塔中卡塔克隆起南北坡上奥陶统礁滩地震识别与储层预测

卡塔克隆起上奥陶统良里塔格组沉积时期为大型碳酸盐岩孤立台地。通过地震地质解剖并结合钻、测井成果,其南、北坡的地震相—沉积相模式可划分为陆棚—盆地→台缘斜坡→台地边缘→开阔台地沉积体系。在台地边缘区可识别出生物礁、粒屑滩和礁间洼地亚相,礁滩体具有纵向多个叠置"塔式"结构、横向退积—加积迁移特点,表明海平面升降控制了礁滩体的阶段性生长。采用模式识别、古地貌识别、属性识别等多种方法可进一步圈定礁滩体分布范围。预测结果认为,北坡西部为台地缓坡边缘主要以生屑、砂屑滩、鲕粒滩相发育,中部台缘高陡斜坡生物礁相发育,而南坡于卡2区块西北部及卡1区块南部台缘礁丘和浅滩发育,具有形成串珠带状分布的生物礁滩型油气田(藏)条件。

Seismic identification and reservoir prediction of reef flat of Upper Ordovician in northern and southern slopes of Katake Uplift,middle Tarim Basin

When the Lianglitage Formation of the Upper Ordovician deposited, the Katake Uplift in the Tarim Basin was a large-scale isolated platform of carbonate rocks. According to seismic geology as well as drilling and logging data, the seismic and sedimentary facies of the southern and northern slopes were classified as shelf-basin, marginal slope, platform margin, and open platform depositional systems. In the platform margin, the subfacies of reef, bioclastic bank and reef depression were identified. The reef-bank complex was featured by a stacked "tower" structure vertically, and retrograding-aggradational migration horizontally, showing that sea level changes controlled the phased growth of reef flats. Using pattern, palaeogeomorphology and attribute recognition methods, the distribution range of reef-bank complex was further delineated. Prediction results showed that the platform slope edge mainly developed bioclast, calcarenite beach and oolitic beach facies in the west of the northern slope, and the high and steep slope developed reef on the central platform margin; while on the southern slope, platform margin reefs and shoals developed in the northwestern Ka2 block and the southern Ka1 block, showing favorable conditions for the formation of beads-like reef-type oil and gas reservoirs.