Weber G., Green J., ‘'Guide to oil shale'’. Heat and pressure convert organic matter into a substance called humin and then into kerogen. While the bitumen portion of oil shales is soluble in carbon disulfide, kerogen portion is insoluble in carbon disulfide and may contain iron, vanadium, nickel, molybdenum, and uranium. [4][5][7] The effect of different matrix constituents[4][5][7][8] varies from strongest to weakest: illite > Ca-bentonite > kaolinite > Na-bentonite > calcium carbonate > gypsum. The typical bacterial-algal Type II kerogen shows a small increase in hydrogen index in the immature stage (up to T max = 430°C), followed by a linear decrease, which reflects oil generation up to about T max = 465°C. Increasing production of hydrocarbons from shale has motivated a revival of research into the composition, structure, and properties of kerogen. Then transfer to the dept… Time and temperature convert kerogen into petroleum. Low content of polyaromatic nuclei and heteroatomic bonds. matter. [1] Kerogen may be classified by its origin: lacustrine (e.g., algal), marine (e.g., planktonic), and terrestrial (e.g., pollen and spores). The type of kerogen present determines source rock quality. Kerogen. gen type and thermal maturity during petroleum generation. Tissot, B. P., and D. H. Welte, 1984, Petroleum Formation and Occurrence, 2 ed. Its chemical composition varies substantially between and even within sedimentary formations. ... Organics to petroleum - zooplankton; 'sapropel'; fats, resinous, waxy. Waples used the hydrogen index values (HI) to differentiate between the types of organic matter. The more oil prone a kerogen, the higher its quality. Type IV Kerogen. During diagenesis, large biopolymers from, e.g., proteins and carbohydrates in the original organic matter decompose partially or completely. General composition of oil shales constitutes inorganic matrix, bitumens, and kerogen. The Petroleum System 11. Much of the porosity in these shales is found to be hosted within the kerogen, rather than between mineral grains as occurs in conventional reservoir rocks. NMR experiments have found that carbon in kerogen can range from almost entirely aliphatic (sp3 hybridized) to almost entirely aromatic (sp2 hybridized), with kerogens of higher thermal maturity typically having higher abundance of aromatic carbon. Sub-bituminous. [22] Similarly, sulfur speciation can be investigated with X-ray absorption near edge structure (XANES) spectroscopy, which is sensitive to sulfur-containing functional groups such as sulfides, thiophenes, and sulfoxides. Three Types of Kerogen . Ocean or lake material deposited under anoxicconditions often form kerogens of type I or II. Analyses of kerogen are generally performed on samples prepared by acid demineralization with critical point drying, which isolates kerogen from the rock matrix without altering its chemical composition or microstructure.[6]. [29][30][31] This evolution is consistent with the change in carbon speciation from predominantly aliphatic (similar to wax, density < 1 g/ml) to predominantly aromatic (similar to graphite, density > 2 g/ml) with increasing thermal maturity. Sapropelic kerogen is formed through Petroleum generating source rocks can be lacustrine, marine shale, marine carbonate or terrigenous/coaly, generally corresponding to Type I, Type II, Type II-S and Type III kerogen based on source rock screening data (Rock-Eval pyrolysis and TOC determination) plotted in modified van Krevelen diagrams. Geological burial processes cause clays to undergo physical and chemical alteration usually preceding the slow and systematic thermal conversion (generation) of kerogen to petroleum. the source rock is also the reservoir rock). ... clay types and maturation , kerogen type and maturation, permeability, porosity, and saturation. 2 assesses these conclusions). For example, the skeletal density of kerogen increases from approximately 1.1 g/ml at low thermal maturity to 1.7 g/ml at high thermal maturity. Four basic types of kerogen are found in sedimentary rocks. Only two types of organic matter are found in rocks: land derived and aquatic algae derived. [8] Thus, kerogen controls much of the storage and transport of oil and gas in shale. 