Research On The Type Of Sedimentary Facies And Sand Body Distribution Of Qianfoya Formation Of Middle Jurassic In Bazhong Area, Sichuan Basin

Through the investigation of the study area,starting from the PingXizhen,LiuBaxiang,LiXiyan and so on,combined with the distribution of drill core in the key wells area,which summed up the Bazhong sedimentary system and the law of sand body distribution.By observing the color of rock in the study area,the sedimentary characteristics of different periods can be summed up.The color of the mudstone is mainly red,purple red and gray green,while the red mudstone section is found less in the middle section of the thousand Buddha cliff,but more in the thousand and the thousand three.In the sedimentary period,the laker level changes from shallow to deep and then shallower again,so the sedimentary facies of delta front and shore-shallow lake in the basin are influenced greatly by the change of water body.Because the bottom topography in the lake basin is flat and the lake are frequent fluctuation,the delta deposit extend far to the lake basin,sedimentary differentiation is perfect and the delta plain,delta front and prodelta do not have obvious superimposition.The tectonic movement is relatively weak in Qianfoya sedimentary period,under this context,the filling of sediments has slowed the slope of sedimentary basins in this area,which is the basis for the development of deltas.According to the characteristics of sedimentary microfacies,the distributary channel of the delta is abnormal,but the mouth bar is very undeveloped.