塔中隆起晚奥陶世古地貌及其沉积相特征

Late Ordovician palaeogeomorphology and its sedimentary facies characteristics in central Tarim uplift

塔中Ⅰ号断裂带古地貌及其沉积相是控制塔中地区晚奥陶世台缘相带和大型生物礁油气藏发育的主要因素,在该区寻找相似的生物礁发育带具有重要的勘探意义。分析塔中隆起上奥陶统沉积体系地震反射结构,选择距古隆起顶面最近且全区易追踪的沉积界面作为近似古水平面,恢复了塔中隆起及其邻区上奥陶统沉积前的古地貌,并将其划分为6个单元:台内高隆、台内缓坡、台地斜坡、陆架斜坡、陆架坡折和深海盆地,其中分别发育局限台地相、开阔台地相、台地边缘相、开阔陆棚相和深海槽盆相。研究表明,台内缓坡带具有与塔中Ⅰ号断裂带相似的古地貌及沉积相特征,且主要分布在塔中隆起南斜坡并向和田河东延伸一带,以及西部沿吐木休克断裂一带和顺托果勒低隆段两侧,可能是生物礁油气藏勘探的重要目标。

The palaeogeomorphology and its sedimentary facies in central Tarim I fault belt is the major factor to control the development of Late Ordovician platform margin and large-scale reef reservoir in central Tarim area,looking for similar reef development belt is important for exploration in this area. Seismic reflection structure in Upper Ordovician sedimentary system was analyzed,the sediment interface which is the closest to paleo-uplift top and is easy to track was selected as palaeo-water level,and the palaeogeomorphology for central Tarim uplift and its nearby area in pre-Upper Ordovician sediment was recovered and it was divided into 6 units,inner-platform uplift,inner-platform gentle slope,platform slope,shelf slope,shelf break and deep sea basin,and the local plateau facies,open plateau facies,platform edge facies,open shelf facies and deep sea trough basin facies were developed in it. The studies show that like central Tarim I fault belt the inner-platform gentle slope belt has similar palaeogeomorphology and sedimentary facies characteristics,and it mainly distributes in south slope of the central Tarim uplift and in the eastward extending area of Hetian river,and along the western Tumuxiuke fault belt and the two flanks of Shuntuoguole low-uplift,it may be an important target for reef reservoir exploration.