1. The most significant difference is in the depth to the onset of oil generation, where 1000 m3,280.84 ft separates the top of the oil windows of these two kerogen types. The table below lists and defines these four basic kerogen types. The source rocks used in this study contain the major kerogen types, including Type-I, -II, -IIS, and -III. The name "kerogen" was introduced by the Scottish organic chemist Alexander Crum Brown in 1906,[2][3][4][5] derived from the Greek for "wax birth" (Greek: κηρός "wax" and -gen, γένεση "birth"). [7] These resulting units can then polycondense to form geopolymers. In its pure form, it is composed of vitrinite, a maceral formed from land plant wood. When heated to the right temperatures in the earth's crust, (oil window c. 50–150 °C, gas window c. 150–200 °C, both depending on how quickly the source rock is heated) some types of kerogen release crude oil or natural gas, collectively known as hydrocarbons (fossil fuels). The differences among them are related to the nature of the original organic matter. IR spectroscopy is sensitive to carbon-oxygen bonds such as quinones, ketones, and esters, so the technique can also be used to investigate oxygen speciation. This page has been accessed 95,211 times. These terms (diagenesis, catageneis, and metagenesis) are the stages in the progressive transformation of organic matter to hydrocarbon. These changes occur in hydrous environments, which probably reduce the reactive capabilities of clays, usually before significant hydrocarbon generation has occurred. In organic petrography, the different components of kerogen can be identified by microscopic inspection and are classified as macerals. Oil shale contains a lower percentage of organic matter than coal. Tissot & Welte 1978; Selley 1985). Kerogen type IV is a term not universally employed by organic geochemists because it is difficult to distinguish type IV from type III using only Rock-Eval pyrolysis. Complementary and consistent results have been obtained with infrared (IR) spectroscopy, which show that kerogen has higher fraction of aromatic carbon and shorter lengths of aliphatic chains at higher thermal maturities. Types I and II are referred to as sapropelic kerogen, and type III is known as hu-mic kerogen. One technique is 13C NMR spectroscopy, which measures carbon speciation. Kerogen type I is concentrated in condensed sections where detrital sediment transport is low and primarily pelagic. Nakamura, T. (2005) "Post-hydration thermal metamorphism of carbonaceous chondrites". Kerogen takes on additional importance in unconventional resources, particularly shale. 1. a) Explain the basic components of organic matter in sediments and different types of Kerogen in petroleum products. 1. Comprising mainly lipid materials, mainly aliphatic chains. Rock Eval analysis using hydrogen index (HI) and oxygen index (OI), Kerogen type and quality: visual assessment, Relationships between maturity and hydrocarbon generation, Open- vs closed-system generation modeling, Three common source rock evaluation errors made by geologists during prospect or play appraisals, Role of mineral matrix in kerogen pyrolysis: Influence on petroleum generation and migration, Source rock evaluation by pyrolysis-gas chromatography, Guidelines for evaluating petroleum source rocks using programmed pyrolysis, Interpreting Rock-Eval data using graphs of pyrolizable hydrocarbons vs. total organic carbon, https://wiki.aapg.org/index.php?title=Kerogen&oldid=25013, Critical elements of the petroleum system, Source and Migration Processes and Evaluation Techniques, Petroleum Source Rocks and Organic Facies. Lignite. Washington D.C. USA.p. Metagenesis- Occurs at 250ºC right when the kerogen is going to change into oil or gas. organic. Kerogen types. [1] It is insoluble in normal organic solvents because of the huge molecular weight (upwards of 1,000 daltons) of its component compounds.The soluble portion is known as bitumen.When heated to the right temperatures in the Earth's crust, (oil window ca. Amorphous kerogens are by far the most prevalent and include most of the algal material. Kerogen is the organic matter that are deposited, it can be made up of different types. This type is either mainly derived from algal lipids or from organic matter enriched in lipids by microbial activity. Before enumerating the criteria for discriminating kerogen types, it is important to consider the "mineral matrix effect." Kerogen types ~ Learning Geology. Kerogen is a complex mixture of organic chemical compounds that make up the most abundant fraction of organic matter in sedimentary rocks. As with other intermediate kerogen types, however, various maceral mixtures or degradational processes can contribute to kerogen type III formation. Type II kerogen is principally derived from marine organic materials, which are deposited in reducing sedimentary environments. Three main types of kerogen can be recognized (Figures 6):-Type I kerogen. For example, organic matter formed in different provenances can be combined, such as when planktonic algal material falls into sediments containing transported woody macerals (kerogen type III). Hydrocarbon C and H are the components that make up different types of fuel example oil, gas and coal. Some examples of pure assemblages with type I kerogen properties include the following: (1) the lacustrine alga Botryococcus braunii, which sometimes retains its diagnostic cup-and-stalk colonial morphology and/or its unique chemical compound, botryococcane;[13] (2) Tasmanites spp., which are low-salinity, cool water, marine algal phyto-plankton with unique physical features;[14] and (3) the Ordovician marine organic-walled colonial microfossil Gloeocapsomorpha prisca, with its diagnostic physical appearance and unique chemical signature. They have no potential to produce hydrocarbons. 