湘西澧五井T1d-P1q沉积及成油期探讨

澧五井位于扬了地台桑植石门复向斜东部.通过对澧五井成岩期后变化的研究和油期显示的综合分析,笔者认为:澧五井T₁d-p₁q各组的油主要来源于自层和邻近层.它们有二次生油期,第一次生油期为巴东组沉积期,此时T-P地层中有机质向石油演化还未达到最高峰,有的刚开始进入生油门限,由于印支运动二幕使地壳强烈抬升、剥蚀,地温降低,有机质停止向石油转化.第二期为燕山运动热液活动期,澧五井P-T进油期为生油期和稍后.最后指出:中扬子T-P油气的有利地区应为上覆具有较大的中新代盆地的地区. 

THE TIME OF THE SEDIMENTATION AND THE OIL FORMATION OF T1b-P1q SEQUENCE OF Li No.5 WELL OF WESTERN HUNAN

Li No.5 Well is situated at the eastern part of Shangzhishimeng Syn clinorium of Yangtze Platform.Through the study of the diagenesis and epigenesis of Li No.5 Well and the comprehensive analysis of the oil/gas display,the authors think that the T₁d-P₁q oil of Li No.5 well is originated in situ.There were two oil generation stages in which the first stage is Badong sedimentary stage.At this time,the evolution of organic matter to generate oil in T-P strata has not reached its peak,and some organic matter just began on the threshold of oil generation.The two episodes in Indosinian movement brought the earth crust to be uplifted,eroded,geotemperature dropped,and the petroleum generation was stopped.The second stage is the thermal fluid activity in Yanshan movement.The reservoir in P-T₁ of Li No.5 Well was at oil generation stage or a little bit higher.Finally,this paper points out that the favourable area for T-P oil and gas of Mid-Yangtze should be the area which is overlaid with major Mesozoic-Cenozoic basins.