Inorganic Origin of Petroleum
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INORGANIC ORIGIN OF PETROLEUM Abstract The concept of the organic origin of petroleum has been dominant for the last 70 years. Generation of petroleum hydrocarbons has been explained by transformation of dissipated organic matter in clay-carbonate sediments under the influence of temperature and pressure increase with depth, separation of the hydrocarbons freshly generated, and their migration into porous reservoir beds. According to the organicorigin-concept, the extremely low content of hydrocarbons in the rocks is unimportant, because the existence of a huge mass of “source” rocks for the petroleum generated salves the problems of petroleum-migration mechanism, petroleum accumulation, petroleum formation, and its spatial distribution. In the course of time this concept of the organic petroleum source rocks has become a dogma, and all questions of petroleum geology and exploration are approached from the assumption that the organic origin is proved. Many works are devoted to a thorough and detailed study of the various consequences of the origin concept. However, while the organic theory proliferated, the concept of the organic synthesis of hydrocarbons and plutonic origin of petroleum also grew. These concepts, associated mainly with the names of prominent scientists of the 19th century, were considered by the organic-theory protagonists to be obsolete. As a result they were shelved, as explained in detail by Hedberg and by Datt and Reynolds. However the stream of new information coming from new exploration areas and from new ideas in the fields of geology, geochemistry, geophysics, astrophysics, and so on has contributed to appearance of new knowledge which categorically rejects all aspects and consequences of the organic theory. The struggle between the opposing theories finally focused into broad discussions-including symposia accompanied and followed by many publications on the problem, especially in the socialist countries. Unfortunately all this is unknown to foreign petroleum geologists, as can be jusged by study of the works of Hedberg, Colombo, Levorsen, Datt and Reynolds, and others. The aim of the present survey is to bring to the attention of a wide circle of geologists the new ideas and a picture of the present state of the problem of petroleum formation from the viewpoint of inorganic-origin theory. Introduction During the whole long history of scientific publications on the nature of petroleum, two competing concepts about its origin have existed-organic and inorganic. Even during the last century, when science progress and deepdrilling data seemed to create a stable basis for well-founded judgments (and under the then prevailing opinion that petroleum is the product of transformation of vegetal-animal matter in the mineral state), there appeared theories treating petroleum as the product of inorganic synthesis taking place under very high temperature and pressure conditions. From the beginning of this century the organic theory has prevailed, and important works in this field by Powers (1932), Uspenskiy and Gorskaya (1938), Sokolov (1948), Hedberg (1964), Colombo (1967), Levorsen (1967), Dott an Reynolds (1969), and
others mentioned with profound respect the views of Berthelot (1866), Mendeleyev (1902), and Coste (1904, 1905), but as having been shelved long ago. Evidently because of the “language barrier,” a sizable group of USSR scientists‟ work was omitted in these surveys (the scientists of various specialties who have turned to the idea of natural inorganic synthesis of petroleum hydrocarbons). This has been a source of deep disappointment to me and to many of my colleagues who have spent many years in research and have published comprehensive results contrary to organic theory, because of new information on the geochemistry, geophysics, astrophysics, and geology of petroleum-bearing regions. New generalizations based on these new data and vociferous arguments against inorganic theory have been published, have caused protests, and have produced attempts to disprove the inorganic-origin arguments. Discussions have been published, but generally are known only to geologists who followed the programs and proceedings of the pertinent data from three sessions of the World Petroleum Congress. Each theory of the origin of petroleum results from questions directly relating not only to hydrocarbon formation, but also to migration processes and the entrapment of large accumulations. Organic and inorganic theories are absolute antagonists insofar as processes, factors, and phenomena involved in each theory are concerned. Critical and unbiased consideration of the arguments favoring the inorganic origin is of interest if only because it merits “equal time” for expressing the viewpoint of inorganic theory versus views of unquestioning and dogmatic supporters of the organic origin of oil. …. … THEORY OF INORGANIC ORIGIN OF PETROLEUM I wish to point out that the modern group of USSR geologist who advocate the inorganic origin of oil are fully aware that they must prove the concept both chemically and geologically. In practice, the arguments mustered against the organic theory deal only with the chemical aspects, as one sees clearly in Dott and Reynolds‟ (1969) recent book. Dott and Reynolds dealt with purely chemical hypotheses proposed by various chemists and some geologists for the last 150 years. Unfortunately they did not consider modern ideas of USSR geologists and geochemists, whose works on inorganic theory have been published during the last 25 years. Dott and Reynolds did not even mention the critical discussions at the Moscow meeting of 1958. Similar important meetings were held in L‟vov in 1954 and 1957, and the main papers of inorganic theory were published by Kudryavtsev (1955, 1959), Kropotkin and Shachvarstova (1959), Linetskiy (1960), and Grinberg (1966). In 1958 the third discussion meeting took place in Moscow. Its proceedings were published in 1959 in the collection “Problem of petroleum and gas origins and conditions of their formation”.
