【摘要】 塔中地区北部斜坡带加里东运动中期古岩溶在上奥陶统吐木休克组沉积后开始发育,至上奥陶统良里塔格组良四段沉积后结束,古岩溶作用时间长,岩溶特征丰富而明显,可通过地质、钻井、常规测井、成像测井和地震等特征综合识别。古岩溶垂向结构自上而下可划分为表层岩溶带、垂向渗滤带、径流岩溶带和深部缓流带,其中径流岩溶带可进一步分为上、下两个亚带及过渡带。随着古地貌地势的降低,上部的岩溶带有减薄甚至不发育的趋势。古岩溶形成的缝洞体系的储集性能受古地貌及海平面变化控制,岩溶斜坡为有利勘探区带,垂向上以径流岩溶带和表层岩溶带储集性能最好,因而研究区下-中奥陶统鹰山组勘探潜力巨大。更多还原

【Abstract】 Starting development from Tumuxiuke formation to the end of Lianglitag No.4 member deposition of the Upper Ordovician in slope of northern Tazhong area,the paleo-karst process is so long and its feature is so abundant and obvious that can be comprehensively identified by the characteristics of geology,drilling,conventional logging,imaging logging and seismic data processing.The vertical structure of paleo-karst can be divided into surfacial karst zone,vertical percolation zone,radial flow karst zone and deep tranquil flow zone from the top to the bottom,among which the deep tranquil flow zone can be further divided into upper and lower subzones and one transitional zone.With the lowering of paleo relief,the upper karst zone trends to thinning and even undevelopment.Thus the quality of fractured-vuggy reservoir formed by the paleo-karst is controlled by paleo relief and sea level changes.The study suggests that the karst slope is favorable prospecting area,the radial flow karst zone and surfacial karst zone are of best reservoir quality,vertically,and the greatiest potential for petroleum exploration is the Yingshan formation of Lower-Middle Ordovician in the studied area.更多还原