黄河口凹陷南部斜坡带低阻油层成因分析

近几年在黄河口凹陷南部缓坡带馆陶组获得了一系列的油层发现,其中含有大量的低电阻率油层,且存在高产能的低电阻率油层,具有一定的勘探潜力,由于低阻油层与水层电阻率相当,给测井评价带来了较大的难度。综合岩心、薄片等资料,从粒度、泥质含量及黏土矿物、孔隙结构、束缚水饱和度、导电矿物等5个方面对该区馆陶组低阻油层微观成因机理进行了系统的研究。通过低阻储层段与正常储层段多方面的对比,得出研究区岩性细、泥质含量高、孔隙结构复杂,高束缚水饱和度是影响该区储层低阻的重要因素。在此基础上,探讨了低阻的宏观地质成因,认为该区馆陶组低阻油层的形成在地质上受研究区内沉积背景及成藏动力的控制。

Causes analysis of low resistivity oil reservoirs in southern slope zone of Yellow River Mouth sag

A series of oil reservoirs have been discovered in Guantao formation of southern gentle slope in Yellow River Mouth sag in recent years,which contains a large number of low resistivity reservoirs,and there are also low resistivity reservoirs with high capacity and good exploration potential.As the resistivity of oil reservoirs is similar to those of water formation,there will be greater difficulty in logging evaluation.In combination with cores and thin sections,from particle sizes,clay content and clay minerals,pore structure,bound water saturation,and conductive minerals these five aspects,a systematic study on genetic microscopic mechanism of low resistivity reservoirs has been carried out.Through comparison between low- resistivity reservoir interval and normal reservoir interval,the causes such as fine lithology,high clay content,complex pore structure and high irreducible water saturation have been found out.On the basis of this,macro-low resistivity geological origin of low resistivity has been discussed and the results show the low resistivity oil reservoir of Guantao formation are geologically controlled by depositional background and reservoirforming dynamic.