Nan Zhang

To address the problems of rapid water cut increases and severe interlayer interference in offshore composite rhythmic edge-water reservoirs, this paper aims to reveal the three-dimensional spatiotemporal evolution laws of water-flooding fronts under complex heterogeneous conditions. A systematic study was carried out using a combination of three-dimensional large-scale physical simulation, mathematical derivation, and orthogonal numerical simulation. The results indicate that under composite rhythmic conditions, the dynamic interplay between the interlayer permeability differential and gravity segregation exacerbates bottom-water channeling, while a bottom low-permeability zone and a large formation dip angle effectively inhibit water underride. Crude oil viscosity and liquid production rate are the core factors affecting the recovery factor. Furthermore, the constructed water breakthrough time prediction model, which considers additional gravity potential energy, demonstrates a stable calculation error within 4.6%. The study confirms that promoting the longitudinally balanced advancement of multilayer oil–water fronts is the key to improving macroscopic sweep efficiency, and the optimized balanced sweep mode improves the ultimate recovery factor by up to 8.57% compared to the extreme channeling mode, providing scientific guidance for water control well selection and the optimization of liquid production schedules in offshore edge-water reservoirs.

T-junctions have been applied in water-control structures. A comprehensive understanding of shunt characteristics can contribute to the optimal design of T-junctions. In this work, we seek to understand the shunt ratio of fluids with different viscosities in a T-junction and to achieve a greater shunt ratio. The computational fluid dynamics (CFD) approach is applied to study the influence of the properties, such as the fluid viscosity, the branch angle, the channel shape, and the flow rate, on the shunt ratio in a T-junction. The viscosity of oil can be divided into three intervals, and the optimal angles of the T-junction are different in each interval. For the fluid viscosity in the 1–20 cP range, the optimal branch angle is in the 45–60 deg range. For the fluid viscosity in the 20–65 cP range, the branch angle should be designed to be 45 deg. For the viscosity greater than 65 cP, the branch angle should be designed to be 75 deg. The appearance of the eddy and secondary flow will reduce the flow. The secondary flow and eddy intensity on the branch increase with increasing angle. The secondary flow intensity of the main channel decreases gradually with the increase in the angle. This study provides an important guidance for the design of automatic water control valve tools.

At present, AICD completion is an effective way to slow down the bottom water cone. Effective extension of the period without water production. According on the basis of investigating the AICD both at home and abroad, this paper designed a new type of AICD, and with the help of fluid numerical simulation software, the internal flow field was analysed, and its structure is optimized. The simulation results show that the tool can restrict the flow of water well, and the flow of oil is less.