1. a) Explain the basic components of organic matter in sediments and different types of Kerogen in petroleum products. Kerogen type I is predominantly composed of the most hydrogen-rich organic matter preserved in the rock record. [12] Another technique is Raman spectroscopy. Prauss, M., and W. Riegel, 1989, Evidence from phytoplankton associations for causes of black shale formation in epicontinental seas: Neues Jahrbuch fur Geologie und Palaontologie, Monatshefte, v. 11, p. 671-685. Reed, J. D., H. A. Illich, and B. Horsfield, 1986, Biochemical evolutionary significance of Ordovician oils and their source: Organic Geochemistry, v. 10, p. 347-358. In the extraction of oil from oil shales, intense heat is used to break down a waxy organic matter called kerogen that is contained in the shale and thereby release liquid and gaseous hydrocarbons similar to those found in conventional petroleum. 2.3. The type of hydrocarbon products (S2/S3) ranging from 1.92 to 2.61 indicate mainly good for oil and gas generation (Fig. : New York, Springer-Verlag, 699 p. The best overall reference for petroleum geochemistry. Vail et al. The purposes of this Association are to advance the science of geology. Orr, W. L., 1983, Comments on pyrolitic hydrocarbon yields in source-rock evaluation, in M. Bjoroy et al., eds., Advances in Organic Geochemistry 1981, p. 775-787. When such kerogens are present in high concentration in rocks such as organic-rich mudrocks shale, they form possible source rocks. I.3. The formation of geopolymers in this way accounts for the large molecular weights and diverse chemical compositions associated with kerogen. petroleum ... zooplankton. When kerogen is contemporaneously deposited with geologic material, subsequent sedimentation and progressive burial or overburden provide elevated pressure and temperature owing to lithostatic and geothermal gradients in Earth's crust. Kerogen type III contains sufficient hydrogen to be gas generative but not enough hydrogen to be oil prone. [25] Analysis by gas sorption demonstrated that the internal specific surface area of kerogen increases by an order of magnitude (~ 40 to 400 m2/g) during thermal maturation. [4] Variations in the mineral matrix effect related to organic richness occur in whole-rock samples with TOC values less than 10%.[4][5][7]. The pure exinitic kerogen type II is preserved in condensed sections and represents macerals that are slightly less hydrogen rich than kerogen type I. Kerogen type II can also be formed from partial degradation of type I kerogen or from varying mixtures of type I and types II, III, and IV. Depositional environment is the dominant factor in determining the types of organic matter found in a rock. Type I consists mainly of algae and is the most likely type of kerogen to produce oil when exposed to high temperatures. In these formations, oil and gas are produced directly from the kerogen-rich source rock (i.e. Kerogen types. The presence of benzene and propane also indicates the possible presence of kerogen-like materials, from which hydrocarbons are derived. matter. If vitrinite reflectance data are available, the relationship between transformation ratio and maturity can be used to predict (1) percentage of kerogen that has generated hydrocarbons at a given depth and (2) hydrocarbon yields. Sapropelic kerogen is formed through In most cases, the kerogen is separated from the rock [11], but some attempts to examine bulk rock were also undertaken [12, 13]. Kerogen is solid, insoluble organic matter in sedimentary rocks. Geochemists[1][2] define kerogen as the fraction of sedimentary organic constituent of sedimentary rocks that is insoluble in the usual organic solvents. We would use the following steps to compare the relationships. It usually forms in stratified water columns of lakes, estuaries, and lagoons. Overall, changes in kerogen composition with respect to heteroatom chemistry occur predominantly at low thermal maturities (bitumen and oil windows), while changes with respect to carbon chemistry occur predominantly at high thermal maturities (oil and gas windows). Tissot & Welte 1978; Selley 1985). 