Visual kerogen types and quality are shown in the table below. Pdf the use of the term kerogen, originally described as the organic matter in oil. Until recently, the composite has been commonly thought to have been produced in the early solar nebula by a fischertropschtype process, involving the catalytic synthesis of hydrocarbons from carbon. The thermal alteration of kerogen and the formation of oil. Significant experimental effort in the study of shales and kerogen has produced a broad diversity of experimentally determined structural and thermodynamic properties even for samples. Kerogen is solid, insoluble organic matter in sedimentary rocks. Pdf kerogen type and its distribution map of the lower. Coalforming environments represent several different kerogen types. Kerogen consists mainly of paraffin hydrocarbons, though the solid mixture also incorporates nitrogen and sulfur. Typical organic constituents of kerogen are algae and woody plant material. As marine life died, it settled at the sea bottom and became buried in layers of clay, silt. Upon heating, kerogen converts in part to liquid and gaseous. Kerogen from the cambrian deposits of the kuonamka formation. Structure of kerogen revealed mit energy initiative.
It is very important in the formation of hydrocarbons because it. The term kerogen will be used here to designate the organic constituent of the sedimentary rocks that is neither soluble in aqueous alkaline solvents nor in the common organic solvents. The carbon in ancient carbonaceous chondritic meteorites is mainly in a hydrocarbon composite similar to terrestrial kerogen, a crosslinked structure of aliphatic and aromatic hydrocarbons. The classification of kerogen type, pematang brown shale formation, is classified into kerogen type iii, which is shown in figure 3b and c. Types i and ii are referred to as sapropelic kerogen, and type iii is known as humic kerogen. Bitumen forms from kerogen during petroleum generation. Roberts abstract burial history, thermal maturity, and timing of hydrocarbon generation have been modeled for four petroleum sourcerock horizons throughout the uintapiceance province.
Kerogen is primary form of organic matter representing solid depositional particles similar to framework mineral grains figure 6. The kerogen shrinks as its mass is converted to petroleum and its hydrogen content decreases. Oil shale formation takes place in a number of depositional settings and has considerable compositional variation. It is not soluble to normal petroleum solvents, like carbon disulfide. And yet, kerogens basic internal structure has remained poorly understood until now. It is insoluble in normal organic solvents because of the high molecular. Based on the original kerogen type and toco, the gasgeneration and storage potentials of the evie, middle otter park, and muskwa members are higher than those of other members. Jun 03, 2015 what kerogen is defined by solubility. The thermal maturity of the known ostrava formation ranges from 0.
Kerogen, bitumen and oil all appear dark grey in standard grayscale backscatter electron bse sem images. Thermal maturity and oil and gas generation history of petroleum systems in the uintapiceance province, utah and colorado by vito f. Parameters such as total organic carbon toc, kerogen type, and. Formation evaluation of an unconventional shale reservoir.
For kerogen to form, dead phytoplankon, zooplankton, algae, and bacteria must sink to the bottom of an ancient still water environment. Petroleum formation petroleum forms by the breaking down of large molecules of fats, oils and waxes that contributed to the formation of kerogen see chapter 6. The formation of petroleum penn state college of earth and. Kerogen is a prime constituent of shale formations and plays a crucial role in shale gas technology. There is a growing need to identify organic content in terms of quantity total organic carbon toc and quality kerogen type, thermal maturity in promising shale formations through indirect seismic data, which is. Petroleum is the source of gasoline and diesel fuels, and natural gas is used for cooking, heating, and increasingly for producing electricity.
