千米桥潜山凝析油气藏奥陶系碳酸盐岩储层特征及演化

CHARACTERISTICS AND EVOLUTION OF ORDOVICIAN CARBONATE ROCK BED OF OIL-GAS CONDENSATE RESERVOIR IN QIANMIQIAO BURIED HILL

千米桥潜山奥陶系储层经历了两次裸露岩溶及古近纪后的深埋藏成岩作用。其中印支—早燕山期裸露岩溶属溶丘(梁)洼地型岩溶发育模式,是储集空间形成的重要时期。6期胶结事件的详细解剖表明,喜马拉雅期深埋藏岩溶主要与腐蚀性热流体作用有关,是形成现今储层孔隙系统的最关键时期。局限的热液岩溶和裸露的背斜轴部之下的混合带对千米桥潜山奥陶系孔隙分布具有重要控制作用,预期在印支期挤压逆冲作用形成的背斜轴部,特别是潜山内幕背斜形态与潜山顶面形态相互协调的区域,应是储层发育最好的部位。

Ordovician carbonate rock bed of Ordovician reservoir in Qianmiqiao buried hill experienced two times of karst exposure and the post plaeogene deep-buried diagenesis.The first is the depression karst development pattern from dissolution of karst hill during Indo-Chinese epoch which is the key period for forming space of the reservoir.Analysis of six cementing events indicates that the deeply buried karst during Himalayan epoch is related to corrosive hydrothermal fluid and is the key period for forming porous system of the present reservoir.The limited hydrothermal karst and mixed zone beneath the anticline axis controls the porosity distribution of Ordovician System and it is anticipated that surroundings of the axis of fold formed by compressional reverse orverthrusting during Indo-Chinese epoch and the coordinated area of morphology of anticline in the screen of buried hill and that of top surface morphology is the best position for development of the reservoir.