Tight Reservoir Formation Characteristics Of Permian In Tiaohu Sag,Santanghu Basin

The discovery of Permian Tiaohu formation tuff reservoir with high porosity and low permeability,provides a new direction and new ideas for tight oil exploration.Base on the tight oil exploration achieved of Tiaohu formation in Malang sag of Santanghu basin,We take Tiaohu sag as research object.Utilizing the geologic materials including the seismic,well logging and core,and the experimental data of the whole rock X-ray diffraction,thin section authentication and scanning electron microscope experiment,taking scientific geological research means,we study the volcanism feature,restore the original sedimentary paleo geomorphology of Tiaohu formation and predict the tuff thickness distribution of Tiaohu depression.In this study,we also compare the tuff features of Tiaohu sag with the Malang sag.The researches show that,(1)The volcanic edifices associate with faults and we have totally discerned five main volcanic edifices at beaded distribution.(2)Tiaohu sag sedimentary center of Tiaohu formation is located in the southern margin.In the southern margin of Tiaohu sag develops several sedimentary depressions and the deposit thickness is nearly 400 meters.(3)According to the evaluation standard of source rock,we divide the source rock of Lucaogou formation into four categories and the source rock quality of A and B categories is good.(4)In this study,we distinguish three types of structural style,including northwest fault fold type,central back thrust type and southeast ramp thrust type.(5)In this study we have predicted two favorable oil zones,which are Well Tiao8 south favorable zone and Well Tiao27 west favorable zone.