Duan Y.,Key Laboratory of Petroleum Resources Research of Gansu Province |
Duan Y.,CAS Institute of Geology and Geophysics |
Duan Y.,University of Chinese Academy of Sciences |
Zhao Y.,Key Laboratory of Petroleum Resources Research of Gansu Province |
And 11 more authors.
Natural Gas Geoscience | Year: 2014
Light hydrocarbon analytical technology, being an important research method of petroleum geochemistry, was used widely in the exploration and exploitation of oil and gas reservoirs. By reviewing the previous studies, the present research situation, problems and development trend of light hydrocarbon geochemistry were systematically analyzed. At present, there are mainly two theoretical systems of thermal cracking and catalysis in light hydrocarbon formation mechanism. The former emphasizes on the role of thermal kinetics during the process of light hydrocarbon formation, and the latter stresses the catalysis of transition metals. However, there are still some limitations in the two theories. The thermal cracking neglects the catalysis of transition metals from sedimentary rocks to light hydrocarbon formation, and the catalysis ignores the thermodynamic excitation effect on the catalytic activity. Light hydrocarbon plays an important role in the application of petroleum geochemistry, such as the investigation of natural gas origin, the determination of organic matter type and the depositional environment of source rock, the indication of oil and gas maturity, oil-source correlations, the determination of secondary alteration and the migration of oil and gas, the preservation condition and the connectivity analysis of oil and gas reservoirs. Research trends in light hydrocarbon geochemistry theory are to strengthen basic research of light hydrocarbon genesis theory, and to attract attention to other discipline theoretical advantages. The applied research of light hydrocarbon should be combined with the methods of individual compound isotope with biomarker compound analyses and should fully consider the impact of the factors such as geology and light hydrocarbon analysis methods. ©, 2014, Science Press. All right reserved.
Ji L.-M.,Key Laboratory of Petroleum Resources Research of Gansu Province |
Ji L.-M.,CAS Institute of Geology and Geophysics |
Ma X.-X.,Key Laboratory of Petroleum Resources Research of Gansu Province |
Ma X.-X.,CAS Institute of Geology and Geophysics |
And 4 more authors.
Natural Gas Geoscience | Year: 2014
The pore size, surface area and methane adsorption isotherm of clay-rich rocks are measured. Clay minerals mainly contain micropore of 3-100nm, and have two main intervals of 3-6nm and 20-70nm. Smectite is of micropore-dominant. Illite-smectite mixed layer developed micropore and macropore in the same time, and kaolinite, chlorite and illite are of mesopore and macropore. Smectite, illite-smectite mixed layer and kaolinite are the polyporous type, their total pore volume and surface area are more than 0.04 mL/g and 11.47m2/g, respectively. Adsorption capacity of clay rocks is quite different. The maximum methane adsorption capacity of smectite, illite-smectite mixed-layer, kaolinite, chlorite, illite, sandstone and quartzite in the granularity of less than 270 mesh sequentially are 8.12 mL/g, 3.66 mL/g, 2.70 mL/g, 2.28 mL/g, 1.72 mL/g, 0.97 mL/g and 0.70 mL/g. Surface area of clay minerals depends not only on the total pore volume and porosity, also on the pore size distribution closely. There is a good linear relationship between the micropore volume of clay minerals and the maximum amount of methane adsorption. Therefore, the micropore volume of shale reflects its adsorption capacity for natural gas. The adsorption capacity is controlled by the development degree of internal micropores, in particular less than 20nm micropores. The difference of clay minerals in morphological structure, pore size and porosity results in the differences of their adsorption capacity. This difference is associated not only with the clay type, also with its causes and the diagenesis experienced.