海平面波动中的岩溶响应——以塔里木盆地牙哈—英买力地区下古生界为例

Karst Development Respondence to Sea-Level Fluctuation: a Case from the Tarim Area in the Early Paleozoic

岩溶成因碳酸盐岩油气储层的展布预测,是全球石油地质家一直在探索的热点问题之一。下古生界岩溶型碳酸盐岩储层是盆地内极有潜力赋存大油气田的储集体。本文以岩溶类型研究为基础、以海平面波动史构建为切入点、以塔里木盆地下古生界为例,开展了海平面波动中的岩溶响应研究。分析表明,塔里木盆地早古生代海平面下降期均发育了准同生岩溶。准同生岩溶为埋藏岩溶和风华壳岩溶提供了良好的溶蚀介质输导孔隙。地球物理资料显示,塔北下奥陶统的两期风化壳岩溶叠加于先期的准同生岩溶作用之上。海平面波动史的重建及岩溶格架分析表明,塔里木地区早古生代海平面波动与岩溶发育呈现良好的耦合关系。海平面变化是控制塔里木盆地下古生界岩溶储层发育的一个重要的因素。

Karst carbonate reservoir development prediction draws much attention from petroleum geologists all over the world. Paleozoic karst carbonates is the most favorable for giant hydrocarbon pools exploration in the Tarim Basin, northwestern China. Based on karstification type and paleogeography evolution analyses, the paper investigates the karst development respondence to sea-level fluctuation taking the early Paleozoic Tarim Basin as an example. The analyses shows the penecontemporary karstification was developed during the regression stage in the Early Paleozoic Tarim Basin, which provides diagenetic fluid conduct layer for the subsequent buried and freshwater karstification. The seismic reflection profile shows there are two stages of freshwater karstification, which rebuilt upon the former penecontemporary karstification. Integrated research reveals that there was remarkable relationship between the karstification and the sea- level fluctuation in the Early Paleozoic Tarim Basin. The sea-level fluctuation was an important controlling factor for karst carbonate reservoir development in the Early Paleozoic Tarim Basin.