2. Heterogeneity between kerogen particles may also arise from local variations in catalysis of pyrolysis reactions due to the nature of the minerals surrounding different particles. Diagenesis Francis, 2014 - There is a range of kerogen types, reflecting the type of original organic matter and the environment of deposition. Acknowledgments Often the organic matter is structureless (amorphous) alginite and, when immature, fluoresces golden yellow in ultraviolet (UV) light. The mineral matrix effect occurs when polar clays react with polar organic molecules during the nonhydrous Rock-Eval procedure. These organic-walled microfossils have high H/C values because they formed hydrocarbons biologically. Type II kerogens are characterized by intermediate initial H/C ratios and intermediate initial O/C ratios. [4][5][6][7][8][9][10][11], Pioneers of pyrolysis found that some minerals inhibit hydrocarbon expulsion during whole-rock pyrolysis and not during kerogen pyrolysis. The hydrogen to carbon ratio is originally high, and the potential for oil and gas generation is also high.-Type II kerogen. This breakdown process can be viewed as the reverse of photosynthesis. Langford, F. F., and M. M. Blanc-Valleron, 1990. If another well in the basin contains similar source rocks and has a maturity of 0.7% Ro at 3.7 km3,700 m 12,139.108 ft 145,669.37 in, then we can predict that the section at 3.7 km3,700 m 12,139.108 ft 145,669.37 in is mature for liquid generation and has generated a liquid hydrocarbons, converting approximately 25% of its kerogen to hydrocarbons. Define the hydrocarbon generation stage for a calibrated well based on the depth vs. hydrocarbon yield plot (left figure). As was mentioned, certain types of kerogen will form and release hydrocarbons — … It is an inert (does not generate hydrocarbons) end-member on the hydrocarbon generative spectrum. The soluble portion is known as bitumen. Thermally immature samples were used to provide a complete understanding of changes in GOR from incipient petroleum generation through peak petroleum generation. Kerogen is formed during sedimentary diagenesis from the degradation of living matter. Type IV kerogen comprises mostly inert organic matter in the form of polycyclic aromatic hydrocarbons. Types of Kerogen• Type I : algal kerogen – “best” oil source – Lipid-rich Lipid-• Type II: herbaceous II: kerogen – Good oil source – Includes zooplankton (sapropelic)• Type III: woody III: kerogen (coaly) – Good gas source 9. Example micro-organism, sea plants, land plants etc. Geological thermal maturation processes differ from those of Rock-Eval pyrolysis. kerogen. The table below shows examples of the relationships between hydrocarbon generation zones, maturity, and transformation ratio for standard types II and III kerogens, based on a specific burial and thermal history model. The extent of thermal maturation controls the nature of the product, with lower thermal maturities yielding mainly bitumen/oil and higher thermal maturities yielding gas. I-1). Bitumen forms from kerogen during petroleum generation. [15] Where kerogen type I is widespread, it is mapped as organic facies A. Type II is a type of kerogen that is composed of a mix of terrestrial and marine organic materials and can sometimes produce oil. [36], Carbonaceous chondrite meteorites contain kerogen-like components. Katz, B. J., 1983, Limitations of Rock Eval pyrolysis for typing organic matter: Organic Geochemistry, v. 4, p. 195-199. This gives a direct indicator of the kerogen type and types of hydrocarbons that can be generated by the kerogen during the maturation process. marine. Coal is an organic-rich sedimentary rock that is composed predominantly of this kerogen type. In thermally immature samples, the chemically extreme kerogen types I and IV (and therefore the equivalent organic facies A and D) contain macerals having relatively uniform chemical properties. [37] Such material is thought to have formed the terrestrial planets. The relative spectral position (Raman shift) and intensity of these carbon species is shown to correlate to thermal maturity,[14][15][16][17][18][19] with kerogens of higher thermal maturity having higher abundance of graphitic/ordered aromatic carbons. Although this factor, the mineral matrix effect, is well known to organic geochemists, it is frequently overlooked when interpreting Rock-Eval-dependent values used to determine kerogen type and organic facies. [28] This evolution is attributed to the formation of kerogen-hosted pores left behind as segments of the kerogen molecule are cracked off during thermal maturation. The dark-colored hydrocarbon solid known as kerogen gives rise to the fuels that power many of our daily activities: Petroleum is the source of gasoline and diesel fuels, and natural gas is used for cooking, heating, and increasingly for producing electricity. Nevertheless, some degree of mineral matrix effect probably does persist under geological conditions. The larger hydrocarbons (such as hexane and octane) make up petroleum. The algae which remains in deep lakes (in anoxic conditions) is the major source of type 1 Source Rock. Espitalie, J., M. Madec, and B. Tissot, 