The Evolution And Multi-phase Fluids Injection Of Sangmuchang-Jiudianya Structure, Southeast Of Sichuan Basin

Through the early decades of oil and gas exploration and research, people have already recognized that preserving conditions are the the main controlling factors of oil and gas exploration. Because the traditional static evaluation of preserving conditions can not truly response the mechanism of hydrocarbon accumulation, that it is necessary to study the hydrocarbon preserving conditions from the dynamic point of view.Studies have shown that the district has undergone multiple tectonic stages of the tectonic movement. That is the result of superposition of multi-phase tectonic movement. Before the early stage of Yanshan movement, the study area was made of relatively simple stretch and differential uplift and subsidence. The relationship between layers was accordant or disconformable connection. After Himalayan movement (76Ma), the study area was made of persistent compression and uplift-fold orogenesis, and accompanied by strong weathering erosion.Under multi-phase Tectonic movement, it results in the release and injection of multi-phase fluids. The infilling characteristics of Silurian, Ordovician and Cambrian strata are simple, but the fluid infilling stages of the Dengying Formation of Upper Sinian are relatively complex, the multi-phase fluid infilling characteristics are obvious. Fluids come mainly from the virgin rock of Silurian and Cambrian, as well as the underlying deep level of Dengying Formation of Upper Sinian.Multi-phase tectonic movements control the movements of the fluid and the hydrocarbon preserving conditions. Before the early stage of Mioce??19Ma), the fluids only move in the lower-group. The hydrocarbon of the lower-group totally has good preserving conditions. After the early stage of Miocene (19Ma), the movement of persistent uplift- erosion cause the erosion of territorial covering strata and the opening of discordogenic fault, and the latest quartz hydrothermal fluid and the hydrocarbon move to the surface. The good preserving conditions of early stage were caused serious damage, and the lower-group lose the hydrocarbon preserving conditions.