塔里木盆地西克尔地区古岩溶储层露头表征

始新世末,喜马拉雅运动引起柯坪—巴楚地区广泛的水平挤压和构造抬升,导致奥陶系碳酸盐岩古岩溶出露地表,为古岩溶储层研究提供了很好的露头表征条件。本次研究选取塔里木盆地西克尔剖面为重点研究对象,探讨了古岩溶储层发育特征和演化模式。指出不同碳酸盐岩岩石结构对岩溶响应表现出明显差异:一间房组礁滩体岩溶储层小型溶孔、溶洞分布广泛;以泥晶灰岩和砂屑灰岩为主的鹰山组,岩溶作用形成裂缝为主控因素的大洞大缝型,非均质性很强的孔隙体系。研究区内同样发现了热液作用形成的深成溶洞,但数量和规模均较小。因此,古岩溶作用及伴生的溶洞系统是储层预测的关键。

Outcrop Based Reservoirs Characterization of Paleokarst

At the end of Eocene, Himalayan Movement leads to extensive lateral compression and vertical uplift in Keping-Bachu area which results exposure of Lower-Middle Ordovician paleokarst. This offers an excellent opportunity to take outcrop study of paleokarst reservoirs. To understand the characteristics and evolution process of paleokarst reservoirs formed in high-rainfall tropic climate, careful work was done at Xi Ke-er Outcrop. The study shows that carbonate with dissimilar rock texture response differently to resolution. Generally Yijianfang Formation, which consists of reel and beach, forms laminar reservoirs structure and vugs and small caves are well developed. However, Yingshan Formation has heterogenetic fracture-cavity reservoirs which controlled mainly by fractures. Hypogenic caves have also been found in region of interest, but theirs constructive roles is limited because of the amount and scale. Therefore the key factor of reservoir prediction is paleokarst and accompanying cave systems.