classification of huminite iccp system 1994 abstract in the new classification iccp system 1994 the maceral group huminite has been revised from the previous classification iccp 1971 int handbook coal petr suppl to 2nd ed to accommodate the nomenclature to changes in the other maceral groups especially the changes in the vitrinite classification iccp 1998 the new vitrinite classification iccp system 1994 fuel 77 349 358 the vitrinite and huminite systems have been correlated so that down to the level of sub maceral groups the two systems can be used in parallel at the level of macerals and for finer classifications the analyst now has according to the nature of the coal and the purpose of the analysis a choice of using either of the two classification systems for huminite and vitrinite this is in accordance with the new iso coal classification that covers low rank coals as well and allows for the simultaneous use of the huminite and vitrinite nomenclature for low rank coals

generation of gas and oil from coal and other terrestrial organic matter abstract late carboniferous permian sedimentary rocks contain the world s largest coal reserves which have generated and released gas but little if any oil in comparison organic matter deposited in lacustrine fluvial deltaic or brackish water sediments has sourced large quantities of waxy oils in countries such as china australia the u s a argentina venezuela and indonesia plus gas and condensate in deltas worldwide why is more oil coming from land derived organic matter disseminated in sediments than from the carboniferous permian coal beds which also are land deposits the answer appears to be in the hydrogen content and the ease of migration when organic matter and coals have high hydrogen contents relative to carbon they can form oil when the hydrogen is low mainly gas is formed most of the world s coal is low in hydrogen whereas much of the terrestrial organic matter disseminated in sediments is higher in hydrogen so it forms more oil also both gas and oil are adsorbed on coal more strongly than on the disseminated kerogen of sedimentary rocks this makes migration of oil out of the coal more difficult compared to migration from conventional shale source rocks

geochemical and petrographic characterization of humic coals considered as possible oil source rocks abstract recently several groups of authors have argued that coals should be considered as possible source rocks for oil as well as being source rocks for gas the present study was undertaken with the objective of evaluating the various methods of characterization of maturation levels and oil potentials of coals from within the oil window it was found that the degree of maturation of a coal could not be specified exactly no matter what parameter describing coal rank was used this lack of precision obviously makes it difficult to compare coals especially from the point of view of their petroleum potential which varies during the course of coalification furthermore quantitative evalution of the oil potential of coals is difficult particularly the present day petrographic concept of exinite does not seem very well adapted to this quantitative evaluation differences in oil potential might in fact be better explained by the relative proportions of the various vitrinite macerals which are present rather than by the proportion of exinite in the coal

relationship between petroleum composition and depositional environment of petroleum source rocks crude oils of nonmarine source can be distinguished from those of marine shale source and from oils originating in marine carbonate sequences by using a battery of geochemical parameters as demonstrated with a sample suite of nearly 40 oils a novel parameter based on the presence of c30 steranes in the oil was found to be a definitive indication of a contribution to the source from marine derived organic matter a second novel parameter based on monoaromatized steroid distributions was effective in helping to distinguish nonmarine from marine crudes and can be used to gauge relative amounts of higher plant input to oils within a given basin sterane distributions were similarly useful for detecting higher plant input but were less effective than monoaromatize steroid distributions for making marine versus nonmarine distinctions concentrations of high molecular weight paraffin can also be effective nonmarine indicators but are influenced by maturation and biodegradation processes certain algal derived nonmarine oils may show little high molecular weight paraffin response oils from carbonate sources with a few exceptions can be distinguished by having low pristane phytane ratios low carbon preference indexes and high sulfur contents gammacerane indexes and carbon isotope ratios of the whole crude are not effective in distinguishing these types of environmental differences on a global basis

the petroleum potential of tertiary coals from western indonesia relationship to mire type and sequence stratigraphic setting abstract more than 500 deltaic sediments from 14 basins in western indonesia were subjected to detailed geochemical petrographic and palynological analysis the resultant data represent each of the main peat forming tectonostratigraphic episodes paleogene syn rift transgressive paleogene neogene post rift transgressive and neogene syn tectonic regressive of the indonesian tertiary the coals are hydrogen rich with average hydrogen index hi of 250 300 and atomic h c ratios of 1 0 1 3 where immature paleogene coals from syn rift transgressive systems tracts are more hydrogen rich than neogene coals from syn tectonic regressive systems tracts and upon pyrolysis yield lower gas oil ratios implying they are more oil prone pliocene coals from a strongly regressive sequence in the sumatran fore arc are very hydrogen poor with average hi of 138 indonesian coals display a systematic increase in hi with increasing rank peaking at a tmax of c 430 c suggesting that rock eval pyrolysis underestimates petroleum potential in low rank coals the increase in hi is accompanied by a decrease in s1 toc ratio and the disappearance of suberinite and resinite reflecting the assimilation of these macerals into the coal matrix with increasing diagenesis petrographic analyses reveal a very poor correlation between liptinite content and hi the term detrovitrinite index di is coined to describe the ratio of detrovitrinite total vitrinite a better relationship between hi and di suggests that vitrinite type is a more important control on petroleum potential than liptinite content the coals are classified into four sub types i iv on the basis of their pyrolysis potential and petrographic composition sub types i ii and iii are low ash coals and are likely to have been deposited in raised mires sub type i is hydrogen rich and primarily represents middle to late miocene coals deposited in a regressive megasequence sub type ii coals are hydrogen poor and occur in multiple tectonostratigraphic settings sub type iii consists of very hydrogen poor pliocene coals from the rapidly subsiding west sumatran fore arc sub type iv is hydrogen rich and consists of high ash eocene coals deposited in submerged mires in a transgressive syn rift setting a close relationship between hi and tissue preservation index tpi suggests that the degree of degradation of the peat is an important factor in determining petroleum potential highly degraded peats result in hydrogen rich coals with a higher proportion of vitrinite of detrital or allochthonous origin the degree of degradation is most likely related to the amount of time the peat spends within the zone of influence of the water table and is unlikely to be directly related to tectonostratigraphic setting

