Sequence Stratigraphy And Diagenetic Dynamic Of Jurassic In Junggar Basin

Junggar basin is one of the main petroliferous one in the west of China. There are abundance oil and gas resources which have been found through exploration for 50 years. With the increase of the difficulty and complexity of the oil-gas exploration, the exploration still confronts many geological questions, that's starving for resolving the sequence stratigraphy on whole Junggar basin, researches of diagenetic rules and reservoir sedimentary characteristics of the stressing formation(Jurassic) of the important area(the central basin.),the forming mechanism of stratigraphic trap and complex trap.Based the former achievements on geology and integrated applying the data of geology and physical geography, the sequence stratigraphy framework and system tracts architecture in Junggar basin were established by identifying, tracing and correlating sequence boundaries. The stratigraphy in Junggar basin could be divided into four first-order sequences (MegaSequence) , nine second-order sequences (SuperSequence) and twenty-nine third-order sequences (Sequence) . The analysis of interior constitution and system tracts characters of Jurassic sequence sratigraphy was stressed, and the models were built. In the frame of sequence sratigraphy, the sedimentary facies types and distribution were confirmed in the system tracts, the depositional system types and main sedimentary provenance were clarified. To the central important area(the 1^st region of the central basin), the sedimentary micro-facies of the Second Sandstones member of Sangonghe Formation were explained in the II III sequences of Jurassic. In the HST(J₁S₂²)of the II sequence, it was characterised by the large-scale braid delta-front sediment in the east of the 1^st region of the central basin. The provenance came from Che-Mo low uplift (proved by well Zhuang 1), the distributary sediment was abundance, but the mouth bar few, accompanying the slump turbidite in the same time. In the west part, the sediment material of the fan delta came from Zhong-Guai uplift (proved by sha 1 well). Sand body in the LST(J₁S₂¹)of the III sequence J₁S₂¹ was delta front deposits of meandering river, which was the most stable sand in the Jurassic with sand thickness between 38-64m in 1^st region of central basin, Ma-Qiao area and Zhong-Guai area.The study applies basic theory of "dynamic diagenesis" into diagenesis researches was preceding. The diagenesis material was the inherence factors that influenced dynamic diagenesis, which was mainly showed by resist-press resist-hot the activity of chemistry of the rock. "The three fields", were the mainly outside factors that influenced dynamic diagenesis, the influence of geological time on diagenesis was not obvious. The diagenetic water was main factor in the reaction of chemical diagenesis. The thesis also discussed the synthetic influence of above factors on dynamic diagenesis in detail and graded dynamic diagenesis into three types, which were respectively thermally dynamic diagenesis, tectonically dynamic diagenesis and hydrokinetic diagenesis, and then the types of diagenesis controlled by dynamic factors had been studied: 1 thermally dynamic diagenesis, clarified the ration relationship by the conception of the thermally evolving track and the thermally maturity, 2 tectonically dynamic diagenesis, changed the porosity of reservoir mainly by tectonically movement;3 . hydrokinetic diagenesis, changed the physical and chemical properties resist-press intensity of the rock by the participating of liquid.