【摘要】 塔河油田奥陶系碳酸盐岩主要经历了加里东中期及海西早期岩溶作用。前人认为,桑塔木组泥岩隔水层控制了海西早期岩溶的分布范围:北部的桑塔木组缺失区是海西早期岩溶的发育区,并对先期的加里东中期岩溶产物加以全面改造;而南部的桑塔木组覆盖区则仅保留了加里东中期岩溶。通过岩石学、沉积学、地球化学及地震学等研究表明,海西早期岩溶可以在一定范围内突破桑塔木组的限制。桑塔木组的覆盖仅仅改变了海西早期岩溶作用的形式,即由裸露风化壳型岩溶转变为覆盖承压型岩溶。指出了与主体区相连的断裂带才是岩溶—缝洞型储层的发育区带,而孤立的、不与主体区相连的断裂带,则岩溶作用不发育。该岩溶作用的发现,对于在塔河油田南部、西部桑塔木组覆盖区寻找岩溶缝洞型储层发育带具有重要的指导意义。更多还原

【Abstract】 The Ordovician formations of Tahe Oilfield mainly undergo two karsts of mid-Caledonian and earlyHercynian.The predecessors considered that because of the thick aquifuge in Sangtamu Group(O3),the effectingrange of early-Hercynian karst was controlled by the edge line of the Sangtamu Group: The Northern part which lackNo.3 Abstract Vthe Sangtamu Group was the affecting area of early-Hercynian karst,while,the Southern part which was coveredby the Sangtamu Group was the the affecting area of only mid-Caledonian karst.Recent research shows that for thereason of its favourable factors,such as high-uplift amplitude of structure,long time exposure,highly developmentof fractures,fluent hydrodynamic etc,it is extremely beneficial to karst effections.On top of that,the early Hercyniankarstis able to break through the restriction of the Sangtamu aquifuge.The coverage of the Sangtamu group onlychanges the model of early-Hercynian karst:from crust karst to Covered-Pressurization karst.The discovery of thiskarst has a great guiding significance to the exploration for cavity-reservoirs in the southern and southwestern areas.It points out that,only the fault zones which are connected with the main region can be the favourable reservoirzones,otherwise,Reservoir would be less developed.更多还原