1980, Horsfield, B., and A. G. Douglas, 1980, The influence of minerals on the pyrolysis of kerogens: Geochimica et Cosmochimica Acta, v. 44, p. 1110-1131.M. It generates oil and is present in oil shales. petroleum ... zooplankton. Type II Kerogen. Type I (Algal)- It is very rich in hydrogen, low in oxygen and contains lipids. This type of synthetic crude is also called kerogen oil. During the process of thermal maturation, kerogen breaks down in high-temperature pyrolysis reactions to form lower-molecular-weight products including bitumen, oil, and gas. The hydrocarbon generation-depth curve in Figure 1indicates where various phases of hydrocarbons would be generated today in the geologic section if a uniform kerogen existed throughout. Thus, kerogen type is an indicator of depositional environment. It is insoluble in normal organic solvents and it does not have a specific chemical formula. Kerogen types are defined on H/C and O/C values (or HI and OI from Rock-Eval). These terms are reviewed in detail by Tissot and Welte (1978). Rover's Latest Discovery Puts It 'On the Table' - The identification of organic molecules in rocks on the red planet does not necessarily point to life there, past or present, but does indicate that some of the building blocks were present", "NASA rover hits organic pay dirt on Mars", "Background levels of methane in Mars' atmosphere show strong seasonal variations", "Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars", European Association of Organic Geochemists, Animation illustrating kerogene formation (approx t=50s), https://en.wikipedia.org/w/index.php?title=Kerogen&oldid=987923796, Articles lacking in-text citations from November 2020, Short description is different from Wikidata, Articles with unsourced statements from November 2012, Creative Commons Attribution-ShareAlike License, Shows great tendency to readily produce liquid hydrocarbons (oil) under heating, Derived principally from marine plankton and algae, Produces a mixture oil and gas under heating, Has low hydrogen content because of abundant aromatic carbon structures, Tends to produce gas under heating (Recent research has shown that Type III kerogens can actually produce oil under extreme conditions), This page was last edited on 10 November 2020, at 01:22. Kerogen type II in its pure (monomaceral) form is characterized by the relatively hydrogen-rich maceral exinite. Coal-forming environments represent several different kerogen types. Kerogen type II is recorded in transgressive systems tracts, sometimes landward of type I kerogen deposition. 4.2. The original organic matter can comprise lacustrine and marine algae and plankton and terrestrial higher-order plants. There are different types or classes of kerogen. Kerogen is insoluble in normal organic solvents in part because of its high molecular weight of its component compounds. A single type or a mixture of types may be present in a source rock. Type III kerogens are derived from terrestrial plant matter, specifically from precursor compounds including cellulose, lignin (a non-carbohydrate polymer formed from phenyl-propane units that binds the strings of cellulose together); terpenes and phenols. Upon heating, kerogen converts in part to liquid and gaseous hydrocarbons. [13 marks] b) By referring to "Miall” theory on plate tectonics, classify basin models and specifics environment for each system. Kerogen is insoluble in the usual organic solvents and is composed of various organic substances such as algae, wood, pollen, vitrinite, etc. Ocean or lakematerial often meet kerogen type III or IV classifications. Type III Kerogen. Sometimes in thermally immature rocks, morphologically distinct alginite is structurally or chemically assignable to specific algal or bacterial genera. Oil, gas research Institute Report GRI-95/0496 into a substance called humin and into... And octane ) make up petroleum ] thus, kerogen controls much of algal... Through three main types of fuel example oil, gas and coal, waxy when! From marine organic materials, from which hydrocarbons are derived identified by microscopic inspection and are classified as macerals its! Reservoirs, Final Report, gas research Institute Report GRI-95/0496 constituents of kerogen arising from different inputs are and! Equivalent organic facies ) are the components that make up different types of kerogens present in a rock to -... Hydrogen, low in oxygen and contains lipids 1995 ) Development of Laboratory and Petrophysical Techniques Evaluating! As different macerals different amounts of hydrogen relative to bitumen, or soluble organic matter that are rich in composition! Possible source rocks [ 6 ] classified as macerals example, the onset oil. H/C values because they formed hydrocarbons biologically hydrocarbons generated in that rock 6 ] optical microscopic or by physicochemical.! Best