Sedimentary Facies Analysis Of J₁s₂¹in Sha Wodi Region Of Junggar Basin

Shawodi is located in northwest of1Block, Central Junggar Basin, lower JurassicSangonghe lithologic reservoir is currently the uppermost exploration target. For theuncertainty of sedimentary facies and source direction of Shawodi Lower Jurassic UpperSangonghe2（J₁s₂¹）, focusing on researching the relationship among the resolution sequencestratigraphy, sedimentary facies and superimposition of sand bodies. The main results are asfollows:（1） According to the rhythm of sand body and logging curve characteristics, sequenceinterface properties of J₁s₂¹is defined. The top interface is flooding surface and the bottominterface is Medium-term cycle interface. The J₁s₂¹is divided into three short-termsequences （SSC1, SSC2, SSC3） and identified two short-term cycle interface and three kindsequence structures: normal cycle, inverse, Symmetrical cycle.（2） Combining petrology features, sedimentary structure and logging facies,sedimentary facies of study region is cleared as delta facies, and sedimentary microfacies ofthe subaquatic interdistributary bay, underwater distributary channel, mouth bar, sheet sand,far sand bar and prodelta mud are developed.（3） The distribution characteristic is determined by sand ratio, seismic reflectioncharacter and seismic attribution. Channel sand distributed in the vast area of northwest andsouth; Mouth bar developed in the southern of well sand3and the study region; Sheet sanddistributed in the southern; Far sand bar developed in the southwestern of study region.（4） According to research results of sedimentary facies, the vertical combination ofsuperimposed pattern of microfacies was summarized such as "multiphase underwaterdistributary channel, the bar deposited on the river" and "the river deposited on the bar ".