ORGANIC INCLUSIONS AND THEIR RELATIONS WITH OILS AND GASES

Abstract

Based on some typical examples, this paper systematically reviews the formation mechanism, geological implications and methodology of organic inclusions as well as their relations with oils and gases. Organic inclusions present a direct mark of primary and secondary migration of oils and gases. The authors put forward the methods and results of investigation and recognition of organic inclusions in this paper. In our research work, the following instruments and techniques were mainly used: polarizing microscope, fluorescent microscope, micro-heating-cooling stage and component analysis. By means of polarizing microscope, the characteristics of organic inclusions, such as their shape, size, distribution, colour and refrigeration, can be known, and furthermore we can divide organic inclusions into two classes. A fluorescent microscope can be used to make ultraviolet scanning on a single inclusion, measure its wavelength and draw a fluorescence spectrum. Heating and cooling experiments show that the measurement of homogenization temperatures is complex and the homogenization temperatures of organic inclusions are 10-20℃ lower than those of inorganic salt solution inclusions for the same period. In the cooling process, organic inclusions hardly freeze and such phenomena as deformation of organic inclusions and pulsation stopping of gaseous bubbles can be observed. In component analysis, we can realize the proportion of gas components in each soluble organic constituent in the total extract. In gas and oil exploration, a knowledge of organic inclusions is vital to expanding the application of organic geochemical indices, understanding the geological time and direction of oil and gas migration, confirming the formation stages of oil and gas pools, ascertaining the properties, origin and evolution stages of oil-field waters, and directly guiding the exploration of oil and gas pools.