded the same n-alkylnitriles with the same distribution (unimodal, maximum at Ct3, lack of Cl7 + compounds). Fossil ultralaminae in marine kerogens therefore derive from the selective preservation of the algaenan-composed very thin outer walls of marine Chlorophyceae such as N. eucaryotum. Algaenans from marine and freshwater Chlorophyeeae and, therefore, marine and lacustrine ultralaminae, should be characterized by sharply distinct n-alkylnitrile distributions.
Journal of Biblical Literature, 1993
AAPG Bulletin, 1993
Biodegradation of hydrocarbons in reservoirs is a widespread phenomenon that is currently observe... more Biodegradation of hydrocarbons in reservoirs is a widespread phenomenon that is currently observed by petroleum organic geochemists in most sedimentary basins. This basic phenomenon is responsible for the occurrence of large, heavy oil deposits referred to as tar mats or tar belts. Biodegradation of crude oils takes place in reservoirs in which oil-eating bacteria may thrive. For this reason, effective and present biodegradation effects are not observed at subsurface temperatures higher than 70-80[degrees]C. Significant compositional changes, especially at a molecular level, still remain linked to the aerobic biodegradation of crude oils. Under favorable circumstances, both alkanes and aromatics are degraded, but when nutrients (N, P, O[sup 2]) are impoverished, aromatics seem to be preferentially removed. Biodegradation extends also to sulfur-bearing aromatics with a preferential removal of alkylated structures. Changes in molecular patterns are used to assess degrees of biodegradation in crude oils. The most bacterially resistant structures are polycyclic alkanes and aromatics. The in-reservoir biodegradation of hydrocarbons does not generate new hydrocarbons, e.g., 25-norhopanes as proposed by several authors. In fact, the selective removal of less resistant structures concentrates preexisting minor families that were not detected on the unaltered crude due to their low absolute concentration. Consequently, the molecular spectrum found in severely biodegraded oils may be considered as highly diagnostic of a part of the primary genetic spectrum of each oil. In outcrop samples, biodegradation is associated with other complementary phenomena such as photooxidation, oxidation, inspissation, evaporation, water washing, etc. Of particular importance are weathering effects linked to oxidation, which entail drastic compositional changes, with neogenesis of resins, asphaltenes, and even insoluble residue.
Journal of historical archaeology & anthropological sciences, Nov 26, 2018
13 archaeological samples, dated from the Middle Uruk period (c.3500 BC) to the Late Bronze age (... more 13 archaeological samples, dated from the Middle Uruk period (c.3500 BC) to the Late Bronze age (c.1280 BC), were analyzed by geochemical techniques in order to identify bitumen and to attempt to find its origin. Extracts do show that the samples are characteristic archaeological bitumens. Bitumens of Tell Brak were compared to some other archaeological asphalts, to crude oils and natural asphalts. Utilization of carbon isotopes on asphaltenes and biomarkers namely steranes and terpanes allowed us to identify two main areas of bitumen supply, Hit on one side along the Euphrate river, northern Iraq on the other side.
Organic Geochemistry, 1984
High performance liquid chromatography (HPLC) on normal phase has been performed on sedimentary r... more High performance liquid chromatography (HPLC) on normal phase has been performed on sedimentary rocks and crude petroleums to obtain fingerprints on polycyclic aromatic hydrocarbons (PAH) separated by degree of aromaticity. Chromatographic fractions containing methylphenanthrenes (MP) and methylchrysenes (MC) have been collected to obtain the relative distribution of these isomers by capillary gas chromatography (GC) and/or high resolution spectrofluorimetry (HRS). Trends in the distribution are tentatively correlated with the maturity of the studied samples.
AAPG Bulletin, Mar 1, 1970
Organic Geochemistry, May 1, 2009
... Armelle Charrié-Duhaut a , Corresponding Author Contact Information , E-mail The Correspondin... more ... Armelle Charrié-Duhaut a , Corresponding Author Contact Information , E-mail The Corresponding Author , Jacques Connan a , Mike Darnell b , Jorge Spangenberg c , Ewa Szymczyk b , Adry Bissada b and Pierre Albrecht a. ...
Annales d'Université "Valahia" Târgovişte. Section d'Archéologie et d'Histoire, 2011
Molecular studies of archaeological remains using a fractionation scheme of organic extracts and ... more Molecular studies of archaeological remains using a fractionation scheme of organic extracts and mass spectrometric techniques (GC-MS) allow identification of specific biomarkers. Such components are likely to provide information about the type of organic substances present and, more extensively on their history. In this paper, special emphasis has been put on the necessity for precise structural identification to distinguish beeswax and cuticular waxes. The results of the analysis of two unknown residues are also reported: the content of a pilgrim flask (Egypt, XXVI th dynasty, 664-525 BC) and the wall coating of Middle Age undergrounds (Corrèze, France).
