Sequence stratigraphy of Cambrian in Bachu-Tazhong area, Tarim Basin

Cambrian has been an important research aspect during the oil and gas exploration of deep carbonate in Tarim Basin. Based on the analysis of lithostratigraphy, logging stratigraphy, biostratum and seismic stratigraphy, Cambrian in Bachu-Tazhong area of Tarim Basin is divided into three second-order sequences. SSQ1 corresponds to Lower Cambrian, SSQ2 corresponds to Middle Cambrian, and SSQ3 corresponds to Upper Cambrian. These three second-order sequences developed well in Bachu area, while only SSQ2 and SSQ3 developed in Tacan 1 well which is located in the uplift in Tazhong area. The forming of second-order sequence is controlled by the cyclicity of tectonic evolution, which demonstrates that Cambrian experienced 3 times of large transgression- regression and 3 phase of verticallydepositional evolution:tidal flat- restricted platform-evaporation platformofEarlyCambrian, toopen platform- evaporation platformofMiddle Cambrian, and restricted platformofLate Cambrian.