Dolomitic tight oil reservoir in west slope of the Mahu Sag has become an important exploration domain in the Junggar Basin in recent years.Based on characteristic analysis of the dolomitic rock of the Fengcheng Formation in Wuxia area

we summarized the controlling factors of dolomitic tight oil reservoir development

and concluded that high quality source rocks occur in the Fengcheng Formation

and the distribution of‘sweet spot’was jointly determined by lithology

porosity and fracture development.According to the association of matrix porosity and fracture

the‘sweet spots’were divided into porosity type

fracture type and porosity-fracture type.The influences of lithology

porosity

thickness

surrounding rock of 'sweet spot’to seismic responses were studied through seismic petrophysical analysis and seismic forward modeling on sensitive parameters.On this basis

effective tight oi‘sweet spot’prediction methods were selected and seismic multi-attribute analysis technique was used to predict the distribution of favorable dolomitic rocks.The distribution of favorable porosity was predicted by using acoustic impedance inversion and stochastic simulation inversion technique.The distribution of favorable fractures was predicted by using mineral composition brittleness index evaluation method and ant tracking technology.The‘sweet spots’of type-Ⅰ

type-Ⅱ and type-Ⅲ were identified based on integration of lithology

porosity

fracture prediction results.These study results provide the basis for further tight oil exploration in the region.