塔中地区奥陶系碳酸盐岩储层特征及其油气意义

为了探明塔中地区奥陶系碳酸盐岩储层特征及其油气意义 ,根据勘探资料分析 ,奥陶纪时期 ,发育了下奥陶统以白云岩为主 ,上奥陶统以灰岩为主的巨厚碳酸盐岩沉积 ;同时 ,在中、上奥陶统与塔里木盆地中部地区下奥陶统之间和上奥陶统顶部发育两个不整合面 .在构造、沉积和后生改造的共同作用下 ,碳酸盐岩发育有下奥陶统白云岩层系和中、上奥陶统灰岩层系两套储集岩系 ,以及白云岩内幕型、风化壳岩溶型、构造裂缝型、沉积相带控制型和深部流体改造型 5种主要储集体类型 .根据储层的发育与分布特征 ,提出今后塔中地区应重点加强塔中北斜坡、塔中西部和西北倾没端区域上的油气勘探 ;在纵向上 ,应加强对深部下奥陶统以白云岩内幕型储集体为储层的碳酸盐岩油气勘探工作

Features and petroleum significance of Ordovician carbonate reservoir in Tazhong area,Talimu Basin

The analysis of exploration data shows that under the control of the tectonic evolution of Talimu Basin, mega-thickness carbonate deposit develops in Tazhong area during Ordovician period, which mainly consists of lower Ordovician dolomite series and middle—upper Ordovician limestone series; two unconformity surfaces develop in between lower Ordovician and middle—upper Ordovician and at the top of upper Ordovician separately. Under the joint action of structures, sedimentation and epigenetic transformation, two sets of carbonate reservoir rock systems develop in this area, they are lower Ordovician dolomite reservoir rock system and middle—upper Ordovician limestone reservoir rock system separately, and five types of carbonate reservoir bodies, they are inside dolomite type, weathering crust karst type, tectonic fracture type, sedimentary facies belt controlling type and deep fluid transforming type. According to the development and the distribution of reservoir rocks, it is put forward that, laterally, the oil and gas exploration activities should be enhanced in the northern slope, the west area and the northwestern pitching end of Tazhong area, and vertically, the emphasis of exploration should be on deep lower Ordovician dolomite reservoir series.