Distribution of remaining oil based on fine 3-D geological modelling and numerical reservoir simulation: a case of the northern block in Xingshugang Oilfield, China

As the Xingshugang Oilfield is in the late stage of development, a conventional geological model could not meet the needs of further enhancing oil recovery, and the establishment of a fine 3-D geological model, namely the 3-D reservoir architecture model, is urgently required. The 3-D reservoir architecture model has a strong advantage in the detailed characterization of the distribution of various architectural elements and flow baffles and barriers in 3-D space. Based on the abundant data from close well spacing, in combination with the understanding of sedimentary facies and reservoir architecture, this study builds the 3-D reservoir architecture model to show the spatial distribution of different architectural elements and intercalations (mud drapes) under the control of third-, fourth- and fifth-order bounding surfaces. The study then establishes the property model under the control of sedimentary facies (architectural elements). Subsequently, based on the fine 3-D geological model, the distribution of remaining oil is obtained after the numerical reservoir simulation. The remaining oil primarily lies in the port of channel bifurcation, the parts blocked by intercalations and abandoned channels, and the edges of different facies. This observation provides a theoretical basis for further development and adjustment.