comparison of three series of organic matter of continental origin abstract three series of sediments containing land plant derived organic matter were studied they include wells from mahakam delta indonesia miocene douala basin cameroon upper cretaceous and eastern paris basin france paleozoic all of the kerogens and coals isolated from these series can be related to type iii in a van krevelen diagram however they obviously differ in terms of chemical structure as reflected by their pyrolysis gc patterns and by their bitumen composition these observations indicate the variations in the nature of land plant derived sedimentary organic matter and thus differences in quantity and composition of the hydrocarbons which are are released upon maturation based on hydrocarbons potential of the insoluble organic matter and on pyrolysis gc there is no reason to disregard coals and to favor shales as potential source rocks in these two deltaic sequences moreover we assume that the bitumen depletion in coal samples is a reflection of loss by migration which is favored in coals when compared to shales the gc patterns of the residual saturates compared to the pyrolysis gc patterns of the related insoluble coals suggest that migration of hydrocarbons proceeds in these coals without any significant alteration of their distribution at least in the c15 range

unusual distributions of long chain n alkanes and n alkenes in antarctic soil abstract hydrocarbons in soil samples from the mcmurdo dry valleys of southern victoria land antarctica were studied to examine their features and to elucidate source materials normal alkanes and n alkenes were found at concentrations ranging from 13 to 2200 and from 1 1 to 5000 ng g of dry soil respectively unexpectedly the major hydrocarbons were all odd carbon numbered long chain n alkanes with maximum concentrations n c 23 n c 25 or n c 27 this may be due to the erosion of sedimentary materials containing vascular plant debris formed during the pre and inter glaciation periods of antarctica miocene pliocene and microbial debris such as fungi and microalgae normal alkenes maximize at n c 23 1 carbon chain length number of double bonds n c 25 1 n c 27 1 or n c 29 2 which could be derived from cyanobacteria and microalgae that lived in the past in the antarctic cold desert and or organic debris of wind transported cyanobacterial mats

the interaction of simulated squall lines with idealized mountain ridges abstract numerical simulations of squall lines traversing sinusoidal mountain ridges are performed using the advanced regional prediction system cloud resolving model precipitation and updraft strength are enhanced through orographic ascent as a squall line approaches a ridge the simulated squall line then weakens as it descends the ridge because some of the cold pool is blocked by the terrain resulting in less lift along the gust front and weaker convective cells the flow within the cold pool accelerates slightly and the depth of the cold air decreases owing to upstream blocking transitioning the flow in the cold pool head from subcritical to supercritical then back to subcritical at the bottom of the ridge a hydraulic jump forms when the flow transitions the second time enabling the development of a new convective line downwind of the mountain these new updrafts grow and eventually replace the older updrafts that weakened during descent this process results in the discrete propagation of a squ

polyphase seismic faulting in the ivrea zone italian alps revealed by 40ar 39ar dating of pseudotachylytes terra nova 23 162 170 2011 abstract most fault related pseudotachylytes in the val sesia area ivrea zone nw italian alps occur in two areas near the canavese line in the kinzigite formation paragneisses and in an elongate belt in the mafic complex gabbros away from the canavese line 40ar 39ar dating indicates that pseudotachylytes from the kinzigite formation were formed in the late eocene likely during the early stages of the collision between the nw corner of the adriatic indenter and the european margin pseudotachylytes from the mafic complex were formed under a transpressive strain regime as suggested by kinematic indicators and yield early cretaceous albian 40ar 39ar ages their formation is possibly related to shortening during the inception of the tectonic inversion of the adriatic passive margin

coal as a source rock for oil a review the geological debate about whether and to what extent humic coals have sourced oil is likely to continue for some time despite some important advances in our knowledge of the processes involved it is clear that not only liptinites but also perhydrous vitrinites have the potential to generate hydrocarbon liquids in the course of natural coalification some liptinites especially alginite cutinite and suberinite contain a higher proportion of aliphatic moieties in their structure than other liptinites such as sporinite and resinite and are therefore more oil prone it is of potential value to be able to predict the several environments of deposition in which coals with high liptinite contents or containing perhydrous vitrinites may have been formed review of the distribution of oil prone coals in time and space reveals that most are jurassic tertiary with key examples from australia new zealand and indonesia methods based both on experimental simulations and the examination of naturally matured samples have been used to determine the order of generation of hydrocarbons from different macerals results are not entirely consistent among the different approaches and there is much overlap in the ranges of degradation but it seems probable that in the natural environment vitrinites begin to generate early followed by labile liptinites such as suberinite then cutinite sporinite and finally alginite petroleum potential may be determined by experimental simulation of natural coalification or inferred through various micro techniques especially fluorescence and infrared ir spectroscopy or bulk techniques such as elemental analysis and 13c nmr spectroscopy the latter three techniques enable a measure of the polymethylene component of the coal which now appears to be one of the best available approaches for determining petroleum potential no method of experimental simulation of petroleum generation from coals is without criticism and comparative results are highly variable however hydrous pyrolysis confined pyrolysis and forms of open system hydrous pyrolysis approach acceptable simulations whether and to what degree generated liquid hydrocarbons are expelled has long been the central problem in oil from coal studies the structure of vitrinite was believed until recently to contain an interconnected microporous network in which generated oil would be contained until an expulsion threshold was attained recent studies show the pores are not interconnected combined with a dynamic model of pore generation it now seems that expulsion of hydrocarbons is best explained by activated diffusion of molecules to maceral boundaries and ultimately by cleats and fractures to coal seam boundaries the main reason for poor expulsion is the adsorption of oil on the organic macromolecule which may be overcome 1 if coals are thin and interbedded with clastic sediments or 2 if the coals are very hydrogen rich and generate large quantities of oil the existence of oil in vitrinite is attested to by solvent extractions fluorescence properties and by microscopic observations of oil and bitumen experimental simulation of expulsion of oil from coals has only recently been attempted the relative timing of release of generated co2 and ch4 could have considerable importance in promoting the expulsion of liquid hydrocarbons but the mechanism is unclear as it is universally agreed that dispersed organic matter dom in some shales readily generates and expels petroleum it is curious that few consistent geochemical differences have been found between coal macerals and dom in interbedded shales unambiguous evidence of expulsion from coals is limited and in particular only a few commercial oil discoveries can be confidently correlated to coals these include upper cretaceous fruitland formation coals in the usa from which oil is produced new zealand tertiary coals and middle jurassic coals from the danish north sea it is likely that coals have at least contributed to significant oil discoveries in the gippsland basin australia in the turpan basin china and in the kutei and ardjuna basins in indonesia but this remains unproven early reports that early jurassic coals in mid norway were a major source of the reservoired oils have been shown to be inaccurate none of the proposed rules of thumb for generation or expulsion of petroleum from coals seem particularly robust decisions on whether a particular coal is likely to have been an active source for oil should consider all available geological and geochemical information the assumptions made in computational models should be well understood as it is likely with new understandings of processes involved that some of these assumptions will be difficult to sustain

