Tectonic-Lithofacies Characteristics And Predicted Favorable Exploration Target In Wu-Xia Area Of Junggar Basin

The Wu-xia faulted zone was located on the eastern of northwest Junggar basin, it was an zone of bruchfalten affected by multiphase tectonic activity, have many faults and its fold morphology were very complicated. In this article, the characteristics and the laws of distribution and their inherent-relationships of structure and sedimentary were studied. The relationship of tectonic facies and hydrocarbon accumulation was clarified. The favorable aims of exploration activity were pointed.On the basis of plan form and crosscutting relationship of the faults, two kinds of tectonic systems were developed in Wu-Xia area, one was strike north-east, and another was strike east-west, the first was developed early and control the structural framework of Wu-Xia area, after that three times longitudinal compress action was happed. According to the intensity of tectonic deformation, The Wu-xia faulted zone from north to south can be divided into the thrust faulted belt, the fault fold belt and the monocline belt. from east to west have three regulatory faults, Wuerhe fault fold belt, Wuxia thrust faulted belt and Xiahong fault fold belt. Base on that 9 secondary structural unit can be divided.Structural accommodation zone and the distribution of reservoir strata have intimate business connection. Usually, Structural accommodation zone was the source zone of arenaceous sediment. The Wu-xia faulted zone have 3 kinds of structural accommodation, concordant approach, concordant overlap and concordant colinearity.Apply the seismic facies analysis technology, the distribution law of sedimentary system was studied. According to the characteristics of seismic facies, drilling core and log data, the depositional border was classified, and then alternate the seismic facies to sedimentary facies. Finally, the controlling role of structure to sedimentary was analyzed. It is showing that time-transgressive different structural zone developed different sedimentary system; the thickness of sedimentary formation and lithic facies were different on the simultaneous lateral layer of growth fault; the expansive orientation of sedimentary system was controlled by the strike of fault; the sedimentary system developed differently became of the tectonic activity was differently; step thrust slip fault can built-up multistage fault fans. 6 kinds of tectonic lithofacies can be classified according to the connection of sedimentary and structure. Consider about the conditions of oil geology, it is justification that the delta front of Wuerhe anticline fan (middle alluvial fan), the delta plain of Wu-xia thrust zone fan (inner alluvial fan), the delta plain of Xia-hong folded zone fan (inner alluvial fan) and the delta front of slope fan (middle alluvial fan) were the range of profitability of hydrocarbon accumulation.