济阳坳陷断裂演化与油气富集规律

Relationship between faults evolution and hydrocarbon enrichment in Jiyang depression

关键词:  济阳坳陷  郯庐断裂带  兰聊断裂带  “脉动式”伸展  走滑运动

Key words:  Jiyang depression  Tan-Lu faults belt  Lan-Liao faults belt  pulsative extension  strike-slip movement

摘要:

通过区域应力场特征、区域地震剖面和钻井等资料分析,并依据区域应力场控制下不同走向断裂的演化特征、叠合效应及其约束下不同凹陷成藏要素的差异,对济阳坳陷不同凹陷的油气富集规律进行研究。结果表明:济阳坳陷在印支期板块拼合作用影响下形成“多米诺骨牌式”有序逆冲褶皱,燕山期在东侧的郯庐断裂带和西侧的兰聊断裂带左旋走滑运动及燕山-喜山期右旋走滑运动控制下,相继发生了“多米诺骨牌式”有序构造反转和北东向“帚状”走滑运动,依次形成北西向、北东向和北北东向断裂并相互叠加;不同断裂叠加效应下,各凹陷具有“脉动式”伸展过程,伸展率的差异控制了不同凹陷的成藏要素;济阳坳陷自南西向北东主要含油层系具有古近系至新近系逐渐上移的规律。

Abstract:

By analyzing the regional stress, seismic profile and drilling data,the hydrocarbon distribution in different sags of Jiyang depression was studied based on evolution characteristics and superimposition of different trend faults controlled by regional stress,as well as the analysis of variance of accumulation elements. The results show that the Domino style orderly thrust folds are formed with the tectonic plates mergers in the period of Indosinian tectonic movement. The Domino type orderly structural inversion occurs under the control of sinistral strike-slip stress in Tan-Lu faults zone in the east and in Lan-Liao faults zone in the west in the period of Yanshan tectonic movement. The NE "broom style" strike-slip movement occurs under the control of dextral strike-slip stress in the period of Yanshan-Himalayan tectonic movement. Therefore, NW, NE and NNE faults are orderly formed and superimposed. Controlled by the superposition of different faults, the sags are pulsative extension. The stretching rate controls the accumulation elements in different sag. The main oil-bearing stratum gradually becomes newer from Paleogene to Neogene in the southwest-northeast area.