A Method for Observation of Characteristics of Hydrocarbon Generation Materials in Electron Probe Thin Sections of Black Source Rock by the Reflected-light Viewing System of a Polarized Optical Microscope

Abstract

BACKGROUND The hydrocarbon generation materials in thin sections of black source rocks (such as black mudstone, oil shale), from the Chang 7 Member of the Upper Triassic Yanchang Formation in the Ordos Basin, are often partially or entirely black under the transmitted-light viewing system of a polarized optical microscope, because they are covered by black organic matter (such as oil, asphaltene) or opaque. OBJECTIVES To put forward an effective method to observe the hydrocarbon generation materials in thin sections of black source rock. METHODS A method for observation of characteristics of hydrocarbon generation materials of black source rock was proposed, using the reflected-light viewing system of a polarized optical microscope on electron probe thin sections. RESULTS The method can overcome the problem that hydrocarbon generation materials in thin section were covered by black organic matter or were opaque. The size, shape, structure, distribution of hydrocarbon generation materials and composition can be entirely and clearly observed in thin sections of black source rock. CONCLUSIONS In the long-term test, it has been proved that the method for observation of characteristics of hydrocarbon generation material in thin sections of black source rock by the reflected-light viewing system of a polarized optical microscope is simple and effective, and can be easily used in the study of hydrocarbon generation of tight oil and shale oil.

Keywords

• black source rock
• black organic matter
• hydrocarbon generation material
• reflected-light viewing system of polarized optical microscope
• electron probe thin section