【摘要】 通过沉积学、地震学、地球化学等研究表明,塔河油田12区发育了海西早期岩溶作用,表现为中下奥陶统碳酸盐岩与下石炭统巴楚组不整合接触、溶塌角砾岩与暗河沉积的存在以及溶洞充填物Sr/Ba值存在的差异特征等识别标志,该期岩溶地貌可划分为岩溶高地、岩溶Ⅰ及Ⅱ级斜坡和岩溶盆地4类地貌单元,研究区主要处于岩溶Ⅱ级斜坡区。由于海西早期运动具有脉动式抬升的特点,因而发育了3套岩溶旋回,研究区主要发育第Ⅱ和第Ⅲ套洞穴层;该期岩溶平面上发育在上奥陶统桑塔木组尖灭线以北的地区,纵向上发育在中下奥陶统质地较纯的碳酸盐岩中,古地貌和断裂对该期岩溶具有根本的控制作用,同时岩溶作用所形成的裂缝和溶蚀孔洞是影响储层储渗性能的关键;最后综合上述成果建立了海西早期岩溶发育模式,并将其发展进程划分为快速抬升剥蚀阶段、三幕抬升岩溶发育阶段及下降改造阶段。更多还原

【Abstract】 It has been investigated in this paper that karst occurred in Block 12 of Tahe Oilfield during early Hercynian stage where unconformity interface exists between lower Ordovician carbonate and lower Carbonic Bachu Formation bearing identification features including an existance of collapsed breccias and subsurface stream,differential properties of Sr/Ba ratio filled in caves,which was obtained through the latest research on sedimentology,seismology,geochemistry.The karst paleotopography can be divided into four units: karst highland,Ⅰ-and Ⅱ-karst slope,karst basin,according to which the study area grew in Ⅱ-karst slope.As for the characteristics of pulse-type uplift in early Hercynian stage,three karst cycles occur in the investigation region,where Ⅱ-and Ⅲ-cave stratigraphy grew chiefly.The karst zone predominately covers beyond the pinch-out line of upper Ordovician Sangtamu Formation to the north in plane surface,while it occurs in pure carbonate of mid-lower Ordovician vertically.Karst within this stage was not only controlled by paleotopography and fracture essentially but was the key to the fracture and corrosive caves formation affecting reservoir capability of accumulation and permeability.Finally,an engendering model during early Hercynian stage can be established which can be divided into three phases in terms of developing process: rapidly uplifting and eroding phase,three scene uplifting phase and declining phase.更多还原