Estimation of original kerogen type and hydrogen index using. Accurate element concentrations and standalone determination of total organic carbon toc by litho scanner highdefinition spectroscopy service in a shale gas reservoir are used by a canadian operator to correct matrix density and porosity and determine kerogen volume and reservoir quality. Pdf kerogen and palynomorph analyses of the midcretaceous. The sourcerock potential is excellent for the evie member with an approximately 75% difference between toco and measured presentday toc. A study based on geochemical and paleogeography data has been conducted to generate kerogen type and its distribution for lower baong formation. Kerogen is insoluble in water and in organic solvents such as benzene or alcohol. Kerogen composition is also affected by thermal maturation processes. The addition of greater heat is necessary to convert kerogen to liquid or gaseous hydrocarbons and the process takes time. Consisting of an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter by 10,000 fold. Kerogen slides were made from 92 core samples selected from the upper triassic mungaroo formation in four wells in the gorgon area of the northern carnarvon basin. Unconventional resources of shale hydrocarbon in sumatra. In this breakdown process, which is basically the reverse of photosynthesis 4, large biopolymers from proteins and carbohydrates begin to partially or completely dismantle. It is insoluble in normal organic solvents and it does not have a specific chemical formula. Kerogen and palynomorph analyses of the midcretaceous bahariya formation and abu roash g member, north western desert, egypt.
Kerogen associations and paleoenvironmental interpretation. When organic aquatic sediments proteins, lipids, carbohydrates are deposited, they are very saturated with water and rich in minerals. Abstractkerogens isolated from four rocks of ordovician age from north america have been. The present invention is directed to methods for extracting a kerogenbased product from subsurface oil shale formations, wherein such methods rely on fracturing andor rubblizing portions of said formations so as to enhance their fluid permeability, and wherein such methods further rely on chemically modifying the shalebound kerogen so as to render it mobile. Kerogen is immobile but can be thermally cracked, and. Kerogen characterisation and petroleum potential of the late. The subsequent and last stage of the evolution of organic matter in sedimentary basins at. This process began millions of years ago, when small marine organisms abounded in the seas.
However, the grain density determined from the elements does not account for kerogen in the rock, which makes. For example, a visual estimate of kerogen type might be stated as 50% woody, 45% amorphous, 5% inertinite. Monterey kerogen commonly contains abundant chemically bound sulfur 814 wt. A new analysis, by a joint team of researchers at mit, the french government research organization cnrs, and elsewhere, has revealed kerogens internal structure, in detail down to the atomic level. Kerogen is formed during sedimentary diagenesis from the degradation of living matter.
Oct 09, 2015 kerogen is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. Most samples comprised 90% amorphous organic matter aom. Us7500517b2 kerogen extraction from subterranean oil shale. The slides were examined to investigate relationships between kerogen assemblages and their depositional environments depofacies.
Kerogen origin, evolution and structure request pdf researchgate. Organic matter insoluble in organic solvents because of the large molecular weight up to several thousand daltons defined by petroleum. Kerogen is insoluble in the usual organic solvents and is composed of various organic substances such as algae, wood, pollen, vitrinite, etc. In general, the more amorphous kerogen present, the more oil prone the rock is. This study confirmed that a potential for gas generation exist in this basin. Shale gas is an unconventional source of energy, which has attracted a lot of attention during the last years. In petroleum studies the kerogen are classified into three basic types i, ii, and iii based on the ratio between their c, h, and o content, e. Sapropelic kerogen is formed through decomposition and polymerization products of fatty, lipid organic material, such as algae and spores, and is. Diagenesis is a process of compaction under mild conditions of temperature and pressure. Accurate porosity and kerogen volume for shale gas reservoir. The formation of kerogen represents a major step in the formation of oil and natural gas, as kerogen serves as the source of these fossil fuels. As with other intermediate kerogen types, however, various maceral mixtures or degradational processes can contribute to kerogen type iii formation. Kerogen density revisited lessons from the duvernay shale.
An evaluation of the resource potential of the tyler. Kerogen is a complex mixture of organic chemical compounds that make up the most abundant fraction of organic matter in sedimentary rocks. An accurate matrix density is required to compute the correct porosity from a bulk density measurement. Geochemical and biostratigraphy data from eight pt. In terms of organic richness, this formation is indicated by organic richness varying from 0. Fika formation, late cretaceous, kerogen, palynofacies, aromatic. Kerogen types and maturity levels play an important role in determining the characteristics of the products that will be generated from a specific kerogen tissot et al. This initial petroleum, often called imma ture oil or bitumen as it is dominated by complex.