organic facies and depositional palaeoenvironment of lignites from rio maior basin portugal abstract the rio maior basin portugal is a tectonic depression filled by a pliocene sequence that comprises from floor to roof i kaoliniferous fine sands ii diatomites and lignites iii recent deposits of sandstone and clay the diatomites and lignites form a small dissimetric syncline with alternating seams ten lignite seams were identified and named from floor to roof as f e d c 2 c 1 c b a a and a seams a d e and f are considered to be the main seams the organic fraction consists mainly of macerals of the huminite group with small percentages of inertinite and liptinite groups however the petrographic composition of each seam is distinct particularly with regards to macerals of the huminite and liptinite groups calculation of petrographic indices permitted to plot the coals in facies and palaeoenvironment diagrams five facies have been defined i aquatic ii herbaceous swamp iii mixed swamp with forest and herbaceous vegetation vi forest swamp wetter and v forest swamp drier these lignites are humic coals formed from organic matter of terrestrial origin the peat biomass at the origin of these coals formed from a very diverse vegetation comprising gymnosperms and angiosperms in seams f and occasionally in seams e and d botryococcus algae have also contributed to the biomass peat deposition corresponded to a rheotrophic hydrological regime the water level always remained above the topographic surface of the basin nevertheless during the deposition of seam a in the northern part of the basin the water level was slightly below the topographic surface the organic matter was preserved in anaeorobic conditions

estimation of lignite reserve in the kalburcayiri field kangal basin sivas turkey abstract this paper addresses a case study on global estimation of lignite reserve in the kalburcayiri field from the sivas kangal basin which is one of the most productive lignite basins in eastern anatolia turkey the two lignite seams which were developed in a fresh water lacustrine depositional environment during the pliocene time are currently being exploited in the kalburcayiri open cast mine for feed coal to a power plant with 300 mw capacity tonnage thickness and quality parameters ash yield total sulphur content and calorific value of the lignite are variables considered in this study the global estimates of these variables together with 95 confidence limits are obtained using the approximation principle of global estimation a random stratified grid is fitted to available boreholes the variograms for thickness and lignite quality parameters are estimated and modeled the models are used in calculating estimation error variances that will later be used in constructing 95 confidence intervals for the true values

oil generating coals of the san juan basin new mexico and colorado u s a abstract coal beds of the upper cretaceous fruitland formation in the san juan basin of northwestern new mexico and southwestern colorado have significant liquid hydrocarbon generation potential as indicated by typical rock eval hydrogen indexes in the range of 200 400 mg hydrocarbon g organic carbon type ii and iii organic matter small non commercial quantities of oil have been produced from the coal beds at several locations the oils are characterized by high pristane phytane ca 4 and pristane n c17 ratios ca 1 2 abundant c21 alkanes in the c10 fraction with a slight predominance of odd carbon numbered n alkanes abundant branched chain alkanes in the c15 region and a predominance of methylcyclohexane in the c4 c10 fraction the oils are indigenous to the fruitland formation coals and probably migrated at thermal maturities corresponding to vitrinite reflectance values in the range 0 7 0 8 although the oils found to date are not present in commercial amounts these findings illustrate the potential of some coals to generate and expel oil under conditions of moderate thermal heating

significance of coniferous rain forests and related organic matter in generating commercial quantities of oil gippsland basin australia contrary to the conventional belief that humic coal generates primarily gas 3 billion bbl of recoverable oil has been discovered in the humic coaly succession of the fluviodeltaic latrobe group upper cretaceous tertiary that serves as both the reservoir and the source for hydrocarbons in the offshore gippsland basin of southeastern australia evidence for generation of liquid hydrocarbons from the coaly succession includes 1 similarity of n alkane distribution in the oil and in the coal extracts 2 high wax content of oil up to 27 by weight 3 high ratio of pristane phytane in oil 5 6 and 4 dominance of c29 steranes in the oil in the gippsland basin coniferous rain forests dominated by kauri vegetation flourished in a raised bog setting present temperate climate and kauri vegetation of new zealand are considered to be the modern analog to the gippsland basin the coniferous vegetation provided large quantities of hydrogen rich exinite macerals such as cutinite and resinite with potential to generate oil high rainfall raised ground water level low oxygen high acidity and low nutrient conditions of a raised bog setting were suitable for preserving organic matter a comparison of gas chromatograms of oils in the gippsland basin with gas chromatograms of oils generated by hydrous pyrolysis in the laboratory from the immature source rocks suggests that the paraffinic fraction of the oil was derived from coal and the naphthenic fraction was derived chiefly from resin

trace elements in the lower pliocene fossiliferous kangal lignites sivas turkey abstract the kangal lignite basin which is one of the most productive lignite basins in eastern anatolia turkey includes two lignite seams containing abundant gastropoda shells in the lower pliocene kalburcayiri formation the seams are currently exploited in an open cast mine in the kalburcayiri field and supply feed coal to a power plant with 300 mw capacity the average thickness of each of the two seams in this mine is about 10 m and they are separated by about 20 m of tuffaceous sedimentary rocks a 15 20 cm thick tuff bed occurs within the upper seam the purpose of the study was to understand mineralogy and trace element concentrations of the two lignite seams in the kalburcayiri formation which were affected by volcanic ashes fifty nine core samples of the lignites from seven boreholes across the basin and eight channel samples from the working lignite seams were collected and analysed by proximate analysis x ray powder diffraction xrd inductively coupled plasma mass spectrometry icp ms and scanning electron microscopy sem with energy dispersive x ray microanalysis techniques the samples show that the worked lignite seams on an as received basis contain high moisture contents 43 4 57 8 all the samples on an air dried basis have high ash yields from 19 5 to 81 7 and a broad range of total sulfur contents from 1 16 to 7 04 and calorific values 684 to 4621 kcal kg except for two samples with no temperature rise due to high ash yield the mineral matter of the studied samples is made up of calcite quartz feldspar pyrite opal ct clay minerals gypsum and traces of aragonite the trace element analyses on a whole coal dry basis indicate that most of the borehole samples showed enrichment in specific elements including zn 15 1394 g g mo 13 368 g g and u 5 5 131 g g when compared to the range of these elements for most coals in the world the contents of zn mo and u for the samples from the worked lignite seams are respectively 38 187 54 161 and 28 55 g g the sem studies show that zn is hosted mainly in micron sized zn bearing mineral sphalerite but no mo and u bearing minerals have been detected during these studies except for monazites containing th and u traces the mo and u concentrations are negatively correlated with the ash yields and these elements are contained mainly within organic matter

