Sequence stratigraphic analysis and subtle trap identification of Silurian around well HT1, Bachu Uplift, Tarim Basin

Based on sequence stratigraphy and slope-break theories,Silurian stratum around well HT1 in the Bachu Uplift of the Tarim Basin has been divided into 2 3rd-grade sequences (SQ1 and SQ2) and 6 systems according to the analyses of drilling,logging,seismic and core data collected from the study area.Studies of ancient landscape and sedimentary facies have indicated that,from the late Caledonian to the early Hercynian,the Tarim Basin contracted severely and the Hetianhe ancient uplift rose to form northward slope (mainly of tide flat facies).Geologic conditions for the formation of lithologic trap in the study area have been concluded and 4 configuration traps have been identified.