Petroleum formation the chemistry of petroleum formation. Where kerogen forms part of the framework supporting overburden stress, the source rock consolidates as fast as the kerogen shrinks compaction equilibrium. The source rock thins during transformation, but generation creates negligible porosity in kerogen. The formation of petroleum penn state college of earth. Origin of hydrocarbons formation process from planktonic remains to kerogen. Kerogen associations and paleoenvironmental interpretation of. As kerogen is a mixture of organic materials, it is not defined by a single chemical formula. At the demise of living matter, such as diatoms, planktons, spores and pollens, the organic matter begins to undergo decomposition or degradation. Request pdf kerogen from the cambrian deposits of the kuonamka formation northeastern siberian platform kerogens from the lower and middle cambrian deposits of the kuonamka formation in the. Characteristics and elemental composition of oil shale and kerogen, %. Kerogen, complex waxy mixture of hydrocarbon compounds that is the primary organic component of oil shale.
Pdf chemical and petrographic classification of kerogenmacerals. For example, kerogen from the green river formation oil shale deposit of western north america contains. Maturity of kerogen, petroleum generation and the application. In summary, kerogen is a key intermediate in the formation of oil and gas. Oil ratios for source rocks containing typei, ii, iis. Yaser abdullah abdullah almashramah maturity of kerogen. This means that pematang brown shale formation has the. The tyler formation lower pennsylvanian is a regionally extensive, organic rich unit that contains, over a significant part of its range, good to excellent quantities of kerogen. It is very important in the formation of hydrocarbons because it is what generates oil and gas. Petroleum expulsion and formation of porosity in kerogen. Upon heating under pressure, however, the large paraffin molecules break down into recoverable gaseous and liquid substances resembling petroleum.
This is the most frequent acceptance of the term kerogen, and results from a direct generalization to other rock types of the definition by breger 1961 in carbonaceous shales and oil shales. Changes in type ii kerogen density as a function of maturity. Oil shale geology is a branch of geologic sciences which studies the formation and composition of oil shalesfinegrained sedimentary rocks containing significant amounts of kerogen, and belonging to the group of sapropel fuels. Kerogen kerogen is a finegrained, amorphous organic matter. Prior to and during the early phase of petroleum generation, kerogen densities range between 1. Burdelnaya russian geology and geophysics 50 2009 638643 2,2. We used the published ultrasonic and kerogen content information from vernik and nur 1994 for bakken shale. Kerogen is insoluble in water and in organic solvents such as benzene or. The formation of larger bitumen molecules suggests the hydrolytic enzyme biodegradation may be a similar process to an accelerated maturation of sedimentary. The darkcolored hydrocarbon solid known as kerogen gives rise to the fuels that power many of our daily activities. Different types of kerogen contain different amounts of hydrogen relative to oxygen and carbon and thus control the type of hydrocarbon that will be generated in the sedimentary rocks in due course of time. Thermal maturity and oil and gas generation history of. Although it is recognized that the original source of carbon and hydrogen was in the materials that made up primordial earth, it is generally accepted that these two elements had to pass through an organic phase to be combined into the varied complex molecules recognized as hydrocarbons. The original organic matter can comprise lacustrine and marine algae and plankton and terrestrial higherorder plants.
Kerogen is defined as the sedimentary organic matter generating petroleum, an insoluble product. Pspetroleum expulsion and formation of porosity in kerogen. Kerogens were purified from 26 samples of the kimmeridge clay formation over the full range of maturities pertinent to petroleum generation. In its pure form, it is composed of vitrinite, a maceral formed from land plant wood.
Its chemical compositioin is 75% c, 10% h, 15% other sulfur, oxygen, nitrogen, etc. A new mechanism for the formation of meteoritic kerogenlike. This paper documents the critical role of organic sulfur in the early formation of bitumen and oil from a sulfurrich kerogen from the miocene monterey formation in california. Organic matter capable of producing petroleum end result of diagenesis stage during the process of petroleum formation is conversion of organic matter to kerogen. Abstract the movement of petroleum from organicrich source beds to potential carrier beds is the net result of two processes.