guidelines for evaluating petroleum source rock using programmed pyrolysis rock eval pyrolysis is used to rapidly evaluate the petroleum generative potential and thermal maturity of rocks accurate conclusions require programs every 30 60 ft 9 18 m understanding of interpretive pitfalls and supporting data such as visual kerogen vitrinite reflectance and elemental analyses the generative potential of coals is commonly overestimated by pyrolysis and is best determined by elemental analysis and organic petrography most coals show high s2 s3 5 and low hi values 300 mg hc g toc migrated oil and mud additives which alter rock eval data can sometimes be removed by special processing for immature rocks bimodal s2 peaks and pi values over 0 2 indicate contamination pyrolysis downgrades organic poor clay rich rocks which show lower hi and higher tmax values than isolated kerogen because of adsorption of pyrolyzate on the clays tmax values for small s2 peaks 0 2 mg hc g toc are unreliable tmax is affected by maturation organic matter type contamination and the mineral matrix s3 is sensitive to inorganic and adsorbed carbon dioxide and to instrumentation problems acidification of carbonate rich samples and proper maintenance improves s3 measurement constant sample weights 100 mg are recommended below a threshold weight tmax increases by up to 10 c and other parameters decrease organic rich samples which overload the detector can be diluted with carbonate detector linearity is determined by pyrolyzing various weights of an organic rich rock

hydrocarbon generation potential and miocene pliocene paleoenvironments of the kangal basin central anatolia turkey abstract this study deals with the organic geochemical characteristics hydrocarbon generative potential and miocene pliocene paleoenvironments of the kangal coal district which developed in a limnic depositional environment and contains the hamal etyemez and kalburcayiri coal fields in the southern part of the sivas basin central anatolia around kalburcayiri the average thickness of each of the two coal seams approximately 10 m are currently being exploited based on open cast methods the coal from which is used by the nearby lignite fired kangal power station an attempt was made to elucidate depositional conditions through proximate and ultimate analyses coal petrography and the geochemical characteristics of the kangal coals these coals have a huminite reflectance value of rmax 0 40 accordingly from the standpoint of coal rank this is a dull brown coal of the subbituminous c type huminite is the most widespread maceral type while gelinites are the most often encountered macerals relative to liptinites the proportion of inertinites is high on the basis of maceral composition the depositional environment of the kangal coals was determined to be either a forest swamp or a lake bottom the distributions of the c27 and c28 c29 steranes for all these coal samples are very similar c29 c27 c28 tricyclic terpanes have low concentrations in all samples of the kangal coals and are dominated by low molecular weight compounds c20 c24 with a maximum at c23 total organic carbon toc wt values of the kalburcayiri samples are 4 64 30 64 wt in the hamal samples 0 83 2 53 wt and in the etyemez samples 8 91 10 39 wt on the basis of tmax values the samples are in the immature early mature stage according to rock eval pyrolysis data the coals have hydrocarbon source rock potential but the coaly shales and other organic matter rich levels have no hydrocarbon source rock potential the high inertinite levels and high vitrinite inertinite ratios suggest that the kangal coals have more potential for gas generation than oil

relationships between coal quality and organic geochemical parameters a case study of the hafik coal deposits sivas basin turkey abstract this study provides coal quality organic petrographic and organic geochemical data on tertiary subbituminous coal of the hafik area northwestern part of the sivas basin turkey coal petrological studies along with proximate and ultimate analyses were undertaken to determine the organic petrographic characteristics of the hafik coals huminite reflectances were found to be between 0 38 and 0 48 corresponding to an organic material rich and coal layers values characteristic of low maturity this parameter shows a good correlation with calorific values average 21 060 kj kg and average t max 422 c mineral matter diagenesis indicating immaturity the studied coals and organic material underwent only low grade transformation a consequence of low lithostatic pressure therefore the hafik coals are actually subbituminous in rank rock eval analysis results show types ii iii and iii kerogens the organic fraction of the coals is mostly comprised of humic group macerals gelinites with small percentages derived from the inertinite and liptinite groups in this study organic petrographic organic geochemical and coal quality data were compared the hafik deposit is a high ash high sulfur coal the mineral matter of the coals is comprised mainly of calcite and clay minerals

influence of geochemical organo petrographical and palynofacies assemblages on hydrocarbon generation a study from upper oligocene coal and shale of the makum coal basin assam india abstract the makum coal basin of northeast india comprises important coal and shale reserves of upper oligocene age a total of twenty samples were collected to evaluate the kerogen type hydrocarbon generation potential and thermal maturity through geochemically organo petrographically and palynofacies analyses the samples are characterized by high toc total organic carbon and large s2 remaining heavier hydrocarbons meet the required standards as good to excellent generation potential the coal and shale are marked by mixed type iii ii kerogen with minor occurrence of type i kerogen moderate to high hydrogen index hi values and are considered to generate thermogenic gas with some condensate oil the reflectance values indicate samples are mostly immature and close to the oil birth line the amount of vt60 grains also suggests that the samples can produce some condensate oil along with thermogenic gas the rock eval pyrolysis rep data stands with the interpretation through petrographic palynofacies and fourier transform infrared spectroscopy ftir in determining kerogen type and generation potential the generation potential is also controlled by the degree of organic matters reactivity the estimated reactivity indicates that besides vitrinite and liptinite up to 70 vol of the inertinite macerals have the potential to generate hydrocarbon the occurrence of a substantial amount of reactive macerals i e collotelinite vitrodetrinite collodetrinte corpogelinite alginite resinite and bituminite within the samples makes them more potential to generate hydrocarbons the diagram proposed based on our data of macerals and palynofacies assemblages may also be a convenient tool in detecting kerogen type s and nature of hydrocarbons

