Study on reservoir architecture characteristics and heterogeneity of the fan delta front

  The fan delta reservoir is developed in many basins in China widely, with which internal sand body structure is complex and strong heterogeneity. It is of great significance for the development of high water cut oilfield to determine the single sand-body superposed pattern and the development characteristics of inside the single sand-body in reservoir.Taking the upper Es3 in Gangzhong Oilfield, Huanghua Depression as an example, this paper studies the reservoir architecture characteristics and heterogeneity of the fan delta front.Most of the studies on reservoir architecture of fan-delta front at home and abroad focus on identification and quantitative characterization, but the characteristics and heterogeneity of architecture units under the constraints of a Multi-level interface are not explained.In view of the above problems, the author combined core, well logging and seismic data and took sedimentary genetic model as the constraint condition to quantitatively characterize the architecture interface in hierarchical order. Through the classification of architecture levels, the characteristics of composite genetic sand body and single genetic sand body and the study of heterogeneity, the reservoir architecture and heterogeneity of the upper submember of Sha3 in Gangzhong Oilfield were revealed. It provides a powerful theoretical basis for the subsequent exploitation of oil fields.  Specific steps include: (i) Combined with the sedimentary background of the fan delta front and the actual situation of the working area, the fine anatomy of the single genetic sand body and the composite genetic sand body is carried out by using the data of the dense well pattern, and the architecture model of the fan delta front in the study area is improved; (ii) Based on the identification marks of the architecture interface, the development characteristics of the architecture units constrained by the interface at all levels were defined, the overlapping mode inside the composite genetic sand body and the distribution characteristics of the sand body on the plane were established, and the characteristics of the single genetic sand body were described. The heterogeneity inside the architecture unit was analyzed according to the data, and finally the control effect of the reservoir heterogeneity was clarified by combining the sedimentary and tectonic processes; (iii) Through dynamic and static analysis, the remaining oil distribution model under the control of different reservoir architectures is established. The control effect of multi-stage architecture on remaining oil distribution is clarified, and the understanding of the control effect of reservoir architecture on remaining oil can provide reference for the exploitation of potential in the later stage of high water cut old oil field.