塔里木盆地轮古地区奥陶系古岩溶作用及储层特征

Paleo-karstification and Reservoir Characterization of Ordovician Carbonates in the Lungu Area,Tarim Basin

通过古岩溶作用标志识别和成因分析,综合利用残余地层厚度法、地貌法和印模法等技术手段,对轮古地区奥陶系古岩溶地貌进行恢复,划分3个岩溶地貌单元和8类微地貌单元,并细分古岩溶地貌分区,对分区岩溶地貌及储层发育特征进行剖析。研究认为,不同岩溶带普遍发育裂缝和孔洞,但在不同地貌分区内储集类型具有明显的差异性。其中表层岩溶带的岩溶高地和斜坡主要发育裂缝孔洞型和裂缝型储层;垂直岩溶带裂缝、孔洞均发育;而径流岩溶带中的孔洞和洞穴较发育。

Based on the identification and genesis analysis of paleo- karstification, paleo-geomorphology of the Lungu area is reconstructed by using residual formation thickness method, geomorphologic method and impression method. Karst upland margin, karst slope, and karst valley of Ordovician carbonates in the Lungu area are marked and eight types of micro- geomorphology units are identified. The relationships between karst morphology and characteristics of carbonate reservoirs are studied in different subareas. The results show that all the karst zones develop fractures and vugs, but reservoir types are different in micro-geomorphology units. Karst upland and slope in the superficial karst zone mainly develop fracture-vug-type and fracture type reservoirs, the vertical karst zone develops fractures and vugs,and run-off karst zone is apt to develop vugs and caverns.