塔河油田油气运移与聚集规律

通过对塔河油田油气地球化学特征、流体包裹体特征、储层沥青、储层自生粘土矿物、今古水动力场和今古流体势的分析以及油气输导条件等与油气运移与聚集关系的研究,认为塔河油田油气总体存在着“三期五次”油气充注期,即海西晚期(第一次)、印支—燕山期(第二次)和喜马拉雅期(第三、四、五次),其主成藏期为海西晚期和喜马拉雅晚期。海西晚期油气运移方向总体为由南向北,喜马拉雅期油气运移方向总体为由南向北、由东向西。研究认为,规模巨大的寒武—奥陶系主力烃源岩,为多期供烃、多期成藏提供了可靠的资源保障;处于古隆起、古斜坡有利区域构造位置,是油气长期运移的指向区;大型不整合面、岩溶输导网络、断裂带是塔河油田油气成藏的重要输导条件;多套储层、多套储盖组合、多种圈闭类型以及大型碳酸盐岩岩溶—缝洞型储集体发育是形成塔河大型复式油气田的重要条件;“早期成藏改造、晚期充注调整”是塔河油田奥陶系油藏重要的成藏机制,成藏封闭条件的形成与演化是塔河油气成藏的重要控制因素。 

OIL MIGRATION AND ACCUMULATION PATTERN IN THE TAHE OILFIELD

Based on study of geochemical characteristics,fluid inclusion characteristics,reservoir bitumen,reservoir autogenetic clay minerals,ancient and present tidal current fields,ancient and present fluid potentials,petroleum conduction condition related to petroleum migration and accumulation,petroleum charging process in the Tahe Oilfield can be divided into 3 stages and 5 times: late Hercynian(the 1st time),Indosinian-Yanshanian(the 2nd time),and Himalayan(the 3rd,4th and 5th time).The main accumulation stages are late Hercynian and Himalayan.During late Hercynian,petroleum migrates from south to north.During Himalayan,petroleum migrates from south to north and east to west.Huge Cambrian and Ordovician source rocks provide for multistage hydrocarbon charging and accumulation.Favorable tectonic locations on ancient uplifts and slopes are the target for petroleum migration.Large-scale unconformities,karst passage networks and fractures are channels for petroleum migration and accumulation.Sets of reservoirs,sets of reservoir and seal associations, types of traps and the generation of large-scale carbonate rock karst-fracture reservoirs are the key for the generation of large-scale composite oil-andgas field.Ordovician reservoir in the Tahe Oilfield is characterized by early accumulation transformation and late charging adjustment.Generation and evolution of sealing condition control hydrocarbon accumula-tion in the Tahe Oilfield.