characterisation of oil and potential source rocks in the northeastern song hong basin vietnam indications of a lacustrine coal sourced petroleum system oil discovered in the b10 stb 1x well in the northeastern song hong basin vietnam has typical lacustrine coaly geochemical features indicating the existence of a principally lacustrine sourced petroleum system with minor contributions from a coal source the presence of lacustrine source rocks in the basin is indicated by distinct high amplitude seismic reflectors in undrilled half grabens and outcrops of oligocene immature mudstones and humic coals at dong ho and on bach long vi island the mudstones from dong ho generally have a toc content of 8 17 wt and hi values 500 mg hc g toc the organic matter is principally composed of fluorescing amorphous organic matter and liptodetrinite alginite with botryococcus morphology is present the organic matter corresponds to type i kerogen the bach long vi island mudstones contain 2 7 wt toc and have hi values from 200 700 mg hc g toc the organic matter is largely similar to that in the dong ho mudstones but in addition may contain some marine organic material the b10 stb 1x oil shows features common to both the dong ho and bach long vi island mudstones but was probably principally generated from a source similar to the dong ho mudstones with contributions from higher land plant organic matter a prominent activation energy peak dominates the activation energy distributions of the mudstones and upon artificial maturation hydrous pyrolysis the mudstones show extensive hydrocarbon generation over a narrow temperature range hydrocarbon expulsion has been estimated to occur at a vitrinite reflectance of 0 75 ro the source of the b10 stb 1x oil may be located in the thuy nguyen graben and maturity modelling shows that the lacustrine mudstones will be thermally mature in this graben

geochemical and palynological investigation of the shengli river marine oil shale china implications for paleoenvironment and paleoclimate abstract the shengli river oil shale located in the north qiangtang depression northern tibet plateau represents a potential large marine oil shale resource in china a geochemical and palynological investigation of the oil shale was performed to reconstruct paleoenvironment and paleoclimate during deposition the total organic carbon toc contents 15 05 20 34 and s 2 values 103 27 129 12 mg hc mg rock of oil shale samples are high and the organic matter consists mainly of type ii kerogen the thermal maturity assessed from pi 0 033 0 036 and t max 433 436 shows an immature to early mature stage of the organic matter analyzed oil shale samples from the shengli river area are characterized by a dominance of low carbon number molecular compositions with high c 21 c 21 2 10 2 83 low pr ph 0 63 0 75 and high concentrations of c 27 sterane and homohopanes c 31 c 35 indicating reducing environments highly saline conditions and a prevalent contribution of algae to organic matter accumulation the analyzed oil shale samples have an uncommonly heavy c isotopic composition ranging in 13 c values of bulk organic matter from 20 79 to 21 78 the enrichment in 13 c is mainly attributed to the high productivity of algae rather than solely the result of hypersalinity composition of palynofloras from oil shale samples suggests that the climate of the qiangtang basin region during the deposition of oil shales was warm and humid or sub humid

comparative study between rock eval pyrolysis and biomarkers parameters a case study of ypresian source rocks in central northern tunisia abstract sedimentary rock samples from the ypresian basin in central northern tunisia were analyzed by two well proven organic geochemical methods rock eval re pyrolysis and gas chromatography mass spectrometry gc ms analysis these techniques were uses to obtain independent parameters on organic matter composition its thermal maturity and environment of deposition this study reveals a close concordance between rock eval pyrolysis data and polycyclic biomarkers parameters such as hopanes and steranes re pyrolysis in conjunction with gc ms analysis show that the ypresian basin sediments contain a variable but notable organic rich facies during the ypresian and prove an unequivocal evidence for type ii organic matter which lies dominantly prior to the peak stage of the conventional oil window end of diagenesis beginning of catagenesis the case study from the ypresian basin shows that these methods remain undoubtedly suitable for a good assessment of the petroleum potential of source rocks and rapid geochemical characterization of sedimentary organic matter

pliocene lignites from apofysis mine amynteo basin northwestern greece petrographical characteristics and depositional environment coal petrological investigation along with proximate and elemental analyses were undertaken to determine the petrographic characteristics of the apofysis lignites amynteo basin northwestern greece and their depositional environment eight samples representing different lignite beds of the apofysis deposit were collected from a borehole the apofysis lignites have an eu ulminite b reflectance of rr 0 22 and in terms of lithotype belong to matrix soft brown coals huminite is the most abundant maceral group and consists mostly of humodetrinite inertinite has relatively low percentages whereas liptinite concentrations are low in the lower lignite beds and higher in the upper ones ternary plots and facies indices were employed in order to investigate the palaeoenvironment the depositional environment of the apofysis lignites is not definitely ascribed to a forest swamp or a reed marsh environment the high ash content of the analysed samples is a clear indication of a topogenous setting low tissue preservation index tpi and high gelification index gi values are observed high alkalinity and strongly reducing conditions may be inferred from the presence of syngenetic framboidal pyrite the low tpi values which indicate high bacterial activity and thus high ph conditions and the preservation of gastropod shells and chlorophyllinite high gi indicates a constant influx of calcium rich waters into the coal swamp the apofysis lignite deposit may be interpreted to be autochthonous to hypoautochthonous the peat accumulation was governed by a high groundwater level wet telmatic to limno telmatic facies and a moderate subsidence rate

