碎屑岩中油气初次运移输导体系分类及特征

CLASSIFICATION AND CHARACTERISTICS OF HYDROCARBON PRIMARY MIGRATION AND TRANSPORT SYSTEM IN CLASTIC ROCKS

康德江

Kang Dejiang

中国石油天然气股份有限公司, 大庆油田有限责任公司, 勘探开发研究院, 黑龙江, 大庆, 163712

Research Institute of Petroleum Exploration and Development, Daqing Oil Field, CNPC, Daqing, Heilongjiang 163712, China

油气初次输导体系对于油气二次运移有着直接影响,甚至关系到最终油气藏规模。参照、类比烃类二次运移输导体系,从微观角度分析入手,基于不同油气微观输导通道的产生和组合形式,将碎屑岩中油气初次运移输导体系分为3类,即:正常型、次生型和终结型。正常型输导体系由烃源岩颗粒孔隙喉道和干酪根网络组成,以生烃膨胀而增大的毛细管力为主要动力,油气多以混溶相排出,少量为非混溶相;次生型输导体系由大量烃源岩次生微裂缝构成,源岩内部异常高压是非混溶相油气排替的主要动力,是排烃量最大、效率最高的输导体系类型;终结型输导体系由大量颗粒破裂缝和残存的少量微裂缝构成,剩余异常压力是驱动力,但效率很低,输导作用很小,直至消失。随着盆地中烃源岩埋藏史的变化,正常型与次生型输导体系之间可以在一定程度上相互转化,但终结型输导体系意味着初次运移通道的永久闭合和输导时期的完全终结。

Studies of hydrocarbon primary migration and transport system play an important role in secondary migration,even influencing final reservoir scale.According to researches of transport system during secondary migration,from microcosmic angle,based on generation and combination of different transport channels,the primary transport system in clastic rocks has been divided into 3 types: normal,secondary and terminative.The normal transport system is composed of pore throat and kerogen network.Hydrocarbon(most miscible phase and little immiscible phase) is expelled from source rock by capillary driving force formed from hydrocarbon bulging.The secondary transport system is formed by a large quantity of secondary microcracks.High excess pressure in source rocks is the main force for immiscible hydrocarbon expelling.In the secondary transport system,hydrocarbon expelling quantity is the largest and efficiency is the highest.The terminative system is composed of intergranular cracks and residual microcracks.The low excess pressure acts as the main force.The efficiency is low and the translocation is very weak,even down to vanish.Along with changes of burial history of source rocks in basins,the normal and the secondary transport system can transform reciprocally to certain extent,whereas the terminative system means the end of perpetual close of the primary transport canals and the complete finish of transport period.

国家“973”重点基础研究项目(2006CB202300)资助

https://doi.org/10.11781/sysydz200905455