塔里木盆地巴楚—塔中地区寒武系层序地层特征

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

伴随塔里木盆地深层碳酸盐岩的油气勘探,寒武系地层已经成为研究的重点。该文主要通过对岩石地层、测井地层、生物地层、地震地层等资料的综合分析,将塔里木盆地巴楚—塔中地区寒武系地层划分为3个二级层序,SSQ1对应下寒武统,SSQ2对应中寒武统,SSQ3对应上寒武统。其中,巴楚地区3个二级层序发育完整,塔中地区塔参1井为基底隆起高部位,只发育SSQ2和SSQ3。二级层序的形成受控于构造演化的周期性,反映了寒武系3次大的海进—海退,在沉积演化上经历了3个阶段,即早寒武世的潮坪—局限台地—蒸发台地、中寒武世的开阔台地—蒸发台地、晚寒武世的局限台地的沉积序列。

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.