A fourth meeting took place in Moscow in 1968. The papers presented at this meeting were preprinted in 1967. The final results of the meeting were published in 1972 in “Origin of oil and gas deposits and conditions of their formation”. Moreover, during the last decade, several volumes of the Ukrainian Academy of Sciences were published to prove the organic origin of petroleum. Among those are “Theoretical problems of petroleum geology” (1962), “Problems of origin of oil” (1966), “Problem of origin of oil and gas and formation of commercial reserves” (1966), and “Problems of inorganic origin of oil” (1971). The language barrier has played a role. In the recent report by Hedberg (1964), we do not find reference to the books by Kudryavtsev (1959, 1963), the acknowledged leader of the modern USSR inorganists. Hedberg‟s report includes none of the many works on inorganic theory by geologists, geophysicists, and chemists from Leningrad, Ukraine, Volga-Urals, Siberia, etc. Following a presentation of basic facts, I shall review the chemical aspects of petroleum formation in the theory of the inorganic synthesis of petroleum hydrocarbons. This to me is very necessary, because supporters of inorganic theory are reproached constantly with the claim that, in their works, the chemical aspects of the problem are left undeveloped in contrast to the organic theory in which chemical aspects are developed quite extensively and completely, in the minds of some. Hedberg (1969) showed what this “completeness” costs–complete blindness to alternatives. As to the modern variants of inorganic theory, it should be noted that a selection of possible chemical schemes that are logical and natural from the point of view of chemistry and linked with the geologic requirements is sufficient for now. Inorganic theory is linked with the upper mantle, and such a linkage naturally is conditional because all geologic considerations concerning the upper mantle also are conditional. It is not possible to observe directly the chemical processes taking place at upper mantle depths. However, there is no doubt today as to the strong possibility of abiogenic synthesis of chemical reactions of petroleum hydrocarbons under thermodynamic conditions in the upper mantle zone. According to Kapchenko‟s (1963) survey, the original compounds for the formation of petroleum hydrocarbons can be CO2 and H2, CO and H2O, and H2O and CO2. Kapchenko stated “… during synthesis from CO2 and H2 and CO2 and H2O, methane, naphthene, and aromatic hydrocarbons can be obtained similar to those essentially comprising natural oil (the difference being only in some ratios among them).” Modern methods have made it possible to prove the reality of geochemical schemes meeting the required conditions for an abiogenic synthesis. These schemes by Kudryavtsev (1955), Kropotkin and Shakhvarstova (1959), Slenzak (1966), Levin (1969), Chekalyuk (1971), and others can be criticized from the geologic point of view; the future will show which ideas–organic or inorganic–are closer to the truth. Today only the geologic aspect of the problem is clear, and the geologic facts flatly contradict organic theory.
Commercial Petroleum Accumulations in Crystalline Rocks of Basement The most direct and most convincing proof of the inorganic theory is the existence of commercial petroleum accumulations in crystalline and metamorphic basement rocks. With prospecting of new regions and increasing drilling depths, the number of such accumulations is growing and it is impossible to ignore them without comment. Kudryavtsev (1959) considered the geologic meaning of oil and gas accumulations in crystalline and metamorphic basement rocks, ranging in some from insignificant accumulations to deposits of tens of millions tons (La Paz and Mara, Venezuela; Kansas and adjacent Mid-Continent region; California) and in intrusions into sediments. Many such fields are the topics for very complete reports in the literature, reports which discuss the actual geologic setting with respect to the possible genetic link between petroleum formation and a nearby sedimentary complex or to petroleum inflow from deep zones where the possibility of biogenic formation is excluded. Kudryavtsev (1959) critically and thoroughly considered each case described in the literature published before 1959, and each of the examples which he studied is a powerful argument favoring the inorganic theory. It is logical to expect that there would be many critical comments directed at disproving the conclusions of Kudryavtsev‟s study. Even so Kudryavtsev‟s 1959 book was not mentioned by Hedberg (1964). However, Dott and Reynolds (1969) did note that “N. A. Kudryavtsev (1959), of the USSR, had cite a great many occurrences of oil or indications of it in igneous and metamorphic rocks as compelling evidence for an inorganic origin, but N. A. Eremenko disagreed: „Kudryavtsev strives to show that … the oil could not have entered from sedimentary deposits … (where sufficient data can be gathered) attests indisputably to their [the hydrocarbons] formation in connection with the sedimentary section, or admits of this possibility.‟ (Eremenko, 1961)” This brief remark on such a great work forces one to think that Dott and Reynolds became acquainted with Kudryavtsev book only by citation from N. A. Eremenko‟s work (1961). From Eremenko‟s work the reader can get the erroneous impression that a profound and complete analysis of the geologic conditions for the formation of petroleum and petroleum-bitumen deposits in crystalline and metamorphic rocks on all continents has been reviewed critically by Eremenko. The reader might conclude further that Eremenko has demonstrated the error of Kudryavtsev‟s interpretation. But that is not so. The sum total of the criticism leveled at Kudryavtsev boils down solely to the quote cited and to the assumption that, near each example analyzed by Kudryavtsev, sedimentary rocks are present from which petroleum could have migrated. On the basis of what we know of petroleum migration, genesis, etc., even today, such an argument is inadmissible. Oil and gas accumulations occur in crystalline and metamorphic basement rocks on nearly all continents; moreover, some are huge commercial deposits. …
