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Catagenesis (geology)
Catagenesis is a term used in petroleum geology to describe the cracking process which results in the conversion of organic kerogens into hydrocarbons. Theoretical reaction Catagenesis is the second stage of maturation of organic carbon on the path to becoming graphitic. This geologic process accounts for very significant changes in the biogenic materials that make up the carbonaceous sediment. During catagenesis, the temperature increases, the pressure increases, and both organic and inorganic constituents “adjust” their phase or form to compensate. The process of “lithification” begins during this stage. Generally speaking, a rise in temperature results in the volatization of unstable species or elements that are weakly attached to carbon atoms. Increased temperature and pressure also result in the cessation of biogenic processes. One way to express these changes is to look at the ratio of oxygen to carbon, or hydrogen to carbon as the sediment matures. In almost all ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petroleum Geology
Petroleum geology is the study of origin, occurrence, movement, accumulation, and exploration of hydrocarbon fuels. It refers to the specific set of geological disciplines that are applied to the search for hydrocarbons (oil exploration). Sedimentary basin analysis Petroleum geology is principally concerned with the evaluation of seven key elements in sedimentary basins: * Source * Reservoir * Seal * Trap * Timing * Maturation * Migration In general, all these elements must be assessed via a limited 'window' into the subsurface world, provided by one (or possibly more) exploration wells. These wells present only a 1-dimensional segment through the Earth, and the skill of inferring 3-dimensional characteristics from them is one of the most fundamental in petroleum geology. Recently, the availability of inexpensive, high quality 3D seismic data (from reflection seismology) and data from various electromagnetic geophysical techniques (such as magnetotellurics) has greatly aide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction Rate Constant
In chemical kinetics a reaction rate constant or reaction rate coefficient, ''k'', quantifies the rate and direction of a chemical reaction. For a reaction between reactants A and B to form product C the reaction rate is often found to have the form: r = k(T) mathrmm mathrm Here ''k''(''T'') is the reaction rate constant that depends on temperature, and and are the molar concentrations of substances A and B in moles per unit volume of solution, assuming the reaction is taking place throughout the volume of the solution. (For a reaction taking place at a boundary, one would use moles of A or B per unit area instead.) The exponents ''m'' and ''n'' are called partial orders of reaction and are ''not'' generally equal to the stoichiometric coefficients ''a'' and ''b''. Instead they depend on the reaction mechanism and can be determined experimentally. Elementary steps For an elementary step, there ''is'' a relationship between stoichiometry and rate law, as determined by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphic Reaction
A metamorphic reaction is a chemical reaction that takes place during the geological process of metamorphism wherein one assemblage of minerals is transformed into a second assemblage which is stable under the new temperature/pressure conditions resulting in the final stable state of the observed metamorphic rock. Examples include the production of talc under varied metamorphic conditions: :'' serpentine + carbon dioxide → talc + magnesite + water'' :''chlorite + quartz → kyanite + talc + water'' Polymorphic Transformations Exsolution Reactions Devolatilization Reactions Continuous Reactions Ion Exchange Reactions Oxidation/Reduction Reactions Reactions Involving Dissolved Species Chemographics Petrogenetic Grids Schreinemakers Method Reaction Mechanisms See also * Index mineral An index mineral is used in geology to determine the degree of metamorphism a rock has experienced. Depending on the original composition of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Fuel
A fossil fuel is a hydrocarbon-containing material formed naturally in the Earth's crust from the remains of dead plants and animals that is extracted and burned as a fuel. The main fossil fuels are coal, oil, and natural gas. Fossil fuels may be burned to provide heat for use directly (such as for cooking or heating), to power engines (such as internal combustion engines in motor vehicles), or to generate electricity. Some fossil fuels are refined into derivatives such as kerosene, gasoline and propane before burning. The origin of fossil fuels is the anaerobic decomposition of buried dead organisms, containing organic molecules created by photosynthesis. The conversion from these materials to high-carbon fossil fuels typically require a geological process of millions of years. In 2019, 84% of primary energy consumption in the world and 64% of its electricity was from fossil fuels. The large-scale burning of fossil fuels causes serious environmental damage. Over 80% of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagenesis
Diagenesis () is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust. In the early stages, the transformation of poorly consolidated sediments into sedimentary rock (lithification) is simply accompanied by a reduction in porosity and water expulsion (clay sediments), while their main mineralogical assemblages remain unaltered. As the rock is carried deeper by further deposition above, its organic content is progressively transformed into kerogens and bitumens. The process of diagenesis excludes surface alteration (weathering) and deep metamorphism. There is no sharp boundary between diagenesis and metamorphism, but the latter occurs at higher temperatures and pressures. Hydrothermal solutions, meteoric groundwater, rock porosity, permeability, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
