塔里木盆地石炭系地震地层学研究

Seismic stratigraphic researches on Carboniferous system in the Ta limu basin

塔里木盆地石炭系为该区的主力生油层系。该系地层属半闭塞、局部非正常盐度的台地型滨浅海相沉积。根据层序地层学原理，该套地层可划分为Ⅰ、Ⅱ两个层序。Ⅰ层序属下石炭统；Ⅱ层序属上石炭统和下二叠统。Ⅰ、Ⅱ层序又可细分为6个亚层序，即Ⅰa、Ⅰb、Ⅰc、Ⅱa、Ⅱo、Ⅱc亚层序，Ⅱc亚层序属下二叠统。根据各亚层序的地震反射特征，可划分成4种类型的地震相。第1类是平行连续地震相；第！类是亚平行较连续地震相；第三类是斜交地震相；第Ⅳ类是不规则地震相。这4类地震相又可进一步细分成9个亚类型，并对应有12种沉积相。Ⅰb、Ⅱb层序的海进期开阔台地和局限台地相带为有利生油相带；Ⅰa低水位期形成的贫底扇、斜坡扇相带是最好的储集相带，Ⅰb海进初期形成的内碎屑岩、生物碎屑灰岩、针孔云岩所指示的滩相带是较好的储集相带。广泛分布的开阔台地相带、局限台地相带是良好的盖层。石炭系油气勘探有利地区按主次顺序是塔中一巴东地区，麦盖提斜坡中、西部，巴楚隆起，和田－策勒低凸，塔北斜坡和西南拗陷。

Carboniferous system in the Talimu basin is main source sequence. It is shoreinner neritic sedimentary series in platform was part enclosed and contained abnormal salt water in partial area. In terms of sequence stratigraphy theory, the sedimentary series can be divided into sedimentary sequence Ⅰ and Ⅱ. The sequence Ⅰ belongs in Lower Carboniferous, and the sequence Ⅱ includes Upper Carboniferousand Lower Permian. Sequence Ⅰ and Ⅱ can be subdivided into 6 subsequences:Ⅰ a, Ⅰ b, Ⅰ c, Ⅱ a, Ⅱ b and Ⅱ c subsequences. Subsequence Ⅱ c belongs in Lower Permian. According to their seismic reflection characters, the sedimentary series coversfour types of seismic facies: parallel continuous seismic facies, pseudo parallel con-tinuous seismic facies, oblique seismic facies and irregular seismic facies. Theseseismic facies can be subdivided into 9 subtypes and involve 12 kinds of sedimentaryfacies. The open and limited prograssive platform facies belts which are included inⅠ b and Ⅱ b subsequences are favourable source facies belts; the bottom and slopefan facies belts in basin which correspond to the Ⅰ a during low water period are thebest resbrvoir facies belts; the Ⅰ b beach facies belt consisting of clastic rock, bio-clastic limestone and needle-porous dolomite which were deposited during early pro-gression is quite good reservoir facies belt； the open and limited platform faciesbelts are good barrier layers. According to their importance, the favourable areas inCarboniferous hydrocarbon exploration are mid Talimu-Badong region, mid-westMaigaiti slope, Bachu riie, Hetian-Celei low uplift, Tabei slope and Southwest depression.