Crude oils and rock samples from carbonate basins in France (Aquitaine), Guatemala, Iraq, and Tun... more Crude oils and rock samples from carbonate basins in France (Aquitaine), Guatemala, Iraq, and Tunisia/Libya were analyzed by the usual methods of organic geochemistry. The studies were based mainly on computerized gas chromatography-mass spectrometry, with special emphasis on mass fragmentography. Several classes of biological markers were used for the purpose of characterizing the environments of deposition and for correlating crude oils with source rocks. The following specific features commonly were observed in the oil and rock samples from these carbonate formations: (1) the predominance of normal alkanes with even carbon numbers, usually more pronounced in the rocks than in the oils; (2) a ratio of pristane to phytane mostly below 1; (3) the presence in significant concentrations of the higher homologs of the hopane triterpanes, up to C 35 (more important in rocks than in oils); (4) usually small amounts of steranes (C^-C^ and C 27-C 29 ranges), with predominance of non-rearranged structures; and (5) commonly an unusually high concentration of individual isoalkanes (Qj) and cyclohexylalkanes (C 21). These molecular criteria partly reflect an important microbial contribution, which is usually more pronounced in highly anoxic environments. Furthermore, they have been used successfully in correlations among crude oils and between crude oils and their source rocks. The results agree with other geochemical and geological data.
Un ensemble exceptionnel d’outils provenant d’un atelier de travail du silex a ete decouvert sur ... more Un ensemble exceptionnel d’outils provenant d’un atelier de travail du silex a ete decouvert sur le site de Ras Shamra (Syrie). Les silex mis a jour ont ete plus particulierement utilises pour la fabrication ou la reparation de faucilles. Une etude a ete realisee afin de determiner la nature et l’origine du materiau organique retrouve a la surface de certains silex et vraisemblablement employe comme adhesif pour fixer les silex sur des manches de faucilles. L’analyse par chromatographie en phase gazeuse couplee a la spectrometrie de masse des hydrocarbures satures de ces echantillons montre qu’ils sont principalement constitues de bitume severement altere. L’analogie de la composition isotopique du carbone ainsi que des profils moleculaires de ces bitumes avec ceux d’asphaltes naturels provenant du gisement de Kfarie, situe a proximite du site de Ras Shamra, a permis d’etablir que ce gisement etait a l’origine des echantillons de bitumes etudies. Ces profils moleculaires sont caract...
Une pirogue monoxyle gallo-romaine a ete decouverte en 2007 dans la Saone, lors d’une prospection... more Une pirogue monoxyle gallo-romaine a ete decouverte en 2007 dans la Saone, lors d’une prospection subaquatique a Sassenay. Il s’agit d’un des rares temoins de cette famille architecturale pour la periode dans le bassin rhodanien. Mesurant 8,40 m de longueur, l’embarcation en chene apparait particulierement cintree.
Petroleum is a fragile fluid, a part of which is likely to be destroyed or lost to the atmosphere... more Petroleum is a fragile fluid, a part of which is likely to be destroyed or lost to the atmosphere. The moment crude oil separates from bitumen in the source rock, it begins to undergo compositional changes that continue throughout migration and accumulation. The processes and factors influencing oil composition in an accumulation take effect before, during, and after entrapment. The primary factors influencing oil composition before entrapment are source rock characteristics, primary migration, and secondary migration. The main factors influencing oil composition during entrapment are pressure and temperature, as they establish the conditions under which secondary alteration processes take place. After entrapment, secondary alteration processes influencing oil composition are the effect of thermal maturation, physical and biological degradation, gravity segregation, dysmigration (separation-migration), and deasphalting. These alteration processes can increase the API gravity and gas-oil ratio of the oil, but generally decrease the API gravity. Knowledge of the conditions and mechanisms of degradation are needed to understand the nature and distribution of oil shows and to carry out oil-oil and oil-source rock correlations. Considerable progress has been made in understanding secondary alteration processes, but more is expected as the more poorly understood macromolecular and polar fractions are investigated. Presently, molecular chemistry is a useful tool that can recognize incipient biodegradation, detect oil gravity segregation, and discriminate a pyrobitumen from a precipitated asphaltene, whereas bulk analyses are currently inaccurate.
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Papers by Dr.jacques Connan