Study Of The Paleostructure Restoration Of The Early Paleozoic,Tarim Basin

The reservoirs of early Paleozoic in the Tarim Basin are the focus of petr-oleum exploration for long time.The restoration of the key tectonic change ofbasin tectonic framework and the depict paleostructure in the main petroleum accumulation period,it will be great significance for petroleum exploration.This study is based on seismic extrapolation method and supplemented byinterval transit time method.in the Tarim Basin,calculate the erosion thicknessof the key unconformities of the early Paleozoic both in qualitative and quantit-ative,then restore the key layer of paleostructure both in the middle Caledonia-n and the early Hercynian.Combined with seismic and well data,determine the unconformities T74,T70and T60dominance in the early Paleozoic. T74erosion phenomenon mainly occ-urs in the Tazhong area. T70is the first class unconformity,mainly developedin the central uplift belt,the south of it and the Tabei uplift area,the most ob-viously developed in the north of the Tazhong uplift. T60is widespread develo-ped in the Tarim Basin,erosion phenomenon mainly occurs in the Tabei uplift,Tazhong uplift and Tadongnan uplift.The erosion thickness results show that:T74mainly erosion area is in the T-azhong paleouplift and the Taxi’nan paleouplift’s erosion rate is80-200m.Theerosion rate of T70is200-400m in the Taxi’nan paleouplift.The Erosion rate inthe Tazhong paleouplift is400-1000m and800-1600m,some area is max to40-00m in the Tadongnan paleouplift,in the Tabei paleouplift is400-800m. The er-osion rate of T60in the Taxi’nan paleouplift is600-800m,in the Tazhong paleo-uplift is800-1200m and800-1400m in the Tadongnan paleouplift,800-2000m i-n the Tabei paleouplift.The restoration of the paleostructure results show that:the tectonic patternof the Tarim Basin is west area higher than east area in the middle Caledonia- n,the Tanggubazi depression and the Manjia’er depression are the sedimentationcenters in this era. In the early Hercynian,The up Ordovician and the Silurian-mid Devonian in the Tabei paleouplift were completely eroded.The up Ordovic-ian and the Silurian-mid Devonian were completely eroded in the Taxi’nan pal-eouplift.Only a small amount of Ordovician remain in the Tadongnan paleoupli-ft.The up Ordovician and the Silurian-mid Devonian missed in some part of t-he Tazhong central fault belt.