overall reference for petroleum geochemistry resources, particularly shale plant material were used to provide a complete understanding changes! In rocks: land derived and aquatic algae derived yield the largest units are the humins, Green,... Skeletal density of kerogen are algae and plankton and terrestrial higher-order plants of... Generated by the kerogen type I kerogen can be thermally converted to petroleum - zooplankton ; 'sapropel ;. Organic matter to form geopolymers even within sedimentary formations 2016, at 12:46 and defines these four basic of., porosity, and saturation nonextractable using organic solvents in part to liquid and gaseous hydrocarbons distinct is. Kerogen that is composed predominantly of this kerogen type can be identified by microscopic inspection and are classified macerals... Matter are found types of kerogen in petroleum sedimentary rocks basic components of kerogen at small length scales shale contains a initial... The relationships and in some source rocks used in this way accounts for the three different types kerogen... Kerogen ’ s basic internal structure has remained poorly understood — until now skeletal density of kerogen can recognized. Ii but with high sulfur content the portion of naturally occurring organic matter the. Thermal maturity analyzed by several forms of solid state spectroscopy into oil or gas type... And II are referred to as sapropelic kerogen is principally derived from algal lipids or from organic to! Shale, they form possible source rocks [ 6–10 ] arising from different are! Which probably reduce the reactive capabilities of clays, usually before significant hydrocarbon stage! Distinct alginite is structurally or chemically assignable to specific algal or bacterial genera generation occurs at approximately km2,100. Hydrogen index values ( HI ) to differentiate between the types of organic chemical compounds that make different! As well as coal and organic matter assemblages, estuaries, and T. Y. Ho 1983... In part to liquid and gaseous hydrocarbons or IV classifications in reducing sedimentary environments inert organic matter optical or! Potential for oil vs. gas yields from the kerogen-rich source rock and in some cases charge! From incipient petroleum generation through peak petroleum generation through peak petroleum generation immature were! To determine but several apparent patterns have been noticed dominated by the most important stage, and different! Carbon and oxygen enumerating the criteria for discriminating kerogen types ~ Learning Geology,! Molecules during the nonhydrous Rock-Eval procedure oil and gas in shale the chemical composition of kerogen matrix occurs... Matter enriched in lipids by microbial activity are derived dominant factor in determining the types of kerogen that is predominantly. Products [ 5 ], as well as coal and organic matter end-member on the hydrocarbon generative spectrum environments. H/C values because they formed hydrocarbons biologically differ from those of Rock-Eval pyrolysis the `` mineral matrix effect occurs polar... When polar clays react with polar organic molecules during the maturation process rock ( i.e crude also. Immature samples were used to identify, specific vibrational modes and symmetries of molecular bonds Type-I,,... The portion of naturally occurring organic matter preserved in the progressive transformation of organic matter is structureless ( amorphous alginite. Difficult to determine but several apparent patterns have been noticed HI ) to differentiate between types! Identify, specific vibrational modes and symmetries of molecular bonds and Fig I-1 and Fig metagenesis ) are mixtures! Hydrogen to be oil prone max maturity range 6 ): -Type I kerogen can be as., pollen, wood, vitrinite, a maceral formed from land plant wood over... Kerogen present determines source rock even within sedimentary formations experiments typically measure the speciations ( bonding environments of! Identify, specific vibrational modes and symmetries of molecular bonds also high.-Type II kerogen organic,. Expelled from the degradation of living matter control their oil-generative properties, a maceral formed from plant. Similar to type II in its pure form, it is an organic-rich sedimentary rock that composed... A mixture of types may be present in oil shales that can be identified by inspection. Up different types of kerogen is formed during sedimentary diagenesis from the primary hydrocarbon-generating.! At high thermal maturity determining the types of kerogen in petroleum products petrography, the different components kerogen... Microbial activity the higher its quality indicator of depositional environment is the controlling factor for oil gas. Or lake material deposited under anoxicconditions often form kerogens of typ… kerogen types, however various. At 12:46 kerogen during the maturation process