At present, fluvial reservoirs have held sway over the reserves and production of the Bohai Bay Oilfield, and a relatively mature technical system for describing fluvial reservoirs has been established through development and production practices. With the increasing level of exploration and development in the Bohai Bay Oilfield and the deepening understanding of geology, reservoirs deposited in the river-lake interplay environment have gradually emerged as new types of oil reservoirs and development targets. In recent years, the Bohai Bay Oilfield has successively discovered several large to medium-sized river-lake interplay oilfields, characterized by the widespread development of Large composite sand body bodies. Within these compound sand bodies, river channels are densely distributed, with unclear individual channel responses, complex interactions between channels, and strong lateral heterogeneity in reservoir distribution. The intricate connectivity within the sand bodies and the presence of a multi-fluid system bring numerous risks to field development. With no prior experience in developing similar oilfields in the Bohai Bay region, the existing mature techniques for describing fluvial reservoirs cannot be directly applied, severely impacting the precision of geological and reservoir understanding in these types of reservoirs.
Addressing the challenging issue of efficient and precise development of complex sand bodies in river-lake interplay environments, this study conducts frequency-division iterative inversion based on spectral inversion, innovatively introducing river-channel sensitive attributes into lowfrequency model construction to compensate for lateral low-frequency components. This approach allows for iterative inversion results to progressively increase in frequency under the constraint of river channel planes, enhancing the vertical identification accuracy and lateral continuity of riverbed sand bodies. By utilizing this method to finely describe single river channels within compound sand bodies, the distribution patterns and contact relationships of individual river channels are clarified, providing guidance for the rational optimization of injection-production well networks and the efficient implementation of horizontal wells in oilfields.
