Research On The Effect Of Miocene-Pliocene Tectonic Movement On Hydrocarbon Accumulation In Southeast Asian Island Arc

Based on the background of the activities of the Mesozoic-Cenozoic Southeast Asia plate convergence zone,the island arc belt is divided into forearc basins outside the island arc and back-arc basins inside the island arc,and the study area is divided into the Sumatra arc zone and Java Island arc zone.Based on the study of the forearc and back-arc basins tectonic evolution of the arc belts of Sumatra and Java,learn basins formation,compare the similarities and differences between them,and summarize the source rock characteristics of the basins.In studying the tectonic evolution of the basin,it was discovered that the island arc zone had undergone regional tectonic movement in the Miocene-Pliocene.After analyzing the effect of this tectonic movement on basins,it was found that this period of tectonic movement was mainly manifested as a compressional phenomenon and resulted in the uplift reversal of basins and orogeny.The tectonic movement of Sumatra is stronger than that of the Java.The tectonic activity of the Central Sumatra Basin and the South Sumatra Basin are strong.The tectonic activity of the West Java Basin is weak,and the East Java Basin and the North Sumatra Basin are weaker.This tectonic movement corresponds to the formation period of traps.Therefore,it has an important influence on hydrocarbon accumulations.In the plane,the structural movement is more intense in the basin where the lateral migration distance of oil and gas is farther.In vertical,the distribution of oil and gas is jointly determined by tectonic activity and stratigraphic development.The hydrocarbon migration in the basins with strong tectonic activity is far,but the preservation condition of oil and gas migrated to Pliocene are poor.The oil and gas in the basin are mainly concentrated in the Miocene.The hydrocarbon migration in the basin with weak tectonic activity is near,but the preservation condition of oil and gas migrated to Pliocene are good,and the oil and gas in the basin is mainly concentrated in the deep Eocene-Oligocene strata.Due to the lack of the Eocene-Oligocene strata in the North Sumatra Basin,the oil and gas are enriched in the Miocene-Pliocene strata.In traps,the proportion of oil and gas related to the structural traps in Sumatra basins with strong tectonic activities is significantly larger than that in the Java basins with weak tectonic activities.The above conclusions have been verified in the anatomy of the South Sumatra Basin and the East Java Basin.Finally,based on the understanding of the effect of the Miocene-Pliocene tectonic movement on hydrocarbon accumulation,combined with exploration and development conditions and the development of the Miocene reef limestone,the South Sumatra basin is considered to be the focus of the next exploration field in the study area.