矿物在油气形成过程中的作用

模拟实验结果表明，矿物组成对煤岩样品的模拟实验结果具有很大的影响，不同的矿物以及同一种矿物在不同的有机质热演化阶段，对有机质形成石油和天然气的过程均具有非常明显的影响:高岭土矿物在高温热演化阶段对有机质形成气态烃的过程具有一定的催化能力；碳酸钙（CaCO3）在中—低热演化阶段能抑制气态物质的形成，而在较高的热演化阶段则对煤生成气态物质的过程具有一定的催化作用；四氧化三铁（Fe3O4）在主要的模拟实验阶段对煤生成气态物质的过程均具有一定的催化作用；硫化亚铁（FeS）在低温热演化阶段对天然气的形成具有一定的抑制作用，而在高温热演化阶段则对天然气的形成具有较明显的催化作用；元素硫（S）在不同的热演化阶段对天然气的形成过程均具有非常明显的催化作用。矿物介质不仅对气态产物的产率有比较明显的影响，而且对液态产物的产率也有较明显的影响。模拟实验结果表明:高岭土和四氧化三铁（Fe3O4）在中、低温模拟实验阶段对“氯仿沥青A”的形成具有较明显的催化作用；硫化亚铁（FeS）在整个模拟实验的全过程中对“氯仿沥青A”的形成均具有明显的催化作用；碳酸钙（CaCO3）矿物对“氯仿沥青A”的形成具有明显的抑制作用；元素硫（S）对“氯仿沥青A”的形成具有非常明显的催化作用。

The Roles of Inorganic Minerals on the Oil and Gas Generating Processes

A coal sample was separately heated with kaolinite, CaCO3, Fe3O4, FeS , S and without any minerals at 250℃ to 600℃ in closed hydrous pyrolysis systems for 72 h. The results show that inorganic minerals have considerable affects on oil and gas generating processes. When coal was heated with kaolinite, the coal sample has higher bitumen "A" productivity than that of without kaolin at the highest bitumen "A" producing temperature, and this highest bitumen "A" producing temperature was moved from 400℃ (pure coal ) to 350℃ when kaolin was involved. The coal sample get its highest bitumen “A” producing at 400℃ when it was heated with and without CaCO3, but when coal was heated with CaCO3, it produce more bitumen “A” than that of without CaCO3 at 400℃. More bitumen “A” was produced at 250℃ and 300℃ and less of bitumen “A” was produced at 400℃ when the coal was heated with Fe3O4 than that of without Fe3O4. Similarly to kaolinite, Fe3O4 also make the coal moving its highest bitumen “A” producing temperature from 400℃(pure coal ) to 350℃.When coal was heated with FeS, the coal sample produce more bitumen “A” at all heating temperatures than that of without FeS, and the highest bitumen “A” producing temperature was also moved to 350℃(coal+FeS) instead of 400℃ (pure coal ).The coal produced less bitumen “A” at 350℃ and 400℃ and produced much more bitumen “A” 450℃ when it was heated with element S than that of without S. All the above observations indicate that inorganic minerals have both catalysis or delay affects on the oil generating process when the coal sample was heated with minerals. The coal has its highest gas productivity at 550℃ when it was heated with and without minerals. Comparatively, coal produced more gas when it was separately heated with kaolinite, CaCO3 and S and produced relatively less gas products when it was separately heated with Fe3O4 and FeS than that of without any minerals at high temperatures (from 400℃ to 600℃) .The laboratory studies previously have shown that the activation energies for thermal cracking of macr-organic molecules to light hydrocarbons are much higher than that in nature. These observations have led geologists believe that there must have some catalysts in nature which could lower the activation energies for oil and gas generating reactions and make oil and gas generating reactions happened or make them accelerated that not occurred or occurred slowly because of higher activation energies.This study indicates that thermal reaction is a very important factor during the oil and gas generating processes, but mineral catalysis or delay affects also play important roles in those processes. So, we should pay more attention on mineral catalysis/delay affects as well as thermal reactions on oil and gas exploration.