Charging And Adjustment From NO.1 Area Of Central Junggar Basin

The hydrocarbon accumulation in the superimposed basin is characterized by multiple stage hydrocarbon expulsion,accumulation,adjustment and reconstruction.It is one of the key scientific problems that must be solved for effective reservoir exploration in petroliferous basins represented by the Junggar Basin in West China.Selecting the typical reservoirs in the superimposed basin to reconstruct the history of the adjustment is the only effective way to solve this key scientific question.The Moxizhuang area is located in the western part of the Mosuowan Uplift in the Junggar Basin.Previous studies have shown that Moxizhuang hydrocarbon reservoirs are affected by the differential tilting between the fore-deep and the fore-bulge of the foreland basin.The oil and gas transporting along the sand-body from south to north is the basic characteristics of adjustment.Based on the historical analysis of tectonic evolution in the Moxizhuang area,this paper conducted a geochemical parameter tracing study of hydrocarbon migration and then carried out a two-dimensional simulation of hydrocarbon migration and accumulation under the control of tectonic evolution pattern,and finally reconstructed the history of hydrocarbon migration and accumulation of Block 1 of central Junggar Basin.The results show that Moxizhuang area has always had low-amplitude structural traps before the Paleogene.Since the Neogene,the Himalayan movement has caused the basin to tilt to the south and the structural traps have disappeared.The tracer analysis of hydrocarbon geochemical parameters shows that the lateral migration of oil and gas along the unconformity surface and the permeable sand body is very limited(<5km),and more manifests as vertical transport along different levels of strike-slip faults,which leads to the general accumulation of oil and gas in the sand bodies that are communicated by faults in contrast to previous research conclusions.The hydrocarbon migration simulation further indicates that the adjustment of tectonic evolution leads to the westward migration of oil and gas from mature source rock,which has a certain driving effect on the accumulation of oil and gas to Moxizhuang area,but in general,the Permian source rocks are the main source rock of this area,while the contribution of the Jurassic source rock is limited,consistent with the results of the previous research.Based on the above work,the model of vertical and close migration and accumulation of oil and gas along the strike-slip fault in this area is established.