Discussion On The Distribution Characteristics And Its Hydrocarbon Potential Of Mesozoic Stratum In Southern East China Sea Shelf Basin

The East China Sea shelf basin is a Mesozoic-Cenozoic superimposedpetroliferous basin which lies on a Proterozoic-Palaeozoiccratonic basement. Theformer researches about its petroleum geology are mainly focused on the Cenozoic.Studies on Mesozoic strata distribution is seldom carried out because of lacking offundamental geological data. On the bases of geologic and geophysic data recentlygetting from seismic,drilling, gravity-magnetic and field outcrops, the paper dividesthe stratigraphic sequence, discusses the distribution characteristic of Mesozoicstrata,and studies basin tectonic,structure evolution and style, fault and igneous rocksdistribution in southern East China Sea shelf basin. Finally,on the bases of Mesozoicstrata correlation between marine and adjacent land,it could be drawn a conclusionthat the.Mesozoic strata are characterized by wide distribution and big thickness.There are5reflected waves with plane of unconformity in Southern part of TheEast China Sea shelf basin. The paper divide the area into5seismic sequencesaccording to characteristic of reflected waves characters, and combine with thedrilling data, stratigraphic sequences can be divided: Seismic SequenceⅠ(T20-T40)isQuaternary and Neozoic(Q＋N); Seismic SequenceⅡ(T40-T50)is Oligocene, Eoceneand Paleocene(E3+E2+E1);Seismic Sequence Ⅲ (T50-T60) is Cretaceous; SeismicSequence Ⅳ(T60-Tg) is Jurassic; Seismic Sequence Ⅴ(Below Tg) is pre-Mesozoic.The monolithic construction of southern part of The East China Sea shelf basin cansummarize the characteristic of “zoning in east and west and difference in south andnorth”.Based on the seismic data interpretation and magnetic-gravity anomaly, thepaper discuss the expanding characteristic of stratum and draw the conclusionthat:The Mesozoic of the East China Sea shelf basin is characterized by extensive distribution, big thickness and the main depositional body is in Keelung depression.This is controlled by the tectonic-sedimentary framework of “zoning in eastand westand difference in south and north”. The fault activities and magmatic activities of thisarea are strong in north and weak in sorth.There are3tectonic styles and12tectonicassociations in Mesozoic basin.According to the comprehensive analysis of seismic data, magnetic-gravityanomaly and drilling data, the source reservoir cap rock assemblage of Mesozoicgroup in The East China Sea shelf basin may be good. The middle-lower Jurassic canbe considered the main source rock, while the upper Cretaceous can be considered agood reservoir and the mudstone above is the cap.The paper infer that the slope belt ofMesozoic strata in the west of Minjiang depression may be the target area of oil-gasmigration and the Taipei low uplift in Paleocene is considered the favorable area ofOil-gas enrichment...