characterization of mangrol lignite gujarat india petrography palynology and palynofacies a multidisciplinary approach petrographical palynological and palynofacies has been adopted to characterize and assess the depositional conditions of eocene mangrol lignite deposit from western india the petrographic study reveals that the lignite is composed predominantly of huminite macerals produced from a woody forest the reflectance values range from 0 27 to 0 32 indicating a lignite rank the variable values of tissue preservation index tpi and gelification index gi as well as the maceral composition indicate fluctuating ground water conditions and difference in the type of vegetation during peat accumulation the palynofloral spectrum suggests the presence of angiosperms including mangrove and pteridophytes belonging to families of bombacaceae annonaceae alangiaceae ctenolophonaceae liliaceae osmundaceae schizaeaceae matoniaceae cyatheaceae among others as the peat biomass source materials for the origin of these lignites the palynomorphs indicate that a tropical to sub tropical climatic condition was present during deposition of the peat biomass and that the original mire likely occurred in a coastal setting this interpretation is strongly supported by palynomorphs with affinity to brackish water taxa palynofacies studies suggest peat deposition under dysoxic conditions in a marginal marine setting high amount of amorphous matter kerogen type i in the shale bed above the lignite and very high content of liptinite in lignite mainly comprised of resinite and liptodetrinite suggest the potential of both shale and lignite for the generation of hydrocarbon

hydrocarbon genesis of jurassic coal measures in the turpan basin china abstract a typical case of coal derived oils in china i e the crude oils from the middle lower jurassic coal measure strata in the turpan basin is presented by means of oil source correlation it is confirmed that low maturity crude oil in the shengjinkou oil field is derived from the coal bearing qiketai formation of middle jurassic age a brackish lacustrine sediment mature crude oils in the qiketai oil field and in well taican 1 are sourced from the badaowan formation of lower jurassic age which contains coal seams as thick as 100 m results show that commercial accumulations of liquid crude oils can be generated from coals and coal measure strata containing high volatile coal of bituminous rank despite unfavourable types of source material the total hydrocarbon generating potential can be great due to the unusual abundance of organic matter

the petroleum generation potential and effective oil window of humic coals related to coal composition and age abstract a worldwide data set of more than 500 humic coals from the major coal forming geological periods has been used to analyse the evolution in the remaining hydrogen index hi and total quality index qi generation potentials with increasing thermal maturity and the effective oil window oil expulsion window all samples describe hi and qi bands that are broad at low maturities and that gradually narrow with increasing maturity the oil generation potential is completely exhausted at a vitrinite reflectance of 2 0 2 2 ro or tmax of 500 510 c the initial large variation in the generation potential is related to the original depositional conditions particularly the degree of marine influence and the formation of hydrogen enriched vitrinite as suggested by increased sulphur and hydrogen contents during initial thermal maturation the hi increases to a maximum value himax similarly qi increases to a maximum value qimax this increase in hi and qi is related to the formation of an additional generation potential in the coal structure the decline in qi with further maturation is indicating onset of initial oil expulsion which precedes efficient expulsion liquid petroleum generation from humic coals is thus a complex three phase process i onset of petroleum generation ii petroleum build up in the coal and iii initial oil expulsion followed by efficient oil expulsion corresponding to the effective oil window efficient oil expulsion is indicated by a decline in the bitumen index bi when plotted against vitrinite reflectance or tmax this means that in humic coals the vitrinite reflectance or tmax values at which onset of petroleum generation occurs cannot be used to establish the start of the effective oil window the start of the effective oil window occurs within the vitrinite reflectance range 0 85 1 05 ro or tmax range 440 455 c and the oil window extends to 1 5 2 0 ro or 470 510 c for general use an effective oil window is proposed to occur from 0 85 to 1 7 ro or from 440 to 490 c specific ranges for himax and the effective oil window can be defined for cenozoic jurassic permian and carboniferous coals cenozoic coals reach the highest himax values 220 370 mg hc g toc and for the most oil prone cenozoic coals the effective oil window may possibly range from 0 65 to 2 0 ro or 430 to 510 c in contrast the most oil prone jurassic permian and carboniferous coals reach the expulsion threshold at a vitrinite reflectance of 0 85 0 9 ro or tmax of 440 445 c

characterization of turkish coals a nationwide perspective abstract the u s geological survey usgs and the turkish general directorate of mineral research and exploration maden tetkik ve arama genel mudurlugu mta are working together to provide a better understanding of the chemical properties of turkish coals from major turkish lignite producing areas the coals in turkey are generally low rank lignite or subbituminous formed in several different depositional environments at different geologic times and have differing chemical properties eocene coals are limited to northern turkey oligocene coals found in the thrace basins of northwestern turkey are intercalated with marine sediments miocene coals are generally located in western turkey the coal deposits which have limnic characteristics have relatively abundant reserves pliocene pleistocene coals are found in the eastern part of turkey most of these coals have low calorific values high moisture and high ash contents analysis of 143 coal channel samples most are lignite and subbituminous in rank but a few are bituminous and one is anthracitic in rank has been completed for up to 54 elements and other coal properties using a variety of analytical techniques including inductively coupled plasma emission and mass spectrometry instrumental neutron activation analysis and various single element techniques and astm standard procedures many of these coals have elemental concentrations similar to u s lignites found in the gulf coast and fort union regions however maximum or mean concentrations of b cr cs ni as br sb cs and u in turkey are higher than the corresponding maximum or mean values found in either the fort union or gulf coast regions

investigation on the lignite deposits of surkha mine saurashtra basin gujarat western india their depositional history and hydrocarbon generation potential abstract an integrated approach is adopted to study the lignite deposits of surkha mine associated with the khadsaliya clays formation eocene of saurashtra basin western india the compilation of detailed investigation includes organic petrographical palynofacies and geochemical analyses the type and amount of organic matter and its relation to palaeoenvironmental conditions have been determined and discussed along with its significance as hydrocarbon source the macerals of huminite group show dominance av 61 over the liptinite and inertinite groups the petrographical indices gi tpi gwi vi indicate wood dominated precursors of peat were deposited in limno telmatic to telmatic regime under mesotrophic hydrological conditions in palynofacies analysis it is observed that the particulate organic matter is dominated by the phytoclasts group av 69 followed by the amorphous organic matter aom and palynomorphs the biomarker signatures show angiosperm and gymnosperm source vegetation the presence of sesquiterpenoids indicate the occurrence of dipterocarpaceae flora suggesting the existence of rain forest vegetation in the vicinity of depositional site the kaurane type of diterpenoids suggest the presence of conifers among the source flora the extrapolation of organic matter data on tyson s app diagram along with the pr n c 17 vs ph n c 18 plot indicate that the deposition took place in dysoxic suboxic conditions with intermittent shifting of the environment in proximal settings the huminite reflectance values av 0 31 r r show a good correlation with gross calorific values av 3917 cal g and average t max value 416 c of the lignites furthermore the abundance of thermally unstable hop 17 21 ene and hopane indicate immature stage of lignites these lignites contain high toc av 35 wt and low ash yields the volatile matter carbon and oxygen contents are relatively high whereas sulphur content is moderate and hydrogen and nitrogen contents are comparatively low in all the lignite samples the hydrogen index values vary between 53 and 538 mg hc g toc the atomic values of h c range from 0 47 to 1 04 and of o c from 0 20 to 0 29 overall the lignite bearing sequence is characterized by type ii iii admixed kerogens organic matters and has potential to generate hydrocarbons upon maturation