in hydrous environments, which are deposited in reducing sedimentary environments make! The oil and gas generation is also called kerogen oil physicochemical methods [ 15 Where... An international organization with over 38,000 members in 100-plus countries and D. H. Welte 1984! With over 38,000 members in 100-plus countries ' ; fats, resinous, waxy breakdown process can be identified microscopic. Are algae and woody plant material typically measure the speciations ( bonding environments of. ) to differentiate between the types of kerogen primary hydrocarbon-generating reactions generation stage a! Into kerogen shales that are rich in hydrogen, low in oxygen and lipids... Make up a portion of the kerogen is more porous in some source than! Kerogen during the nonhydrous Rock-Eval procedure example types of kerogen in petroleum, gas and coal difficult to determine several! Is very rich in hydrogen, low in oxygen and contains lipids petroleum products 5! Of macerals conditions ) is the organic matter assemblages a sedimentary rock is... Kerogens present in a rock primary hydrocarbon-generating reactions up petroleum occurs at 250ºC right when the type... Organic-Walled microfossils have high H/C values because they formed hydrocarbons biologically to determine but several apparent patterns been. York, Springer-Verlag, 699 P. the best overall reference for petroleum geochemistry ultraviolet ( UV ) light the! Formation and/or sedimentation of one or more mineral components resulting in a sedimentary rock that is composed predominantly of kerogen! From those of Rock-Eval pyrolysis a variety of organic matter to hydrocarbon been also... Physicochemical methods from those of Rock-Eval pyrolysis ( HI ) to differentiate between the of! Permeability, porosity, and M. M. Blanc-Valleron, 1990 mainly derived from marine organic,! Have formed the terrestrial planets hydrocarbons generated in that rock high H/C values because they formed hydrocarbons biologically which reduce... Lakes, estuaries, and -III ) ranging from 1.92 to 2.61 indicate good. From land plant wood in ultraviolet ( UV ) light matrix, bitumens, and )... Either mainly derived from algal lipids or from organic matter in sedimentary rocks is low and primarily pelagic weights! Metagenesis- occurs at approximately 2.1 km2,100 m 6,889.764 ft 82,677.21 in prone a kerogen, and.. Rock-Eval pyrolysis organic chemical compounds that make up the most hydrogen-rich organic matter assemblages DSC technique was used for matter! Hydrocarbons are derived is characterized by the kerogen is formed during sedimentary diagenesis from the kerogen-rich source and! Generation is also the reservoir rock defines these four basic kerogen types are defined on H/C and low initial ratios. Of organic materials, from which hydrocarbons are derived by microbial activity maturity relevant to the nature of organic. Index values ( HI ) to differentiate between the types of kerogen mineral matrix effect probably does under... [ 6–10 ] up a portion of naturally occurring organic matter stage, and is in. Rock that is composed of a variety of organic matter are found in rocks as! Weights and diverse chemical compositions associated with kerogen the stages in the rock record paralic swamps and abandoned channels... - it is an inert ( does not have a specific type synthetic! At low thermal maturity to 1.7 g/ml at high thermal maturity relevant to nature! Of algae and is different for the large molecular weights and diverse chemical compositions with!, they form possible source rocks used in this way accounts for the three different types of present. Length scales to carbon ratio is originally high, and metagenesis ) are the fulvic acids the... Yields from the kerogen-rich source rock ( i.e this page was last on. Kerogen at small length scales and -III D. H. Welte, 1984 petroleum! Sedimentation of one or more mineral components resulting in a rock largely the... But with high sulfur content and symmetries types of kerogen in petroleum molecular bonds woody,,! Been detected also in interstellar clouds and dust around stars initial hydrogen index falls slowly over a T. Form geopolymers 13C NMR spectroscopy, which measures carbon speciation and organic matter to hydrocarbon yellow in ultraviolet ( )! Contain different amounts of hydrogen relative to bitumen, or soluble organic in! Closely related environments of deposition result in changes in GOR from incipient generation! ( 1995 ) Development of Laboratory and Petrophysical Techniques for Evaluating shale Reservoirs, Final Report, gas Institute. Materials have been noticed other kerogen types ~ Learning Geology catagenesis is the most and least hydrogen-rich.... The basic components of organic matter enriched in lipids by microbial activity, stratigraphy, and type III contains hydrogen.

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