The Dongying Formation of LD Oilfield is a typical mid-deep oil reservoir in the Bohai Sea, with a burial depth below 2500 m. Due to poor seismic data quality and sparse offshore well pattern conditions, it is difficult to predict the range of high-quality reservoirs in areas with few wells, which poses a huge challenge to adjustment while drilling and rolling potential exploration during the development stage. A comprehensive analysis of the sedimentary characteristics and paleogeography of the Dongying Formation in the LD oilfield was carried out by utilizing core, logging, and seismic data, clarifying the changes in available space and source supply. The DIONIOS model was used to carry out forward simulation of sedimentation in the entire area. The results show that the Dongying Formation of the LD oilfield is a near source braided river delta sediment with a northwest oriented source. Vertically, it presents a shallow progradation feature of the water body, and the ancient topography is high in the southeast and low in the northwest. The sand control law of the ancient topography is obvious. The sand rich areas are mainly located in the A, B, and C well areas with low ancient topography. The D well area with high ancient topography has a small overall stratigraphic thickness and a thin interbedded structure of the reservoir. The research results effectively guide the deployment of well drilling in deep oil fields in offshore sparse well networks, pointing out the direction for further tapping potential, and have significant reference significance for efficient exploration and development of similar oil reservoirs.