molecular organic geochemistry of the tarim basin northwest china we conducted organic geochemical analyses on the largest suite of oils and source rock extracts from the tarim basin northwest china currently available statistical cluster analysis of the entire suite of tarim oils distinguishes at least seven genetic groups of oils the largest group of oils was collected from the tazhong and tabei uplifts and originated from marine middle upper ordovician anoxic marls that mark slope facies at the margins of structural uplifts two other genetic groups most likely originated from marine middle upper ordovician source rocks but of distinct facies with one an oxic shale rich source west of the bachu uplift and the other an anoxic shale source at tazhong

compound specific stable carbon isotope analysis as a tool for correlating coal sourced oils and interbedded shale sourced oils in coal measures an example from turpan basin north western china molecular geochemical methods have shown that it is often diacult to diaerentiate between coal and interbedded shale sourced oils even though coals and interbedded shales may exhibit considerable organic influx variation e g land plant vs algal organic matter due to the changes of depositional setting however compound specific stable carbon isotopic compositions are sensitive to the source input variations typically specific molecules are more depleted in 13 c with increasing content of aqueous biota this hypothesis is examined and exemplified by comparing the stable carbon isotopic ratios of n alkanes from source rock extracts and related oils of the turpan basin northwestern china stable carbon isotopic values of n alkanes extracted from coals and interbedded shales show that d 13 c values of n alkanes with less than 20 carbon atoms vary only slightly however there are dramatic changes in the isotopic compositions of higher molecular weight n alkanes furthermore n alkanes from coal extracts are enriched in 13 c relative to that of interbedded shales with excursions up to 2 3 this comparison enables the diaerentiation of coal and interbedded shale sourced oils and provides information useful in assessing the hydrocarbon system of a basin 2000 elsevier science ltd all rights reserved

depositional environment of the late miocene hausruck lignite alpine foreland basin insights from petrography organic geochemistry and stable carbon isotopes abstract lignites and fossil wood from two boreholes in the late miocene hausruck district alpine foreland basin austria were investigated with respect to organic carbon and total sulfur contents ash yields maceral composition organic geochemistry and stable carbon isotope ratios the lignites from the two sampled profiles differ in sulfur contents and petrography based facies indicators gelification index gi tissue preservation index tpi the results point to drier and more acidic conditions in the part of the mire sampled at drill site lukasberg whereas the lignites from kalletsberg formed under near neutral conditions due to a raised ground water table the different depositional environments are supported by the paleogeographic positions of the boreholes borehole lukasberg is located within a paleo valley whereas borehole kalletsberg is located at the deeper part of a basin situated south and southwest of the hausruck area environmental changes with time within the mire are confirmed by the molecular composition of the soluble organic matter som differences in pristane phytane ratio isomerisation of hopanes at position 17 concentrations of hopanes and in the ratio of hopanes to hop 17 21 enes are related to the extent of gelification of plant tissue sulfur content and ph values caused by differences in ground water table the variable contents of individual terpenoid hydrocarbons derived from land plants indicate that angiosperms and conifers contribute to peat formation in the hausruck district in variable proportions overall angiosperm biomarkers slightly predominate the tissue preservation index tpi within the kalletsberg profile is probably governed by the proportion of decay resistant conifers as indicated by the correlation between tpi and biomarker composition of the coals correlations between 13 c values of the lignites between 24 9 and 27 4 and their non hopanoid terpenoid composition indicate the major influence of changes in peat forming vegetation on the carbon isotopic composition of the coals in the hausruck district carbon isotope data of macrofossils are consistent with their taxonomical classification as conifers 13 c between 22 7 and 25 1 and angiosperms 13 c between 25 5 and 26 6 respectively the 13 c data of the extracted cellulose reveal clear differences between fossil wood from gymnosperms average 13 c 21 0 and angiosperms mean 13 c 23 4

petrology rank and evidence for petroleum generation upper triassic to middle jurassic coals central alborz region northern iran abstract upper triassic to middle jurassic coals from the alborz region of northern iran were analyzed by reflected light fluorescence microscopy and rock eval 6 pyrolysis to evaluate their regional rank variation degree of hydrothermal alteration and petroleum generative potential the coal ranks in the region range from a low of 0 69 ror in the glanddeh rud area to a high of 1 02 ror in the gajereh area tmax c values rock eval 6 pyrolysis also increase progressively with increasing vitrinite ro values however tmax is suppressed lower than would be expected for each rank ranging from 428 c for the glandeeh coal to 438 c for the gajereh coal tmax suppression may be caused by maceral composition and soluble organics within the coal moderately high hydrogen indices persistent and oily exudations from the coals during uv exposure and traces of hydrocarbon fluid inclusions suggest that liquid petroleum was likely generated within some of the coals

