| Block of Mao 10 and Mao 11 in Daqing Toutai oilfield have entered the stage of late development,there are still a considerable amount of remaining oil in the underground reservoir.Mainly controlled by reservoir architecture,the distribution feature of remaining oil shows that it generally distributed with accumulation in certain areas.This paper uses the research thought of the method of scale analysis,and put forward an analysis method of reservoir architecture in meandering river and meander distributary channel,and then the distribution mode of remaining oil which is controlled by reservoir architecture of different size has been concluded,which provide a powerful geological basis for further development.According to the well logging data,core data and physical data,the distribution and physical characteristic of compound sand body has carried on the comprehensive understanding.Combining the theory of fine stratigraphic contrast and depositional model,using the sedimentary intermittent to split face compound sand body,the fine division and layer contrast of 34 sedimentary units of 566 wells in Fuyu reservoir have been completed.Based on fine stratigraphic division and correlation,using the thickness of sand,sand ratio,the dissection method of dense well spacing area,the provenance of study area is confirmed to southwest.Combined with the observation of core,2 types of facies,3 types of subfacies,22 types of microfacies have been recognized,and then the correlative logging facies pattern have been established.And according to the size of river of different sedimentary subfacies,different depositional time unit are classified,which provide a deep understanding to the reservoir.Based on characterization of sedimentary microfacies of different sedimentary time unit,summarizes the abandoned channel,the phase change near the river,different height of river sand body,and the different thickness of channel sand body and so on four ways to determine the boundary of single channel.On the basis of the single river,point bar has been recognized.Combined with field outcrop,core data,the empirical formula,the parameters of muddy lateral accretion sandwich in point bar has been calculated.The dip of muddy lateral accretion sandwich is between 3°and 11°.The inclination of muddy lateral accretion sandwich is always from convex-bank to concave-bank which is perpendicular to the abandoned channel tangent point tangent direction.The size of muddy lateral accretion sandwich is between 10 m and 120 m.On the basis of analysis of reservoir architecture,the waterflooded interpretation chart has been established,which provides a comprehensive understanding for the distribution of remaining oil.Combined reservoir architecture and remaining oil,three kinds of remaining oil which controlled by reservoir architecture of compound sand body has been concluded.They respectively are firstly,the remaining oil which formed by shelter of the causes of the interface between single channel in compound sand body and planar phase change;Secondly,the remaining oil which formed by positive rhythm in single channel and the shelter of abandoned river;Thirdly,the remaining oil formed by the shelter of muddy lateral accretion sandwich in point bar. |
