Diagenetic characteristics of hydrocarbon source rocks in Lower Permian Maihanhada Formation of Ejin Banner area，western Inner Mongolia

In order to study diagenetic characteristics of Maihanhada Formation in the study area with two measured sections of Hangwula and Maihanhada as examples，the authors employed such means as thin section identification, cathode luminescence, X-ray diffraction analysis, inclusions temperature testing and scanning electron microscope in combination with the data of organic geochemistry. The study result shows that the main sandstone in this area is feldspar sandstone-lithic sandstone. The diagenetic characteristics of Maihanhada Formation show that this set of sandstones is at the early stage of the middle diagenetic period. The early diagenetic compaction was the major effective factor leading to the wreckage around the original pores，whereas the dissolution was one of the significant factors for the formation of the secondary pores and improved the reservoir property to a certain extent.