How is oil formed

  Oil is the blood of contemporary industry, the cornerstone of social stability, and the lifeblood of national prosperity.
  The word “oil” comes from Shen Kuo’s “Mengxi Bi Tan”. The description of oil in the book is the first record of this substance in human history. Since the discovery of oil, humans have been using oil without interruption, and until today its application covers all aspects of our lives, ranging from aerospace and space to food, clothing, housing and transportation. It can be said that each of us cannot live without close contact with petroleum products every day. Since oil is so important and has such a close relationship with us, do we know our close partner? Where does oil come from? How long can it accompany us? Is it inexhaustible and inexhaustible?
  The author has consulted a large number of documents and found that petroleum is the world’s first energy factor in industry, but the source of it has been divergent. The whole can be summarized as two theories of “organic origin” and “inorganic origin”. The former believes that oil is formed by microorganisms in ancient oceans or lakes after a long evolution, which can be summarized as biological sedimentation to oil. This theory holds that oil has a long time of formation and cannot be repeated in human history, so oil is not renewable. Resource, this doctrine is the mainstream view in petroleum geology; the latter believes that petroleum is produced by the carbon element inside the earth’s crust through a variety of physical and chemical reactions under high temperature and high pressure conditions, and has nothing to do with biology. This view believes that oil is a renewable resource that is continuously formed in the earth’s crust at all times.
  The theory of organic genesis believes that petroleum is produced by organic matter, which mainly comes from four kinds of organisms in ancient times: bacteria, phytoplankton, zooplankton, and higher plants. After these creatures die, part of their bodies will be destroyed by oxidation and decomposition, but some will still be preserved in sediments such as sediment under suitable conditions. These sediments will be buried deeper and deeper with the passage of time. During the process of burial, these organic substances have undergone complex biochemical and chemical changes, and formed kerogen through the process of sapropionization and humification. With the further increase of the burial depth, under certain temperature and pressure conditions Kerogen gradually undergoes catalytic cracking and thermal cracking to form the original form of “raw oil”. Then these crude oils “slid out” from the rocks where they were generated, after the first migration, the second migration, and finally a large amount of accumulation in a suitable environment to form oil reservoirs, which are then discovered, exploited and utilized by us.
  The theory of petroleum organic genesis can also be subdivided into a number of different branch theories. At present, it is widely recognized and used to guide petroleum exploration work is the late oil generation theory of petroleum organic genesis proposed by some scholars such as PH Eberson in the United States-cheese Root oil theory, the theory believes that oil is insoluble organic matter in sedimentary rocks, which is generated through pyrolysis in the late diagenesis. The many foundations of the theory of organic oil generation can be summarized in the following three aspects:
  (1) Petroleum fractions are optically active. Biological organic matter generally has optical activity, while inorganic matter generally does not have optical activity.
  (2) The sediments contain various hydrocarbon compounds that constitute petroleum. There are many organic compounds with biogenic signs in petroleum, such as yelin, phytan and sterane.
  (3) The vast majority of 99% of the world’s oil and gas fields are located in sedimentary rock areas.
  The Russian chemist Mendeleev is considered to be the proponent of the theory of inorganic oil generation. There are currently two influential inorganic oil generation theories: one is Gold’s mantle degassing theory; the second is Fischer-Tropsch geological synthesis theory. The theory of inorganic oil generation began to rise in my country in the 1980s, and Zhang Jinglian, Li Qingzhong, and Du Letian are all representatives of this theory.
  The theory of mantle degassing was proposed by Gold et al. based on the solar system and the Earth’s formation and evolution model. It is believed that there are a large amount of methane and other non-hydrocarbon resources in the deep earth, and a large amount of reduced carbon is released by heating in the deep crust through geological history. With various changes over time, this methane migrates upwards. When there are mantle plumes and deep faults, the methane gas can be released through faults, volcanic activity or crustal movement.
  The main evidence of the theory of petroleum inorganic genesis can be divided into the following three aspects:
  (1) The process of inorganic hydrocarbon generation has been achieved by the use of inorganic synthesis in the laboratory;
  (2) Celestial body spectra, meteorites, volcanic gas and magma Evidence of hydrocarbons has been detected in the rocks;
  (3) The optical activity of petroleum can be synthesized by non-optically active substances, and porphyrin can also be synthesized inorganically.
  The book “On the Inorganic Causes of Petroleum” written by Zhang Jinglian in 2001 “declared the end of the theory of organic origin of oil and gas.” Academician Li Qingzhong raised 22 questions about the theory of organic oil production. There are theoretical and practical aspects of these doubts, and each of these questions hits the point. Professor Du Letian was the first scholar who advocated the effect of the earth’s exhaust gas. He proposed the mantle juice theory in 1987, and believed that “mantle juice comes from the powerful hydrogen flow in the earth’s core and radiates outward.” He believes that the crustal gas circle contains huge natural gas resources that can be exploited on a large scale by mankind. It is worth noting that the theory of hydrogen and hydrocarbon expulsion proposed by Professor Du Letian can reasonably explain many geological disasters and natural disasters.
  Petroleum is a complex mixture of hydrocarbons and non-hydrocarbons. The main components are oil (hydrocarbons), colloids (viscous semi-solid substances), asphaltenes (dark brown or black brittle solid substances), carbonaceous ( Non-hydrocarbon), the main constituent elements are: C, H, O, N, S. Since petroleum does not have a unified and clear molecular chemical formula and its composition is very complicated, its formation process and mechanism must be very complicated. Petroleum organic genesis theory occupies a dominant position in today’s petroleum geology theories, but scholars have also been conducting research on the inorganic genesis of petroleum. Although the various indicators of organic oil generation theory can objectively guide the practice of finding oil, they may have larger problems (the laboratory cannot prove that organic matter can generate oil at low temperatures), and it has a guiding role in oil and gas exploration. It can only be regarded as a practical act of summarizing objective laws to guide production.
  The current debate on “organic” and “inorganic” has been going on for more than 100 years. At present, some experts and scholars have begun to agree that there are deep crust materials in individual natural gas reservoirs, that is to say, some scholars have agreed that natural gas is a combination of organic and inorganic materials. The product. On the exploration of the source of oil, we still need to continue to face the evidence we have with a scientific and realistic attitude, face up to the problems faced by the theory, and believe that the mystery of the source of oil will eventually become clear and clear one day.