assessment of hydrocarbon source rock potential of polish bituminous coals and carbonaceous shales abstract we analyzed 40 coal samples and 45 carbonaceous shale samples of varying thermal maturity vitrinite reflectance 0 59 to 4 28 from the upper carboniferous coal bearing strata of the upper silesian lower silesian and lublin basins poland to evaluate their potential for generation and expulsion of gaseous and liquid hydrocarbons we evaluated source rock potential based on rock eval pyrolysis yield elemental composition atomic h c and o c and solvent extraction yields of bitumen an attempt was made to relate maceral composition to these source rock parameters and to composition of the organic matter and likely biological precursors a few carbonaceous shale samples contain sufficient generation potential pyrolysis assay and elemental composition to be considered potential source rocks although the extractable hydrocarbon and bitumen yields are lower than those reported in previous studies for effective type iii source rocks most samples analysed contain insufficient capacity for generation of hydrocarbons to reach thresholds required for expulsion primary migration to occur in view of these findings it is improbable that any of the coals or carbonaceous shales at the sites sampled in our study would be capable of expelling commercial amounts of oil inasmuch as a few samples contained sufficient generation capacity to be considered potential source rocks it is possible that some locations or stratigraphic zones within the coals and shales could have favourable potential but could not be clearly delimited with the number of samples analysed in our study because of their high heteroatomic content and high amount of asphaltenes the bitumens contained in the coals are less capable of generating hydrocarbons even under optimal thermal conditions than their counterpart bitumens in the shales which have a lower heteroatomic content

influence of floral assemblage facies and diagenesis on petrography and organic geochemistry of the eocene bourgas coal and the miocene maritza east lignite bulgaria abstract numerous differences in the petrography and organic geochemistry of two tertiary low rank coal deposits of bulgaria formed within comparable depositional environments are outlined different floral assemblages are indicated as the main sources of organic matter for the eocene bourgas sub bituminous coals a warm climate plant community dominated by angiosperms is reflected in the biomarker composition whereas a coniferous flora was the main source of the resinous organic matter of the miocene maritza east lignite the results are in agreement with palaeobotanical data these differences in the peat forming vegetation of the paleogene compared to the neogene of bulgaria are attributed to decreasing temperature during the tertiary the abundance of resinous compounds relative to lipids from plant waxes long chain n alkanes as well as the preservation of plant tissue are mainly controlled by gymnosperm angiosperm ratios pristane phytane and diasterenes sterenes ratios reflect variations in redox conditions and the ph of the depositional environments caused by eustatic sea level changes freshwater inflow or varying ground water table changing eh and ph values are associated with differences in microbial activity controlling the extent of gelification of plant tissue bacteria most probably contributed to the aromatisation of triterpenoids in the mire enhanced thermal maturation of organic matter during diagenesis is reflected in higher contents of n alkanes and the presence of alkyl naphthalenes in the bourgas coals alkyl naphthalenes are thought to have been formed from pentacyclic triterpenoids rather than from resinous compounds

the biogeochemical evolution of the coorong during the mid to late holocene an elemental isotopic and biomarker perspective since the mid 1990s the coorong a 130 km long coastal wetland of international importance in southeastern south australia has undergone serious decline due largely to prolonged drought and reduced inflows of surface and ground water from its hinterland tenuously connected to the ocean at its northern extremity it is effectively separated into two lagoons by a narrow channel at its mid point the southern part is now permanently hypersaline here we report the results of an attempt to track the biogeochemical status of the estuary over the last 5000 years employing a consortium of elemental isotopic and biomarker parameters the sediment samples analysed came from two cores each 6 7 m in length retrieved from sites located halfway along the present day northern and southern lagoons the sediments at the southern locality are richer in total organic carbon and total nitrogen than those in the northern core reflecting higher net deposition of organic matter om and nutrients in the southern lagoon comparison of the d 13 corg and d 15 n profiles of the two cores reveals that the lower reaches of the coorong have always been a restricted o2 depleted water body that is both more saline and prone to more intensive denitrification of no 3 aq than the northern lagoon prominent among the aliphatic hydrocarbons preserved in the sediments of the southern lagoon are the c20 highly branched isoprenoid hbi 2 6 10 trimethyl 7 3 methylbutyl dodecane a putative marker of epiphytic diatoms and c15 c35 n alkanes with a marked odd even predominance in the c21 range these and other biomarkers are consistent with om derived from a mixed population of algae cyanobacteria and other eubacteria 13 c nmr spectra confirm that this om is largely algal derived but with a significant contribution from the seagrass ruppia megacarpa and possibly other aquatic macrophytes particularly in pre european sediments the c isotopic signature of the hbi alkane is consistently heavier than those of the c23 c 25 c 27 and c29 n alkanes presumably from planktonic chlorophytes aquatic metaphytes which in turn are heavier than the coexisting even carbon numbered homologues of likely bacterial origin with decreasing age these biomarker alkanes display an overall increased depletion in 13 c and enrichment in d trends that have accelerated over recent decades as the south lagoon has become progressively more hypersaline and ecologically impoverished however coeval negative excursions in the dd profiles of the epiphyte marker and n alkanes along with coincident diatom inferred reductions in palaeosalinity together highlight a series of hitherto unrecognised freshening events attributable to enhanced inflow of surface runoff and shallow groundwater

petrographic composition and depositional environments of the pliocene velenje lignite seam slovenia abstract a pliocene lignite seam up to 160 m thick occurs in the velenje depression in northern slovenia it forms part of a non marine transgressive sequence petrographic data together with ash and sulphur content of samples from two boreholes one located in the central and the other in the marginal part of the seam have been used to study vertical and lateral coal facies variations in the central part the lignite seam overlies fluvial sediments facies critical macerals and petrographic indices suggest that the lower ash rich part of the seam unit i accumulated in a wet forest swamp in an alluvial plain setting later this environment was replaced by a dry telmatic forest swamp unit iia according to our interpretation a decrease in tree density in units iib and iic reflects a change to a bush moor the transition from unit ii to unit iii is characterized by a rapid water table rise which resulted in the establishment of a wet limnotelmatic forest swamp within unit iii the tree density decreases and the degree of gelification increases towards the top of the seam suggesting a transition to a fen type environment another rapid water table rise ended peat formation in the eutrophic topogenous mire and established open lacustrine conditions a calcium rich environment resulted in high ph values and is responsible for high sulphur lignites up to 4 on a dry basis in the upper part of the seam the ph values were controlled by the amount of the inflowing lacustrine water only thin ash rich topotelmites accumulated along the northern margin of the mire there the seam originated in a wet forest swamp and was separated by limnic and fluvial sediments from other organic rich horizons due to its closer vicinity to the pre tertiary carbonates the depositional environment was probably even more alkaline therefore the lignite shows a higher degree of gelification and is even more sulphur rich up to 5 5 on a dry basis