试论泌阳断陷陆相层序水进体系域的油气地质意义

The transgressive systems tract of the continental sequences in the Biyang fault depression: oil and gas geological significance

关键词:  生储盖组合  储集性能  扇三角洲  水进体系域  陆相层序  泌阳断陷

Key words:  source-reservoir-seal association  reservoir quality  fan delta  transgressive systems tract  continental sequence  Biyang fault depression

摘要:

泌阳断陷湖盆陆相层序水进体系域以退积型扇三角洲为其沉积主体,靠近构造枢纽的陡坡带边缘,冲积扇相域越来越窄,而向盆内则由滨浅湖逐渐过渡为半深湖。断陷湖盆水体属水进型湖泊。水进体系域中油气潜在储集体包括冲积扇的辫状河道砂体及扇三角洲的分流河道、水下分流河道、河口砂坝和前缘席状砂体。但由于它们形成的古环境及物理化学条件的不同,其砂砾岩中所含粘土矿物类型及数量亦有显著差异,对其储集性能将产生不同程度的影响。

Abstract:

The transgressive systems tract of the continental sepquences in the Biyang fault depression as a lacustrine basin is dominated by a retrogradational fan delta. The fluvial fan facies area becomes narrower and narrower at the edges of the slope zone close to the structural hinges. There are gradations from a littoral-shallow lake basinwards into a bathyal lake.The hydrocarbon reservoirs in the transgressive systems tract consist mainly of braided channel sandstone bodies in the alluvial fan facies,distributary channel,subaqueous distributary channel,chnnel mouth bar,and frontal sheet sandstone bodies in the fan delta facies. Since all of them were laid down in different depositional environments and physical and chemical conditions,the types and contents of the clay minerals from the sandstones and conglomerates may differ greatly and have exerted an important effect on the reservoir quality of the sandstones in the transgressive systems tract.