陆相裂陷盆地层序地层构成样式分析--以泌阳凹陷核三上段为例

层序地层源于被动大陆边缘盆地 ,如何将层序地层分析应用于陆相裂陷盆地是当前一个热点课题 ,近年来国内外对陆相裂陷盆地层序的研究取得了重要的成果。可容空间和沉积物供给沿着活动断层走向和倾向上的变化是控制陆相裂陷盆地层序发育样式的两个主要因素。在走向上 ,断块中部断层活动性最强 ,构造沉降最大 ,可容空间增加速率也最大 ,沉积物大多短源供给 ,以发育 型层序为主 ,向着断端 ,断层的活动性逐渐减弱 ,上盘下降和下盘上升速率相对减小 ,形成相对低地 ,是沉积物优先通过的场所 ,以 型层序发育为主。沿着倾向上 ,靠近断层的陡坡带断层活动性强 ,位移大 ,发育 型层序 ,向着远离正断层的缓坡带 ,构造活动性逐渐减弱 ,基底沉降减小 , 型层序样式发育。 型层序的下切谷和盆底扇以及斜坡扇是良好的储集体 ,具有良好的石油勘探前景

ANALYSIS OF THE SEQUENCE-STRATIGRAPHIC PATTERN OF CONTINENTAL RIFT BASIN--TAKING BIYANG DEPRESSION AS AN EXAMPLE

How the sequence-stratigraphy originated from the passive continental margin basin is applied to continental rift basin is a hot topic. Great progression has been made at home and abroad.Stratal patterns are greatly affected by local factors. Accommodation and sedimentary supply, are the two main factors that control the sequence styles. Subsidence varies along strike as well as along dip direction. Along strike, subsidence is maximal at the fault segment center, and newly added accommodation rate is maximal too, and Type Ⅱ sequence is developed at the fault center. Subsidence diminishes gradually from the fault segment center to the fault tip, and the newly added accommodation rate diminishes too. At the fault tip, Type Ⅰsequence is developed. In the dip direction, the tectonic activity of the steep slope zone near the master normal fault is energetic, and Type Ⅱ sequence is developed. The ramp zone far away from the master normal fault is gently effected by tectonism, and Type Ⅰ sequence is developed. The incised valley, floor fan and slops fan of Type Ⅰ sequence are of great importance in the oil and gas exploration and production.