Sequence Stratigraphy Of Permian-Jurassic In Santanghu Basin, Xinjiang

This thesis has studied primitively continental sequence stratigraphy of Santanghu basin with the fundamental principle and methods of classic sequence stratigrahy, and got some elementary conclusions.Santanghu basin, located in the joint between the kazakhstanian plate and the Siberian plate, has the pre-Permian folded basements of volcanic-sedimentary rocks. The Santanghu basin has three formation and evolution stages, i.e. formation and evolution stage of fault-depression basin in Permian, formation and evolution stage of depression basin in Triassic-Jurassic-Cretaceous, formation and evolution of Neozoic basin.This paper provides a new understanding on strata in Santanghu Basin through sequence stratigraphic technique, with lots of seismic section.According to the synthetical study of seismic section, well logging, sampling data, sediment system, character of sediment filling, the sequence stratigraphic framework has been set up during the Permian to Jurassic in the Santanghu basin, which include two basin-fill sequence which are fault depression basin-fill sequence of the Permian, and depression basin-fill sequence of Trials-Jurassic. The fault depression basin-fill sequence of the Permian can be divided into 3 sequences. The depression basin-fill sequence of Trias-Jurassic can be divided into 3 tectonic sequences, which include 7 sequences.In the fault depression basin of the Permian, the LST runs short of in the heartland of the lake, however, it is abundant in lakeshore area, it is mainly comprised of underwater gravity sediments and dolomite sediments of shallow lake facies. Vertically, LST consists of small scale progradational or aggradational parasequence sets; whereas, TST is comprised of mudstone of tuff and dolomitic mudstone of semi-deep lake facies in the area of lake basin, retrogradational delta complex can be found at the marginal region of the basin; HST is mainly comprised of shallow lake facies sediments system, with aggradational and progradational parasequence set stacking pattern.In the depression basin of Trias-Jurassic, LST consists of sediment gravity flow, alluvial fan-braided river sediments and (fan) delta-lacustrine facies sedimentary systems, with small scale progradational or aggradational parasequence sets; TST mainly consists of mudstone of lake, with retrogradational parasequence sets; HST is mainly comprised of shallow lake facies sediments systems, meandering riversedimentary systems and progradational delta sedimentary systems, with aggradational and progradational parasequence set stacking pattern.It concluded that oil and gas is distributed in the margin of lake in LST and in the heart area of lake in HST; whereas, it is distributed in the heart area of basin in LST.Affected by the regional pressing role in late Hercynian and the late Yanshan and Himalayas movement, oil & gas accumulation had changed in basin. Oil & gas is mainly located in the front of the southwest thrust and nappe tectonic belt and north side of syncline in the fault depression basin of the Permian. Of course, it mainly located in the southwest thrust and nappe tectonic belt and north side of syncline in the Tiaohu depression, and in the heart area of Malang depression.