Simple Analysis Of The Relationship Between The Gas Migration And The Migration Systems In Upper Paleozoic Of Ordos Basin

This thesis researches on the migrating characteristics and differences among porous sandstone and mudstone(S & M), fractured S & M, faults, based on the regional geological data in Upper Paleozoic of Erdos Basin. Observing cores and the pore structure of casting thin sections, combining analysis of conventional porosity and permeability prove the result. On this basis, types of migration system in Upper Paleozoic of Erdos Basin are classified, and migration systems’distributions in Upper Paleozoic of Erdos Basin are studied. At the same time, tectonic evolution and hydrocarbon migration characteristic have also studied. Conclusions as follows:(1) The migrating characteristics of different migration mediumsIn porous S&M, connectivity and permeability in the parallel level are generally better than that of the vertical. In fractured S&M, permeability in the direction of fracture is much larger than that of porous S&M around the fractured S&M. In the plastic compaction segment, the migrating characteristic of fault is generally poor. While in the elastic-plastic compression segment and rupture segment, the migrating characteristic of fault is generally good.(2) Types of the migration system in Upper Paleozoic of Erdos BasinMigration systems of the gas in Upper Paleozoic of Erdos Basin mainly are classified into the pore migration system, the fracture migration system and a small amount of the fault migration systems.(3) Distribution characteristics of the migration system in Upper Paleozoic of Erdos BasinWhen the buried depth is less than 2200 meters, the porous migration system plays a major role; while the buried depth is greater than 2200 meters, the fractured migration system plays a major role.(4) Research of tectonic evolution division and migration characteristic of the gas in Upper Paleozoic of Ordos BasinEastern of Baersai-Etuokeqian Banner-Wuqi-Fuxian has always been in a relatively stable region during the process of tectonic evolution in Upper Paleozoic of Ordos Basin, and the migration direction of the gas in this region doesn’t change. Thus, the gas can accumulate in Upper Paleozoic of Ordos Basin easily. Overlapping the gas reservoirs of Upper Paleozoic and ancient and modern similar area, and the degree of coupling is obviously high. So, the overlap is the mainly region of the gas reservoir in Upper Paleozoic since the Middle Jurassic. While the unconventional gas distributes along the relatively low region.