塔里木盆地塔中南坡台缘带油气成藏条件

利用最新地震、测井资料,综合运用等时地层格架、构造解析和沉积演化等方法,识别塔中南坡台缘带的具体位置和形态,分析塔中南坡台缘带的结构特征及不同区段油气成藏条件.研究表明,塔中南坡台缘带是早奥陶世末期至晚奥陶世早期形成的大型复合型台缘带:台缘带东段是在上奥陶统沉积前遭受长期剥蚀而形成的复杂断裂台缘带;西段为在上奥陶统良里塔格组沉积时沿缓斜坡台缘带发育的台地边缘礁滩复合体,形成碳酸盐岩沉积台缘带.塔中南坡台缘带横向上具有分段性,可分为构造和沉积特征各异的6段,其中第Ⅰ段和第Ⅱ段是超覆三角带和削截三角带叠合部位,岩溶和岩性储集层发育,第Ⅴ段是台缘礁潍发育区段,这3个区带是塔中南坡油气勘探的主要目标.

Reservoir-forming conditions of platform margin belt in southern slope of Tazhong, Tarim Basin

Based on the new seismic and logging data, this paper identifies the location and shape of the platform margin belt in Tazhong, Tarim Basin and studies its structural characteristics and reservoir-forming conditions using isochronous sequence framework, structural analysis, sedimentary evolution and other methods. The platform margin belt is a large composite slope break belt formed from the end of the early Ordovician to the early of Late Ordovician. Its east section is a complicated faulted slope break resulted from erosion before Late Ordovician, and its west is a carbonate sedimentary slope break in which the platform margin reef flat complex was developed in the Lianglitage Formation of the Upper Ordovician. The belt can be divided into six parts with different structural and sedimentary characteristics. The first and second parts are the superimposed segment of the on-lap trigonal zone and the erosional trigonal zone, in which karst and lithologic reservoirs were well-developed. Platform margin reef flats were well-developed in the fifth part. These three zones are the main exploration targets.