松辽盆地葡西地区葡萄花油层断层垂向封闭性研究

在对松辽盆地葡萄花油层断层特征及构造发育史研究的基础上,计算了控制葡西地区断层垂向封闭性的断层带泥质含量和断面压力参数,评价了区内7条主要断层在姚家组沉积末、嫩二段沉积末、嫩三段沉积末以及现今4个时期对葡萄花油层的垂向封闭性,并简要地探讨了断层封闭性与油气成藏之间的关系。研究结果表明:在姚家组沉积末,断层垂向呈开启状态;在嫩二段沉积末,4号和5号断层呈开启状态,其余断层呈封闭状态;在嫩三段沉积末至现今,断层垂向均呈封闭状态。整体而言,葡西地区北北西向断层封闭性好,有利于封闭油气在葡萄花油层成藏;北北东向断层持续活动时间较长,是青山口组源岩油气的运移通道。

Research on Vertical Sealing Properties of Faults of Putaohua Reservoir in West Putaohua Oilfield of Songliao Basin

On the basis of studying fault characteristics and structure development history of Putaohua reservoir in west Putaohua Oilfield and calculating the content of shale in fault-plane zone and the parameters of normal stress on fault surface,which controls the vertical sealing capability,this paper evaluated the vertical sealing properties of 7 major faults in four periods and briefly discussed the relation between fault sealing and its evolution history and hydrocarbon migration,accumulation and reservoir formation.Four periods including the end of the Yaojia Formation deposition,the end of the second member of Nenjiang Formation deposition,the end of the third member of Nenjiang Formation deposition and the present were investigated.The results showed that:(1)Faults had poor vertical sealing capability at the end of the Yaojia Formation deposition;(2)The vertical sealing capabilities of No.4 and No.5 faults remained relatively poor but others were good at the end of the second member of Nenjiang Formation deposition;(3)Faults had strong vertical sealing properties from the the end of the third member of Nenjiang Formation deposition to the present.Generally,the NNW-trending faults had nice vertical sealing properties and were favorable for oil-gas accumulation in Putaohua reservoir;And the NNE-trending faults had a comparatively long open period and could act as main hydrocarbon migration passages for the source rock in Qingshankou Formation.