东营凹陷永安镇油田沙三段“槽谷”砂体发育规律研究

Distribution of Trough Valley Sand Body in the Third Member of Shahejie Formation in Yonganzhen Oilfield,Dongying Sag

针对砂岩、砾岩岩性油气藏发育和分布规律这一难题,以东营凹陷永安镇油田沙三段"槽谷"砂体为例,对"槽谷"砂体进行了研究。"槽谷"砂体是主要以扇三角洲前缘砂体为主的1套在断陷湖盆陡坡带发育的一种砂体。在地震剖面上,砂体在横向上超覆尖灭在下伏沉积物之上,电性特征明显,SP曲线上砂体由下而上为齿化漏斗形、多个高幅齿化箱形、齿化箱形与齿化钟形。"槽谷"砂体储层不管在横向上还是在纵向上都有较大的变化:纵向上,砂体的厚度变化大;横向上,砂体的连续性很差。其成因为沉积物向盆地充填过程中,遇到北西西向延伸的断槽,沿着这些断槽向西进入湖盆,并在断槽内形成扇三角洲前缘沉积。

In this paper,we researched the trough valley sand body in sand and glutenite reservoir.The trough valley sand body was composed of front sand body of fan-delta in the fault depression.On the seismic profile,the sand body was pinched out at sedimentary body underlying.The electric feature of the sand body was obvious.From bottom to top,the SP curve of sand body was tooth-infundibular form,high amplitude tooth-box form,and tooth-campaniform,respectively.The reservoir of trough valley sand body was various laterally and vertically.The thickness of sand body was vertically changed,in contrast that the continuity was laterally bad.Because the sediments along the trough fault came into the fault depression and formed the front intrafacies of the fan-delta when they encountered the NW extended trough.