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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。
The middle-period paleo-karstification of the Middle Caledonian movement in the northern Tazhong area started to develop after the deposition of the Upper Ordovician Tumen Shike Group and ended after the deposition of the fourth member of the Lianglitage Formation in the Upper Ordovician. The paleokarst lasted for a long time and was rich in karst features Obviously, it can be comprehensively identified by features such as geology, drilling, conventional logging, imaging logging and earthquakes. The paleokarst vertical structure can be divided into surface karst zone, vertical diafiltration zone, runoff karst zone and deep slow flow zone from top to bottom. The runoff karst zone can be further divided into upper and lower subzone and transition zone. With the reduction of paleogeomorphology, the upper karst tends to be thinned or even undeveloped. The reservoir performance of the karst cave system formed by paleokarst is controlled by paleogeomorphology and sea level changes. Karst slopes are the favorable exploration zones, and the runoff karst zone and epikarst zone have the best reservoir performance vertically. Therefore, The Ordovician Yingshan Formation has great exploration potential.