东营凹陷弧形断裂坡折带系统及其对低位域砂体的控制

Arc-shaped Fault Break Slope System and Its Control on Low Stand Systems Sandbodies in Dongying Depression

东营凹陷的弧形断裂系统由三个环带组成,由于这三个环带中断裂的同沉积活动导致了同沉积构造坡折带的发育,并进而对沉降中心、生烃中心和砂体均产生了重要的控制作用。已发现的大型低位扇体沿环带分布,并受断裂坡折带的控制。因此,沿层序界面,从构造坡折带向凹陷中心方向是找寻大型低位扇储集体的主要区域。文章总结了陡坡断坡带砂砾岩扇体成藏模式和缓坡构造坡折带两种成藏模式。前者储集体主要由坡折带上广泛发育的低位砂岩复合体组成,其中的扇三角洲河口坝、水下分流河道砂体和浊积扇的扇中部分是最有利的油气储层;后者储集体主要由由下切水道充填砂岩体、水下扇、废弃型三角洲等砂体组成。这些砂体均是良好的油气储层,并具有相似的成藏动力学过程。

Arc shaped fault system of Dongying depression is composed of 3 circle belts. Syndepositional faulting in these circle belts caused the development of syndeposotional fault break slope, which further controlled the distribution of subsidence centers, hydrocarbon generating center and sand bodies. Big low stand fan sand bodies that have been found distribute along the circle belts and were controlled by fault break slopes. Thus, important direction of finding new low stand reservoirs should be from fault break slope to sag depression along sequence boundary. Moreover, based on the analysis of hydrocarbon generating dynamics, migration systems and relationship between reservoirs and effective hydrocarbon rocks, two kinds of hydrocarbon accumulation models have been put forward in this paper. The low stand fans in fault break mainly are almost all favorable reservoirs for oil and gas, and show similar dynamic progress of hydrocarbon accumulation.