Ideas of USSR Inorganic-Theory Advocates Summarizing his ideas about the formation of petroleum hydrocarbons, Kudryavtsev (1955) wrote: Hydrocarbons are formed from carbon and hydrogen which are present not only in stars and the sun but also in the earth magma, a fact which is confirmed by the presence of hydrocarbons and petroleum in lavas and volcanic gases as well as by dissipated carbon and graphite deposits in effusive rocks, diamonds in kimberlites, and hydrogen in dunites. Carbon and hydrogen together from under high temperature methine–CH so typical for incandescent stars and the sun with temperature of 6.000 – 12.000ºC, and methylene– CH2 characteristic for stars of lower temperature (3.000 – 4.000ºC). With a further temperature decrease, methyl is formed–CH3 and then methane. Certainly methine, methylene, and methane are present in the earth‟s interior. Carbon and hydrogen combine with each other irrespective of where they are–on the sun, the earth, or any celestial body. It is known that the hydrocarbons mentioned above do not exist at normal temperatures, a fact which demonstrates their great chemical activity and their affinity for other elements and compounds. Consequently with a temperature decrease, they combine both with each other (for example, methine in C2H2 – acetylene; in C6H6 – benzene in which acetylene is easily polymerized under high pressure; methylene in C6H12 and so on) and with hydrogen in varied ratios and with various molecular structure yielding different hydrocarbons leading with methane. ... ... Mendeleyev‟s (1902) theory for hydrocarbon formation thus has conserved its meaning; its basics aspects are considered in several modern works. Thus the geophysicist Elanskiy (1966) pointed out that the simplest reaction, 2FeC + 3H2O = Fe2O3 + C2H6 Possibly is only a partial solution of the inorganic petroleum origin problem proposed by Mendeleyev and that the formation of petroleum hydrocarbons can be associated with olivine serpentinization according to the following reaction (the Mendeleyev – Hess equation): 3(Fe,Mg)2SiO4 + 7H2O + SiO2 + 3CO2 = 2Mg3[OH]4Si2O3 + 3Fe2O3 + C2H6 + Q The left side of the equation contains olivine, water, silica, and carbon dioxide; the right side includes serpentine, hematite, and naphthene. The Mendeleyev – Hess equation permits the occurrence of hydrocarbons not only in a cooling gabbroid intrusion but also in geothermal solutions. According to Kapchenko (1963), “with cooling magma, the high-temperature front is moving to the center and both geothermal and hydrocarbon synthesis processes will develop in fractures of the upper part of magmatic rocks which already has recrystallized”
In the recent conferences held in the USSR, supporters of the inorganic theory were reproached with the fact that they relate the processes of the petroleum hydrocarbon formation “to a mysterious upper-mantle womb” as Uspensky (1970) put it, where thermodynamic conditions and physical-chemical processes only can be imagined. Using the deductive method based on classical thermodynamic principles and modern ideas of geology and geophysics, I conclude that, under high temperatures and pressures present within the “waveguide” or the so called low-velocity “Gutenberg layer” of the upper mantle in ultramafic rocks containing iron oxide and volatile components (H2O and CO2), mixtures of organic compounds equivalent to natural petroleum are formed which are able to exist there in thermodynamic equilibrium with the surrounding mantle medium. Thermodynamic analysis and geologic conclusions concerning the formations of hydrocarbons in the upper mantle-published by Chekalyuk-have met, as should be expected, sharp criticism from the chemists, and at the 1968 meeting, several paper were generated. ... CONCLUSION The material presented demonstrated that the organic theory of origin of petroleum does not correspond to the modern state of knowledge in the field of geology, geochemistry, geophysics, thermodynamics, and other sciences; in fact it is an outmoded, outdated concept. Instead, the general inorganic theory of petroleum meets the requirements of new knowledge completely. The combination of various factors involved in the natural process of petroleum formation leads to many problems of petroleum geology which require further investigation. But the main concepts of the new (or regenerated) inorganic theory can be formulated quite clearly. Petroleum hydrocarbons which constitute the substance called “natural petroleum” are one of the several natural fluid mixtures. Its components-petroleum, gas, and juvenile water former under the thermodynamic conditions of the upper mantle-ascended under great pressure along plutonic faults close to the earth‟s surface where, depending on pressure and temperature, the fluid mixture separated into independent phases. This scheme explains the regularity of patterns that are observed among petroleum and gas accumulations, as well as their spatial distribution associating them with the processes of our planet‟s development. The inorganic theory explains the richness of the continental shelves where large deep faults are predictable. It also explains the paradoxical salt domes in the Gulf of Mexico, the reported petroleum occurrences in the giant rift zone in the midocean ridge of the Atlantic Ocean, and the accumulations in the Tonga Archipelago in the Pacific Ocean.