车排子地区构造-古地貌特征及其控砂机制

Structural-paleogeomorphologic features of Chepaizi area and mechanism of their control on sandbodies

邢凤存 陆永潮 刘传虎 向奎

Xing Fengcun Lu Yongchao Liu Chuanhu Xiang Kui

利用地震、测井及测试资料,采用回剥技术及剥蚀量的趋势分析方法,恢复了准噶尔盆地车排子地区下白垩统吐谷鲁群层序低位体系域、古近系层序低位体系域及新近系中新统沙湾组层序湖扩体系域的底界面同沉积期古地貌.并分析了3个时期古地貌特征及其对下切谷砂砾岩体、扇三角洲砂砾岩体及滩坝砂体的控制作用.在此基础上,总结了3个时期地貌控砂模式,认为吐谷鲁层序低位期具隆起区供砂,低隆起区和"梁"分砂,沟谷输砂,凹陷聚砂的特点;古近系层序低位期古地貌控砂机制与吐谷鲁层序低位期的相似,但沟谷输砂特点不明显;沙湾组层序湖扩期具坡折带控砂和低隆起区控砂的特点.

Seismic,log,and test data as well as the backstripping technique and trend analysis method of erosion restoration,were employed in the synsedimentary palaeogeomorphology reconstruction of basal boundaries of the lowstand system tracts(LST) of the Lower Cretaceous Tugulu Group sequence,the LST of the Paleogene sequence and the lacustrine expanding system tract of the Miocene Shawan Formation sequence in the Chepaizi area,Junggar basin.The paleogeomorphologic features of these three stages and their control on glutenite in incised valley,fan deltaic glutenite and longshore sandbody were analyzed.Based on the results of these studies,this paper summarizes the controlling patterns of the geomorphology on sandbody distributions during these three stages.The LST of the Tugulu Group sequence is characterized by sand supply from the uplift,diversion of the low uplift and "ridge",transportation along the valley,and accumulation in the sag.The LST of the Paleogene sequence shares the similar features with the Tugulu Group sequence except for the insignificant feature of transportation along the valley,while the lacustrine expanding system tract of the Miocene Shawan Formation features in control of slope-break zone and low uplift zone on transportation and deposition of sand.

10.11743/ogg20080112