Integrated Technology of Water Control and Viscosity Reduction for Horizontal Wells in Heavy Oil Reservoirs: Composite System of Viscosity Reduction Agent/Nitrogen

Horizontal wells are an important method to enhance oil recovery in bottom-water heavy oil reservoirs, but the contact area between horizontal Wells and reservoirs is large, and the water cone is usually larger than that of vertical Wells in late development, which increases the difficulty of management. In view of this, the flexible water control system with nitrogen and viscosity reducer is studied in this paper. Through a series of two-dimensional quantitative experiments and visualization experiments, the optimal combination and dosage of the composite system were determined, and the mechanism of water control was revealed. The results show that the optimal design is to inject VR first and then N2. The optimal dosage of VR and N2 is 0.1 PV and 0.3 PV of the water cone pore volume. As a solvent, VR enters the reservoir through osmosis to reduce viscosity of heavy oil and eliminate water cone. N2 strengthens this osmosis. This technology has achieved a good effect on water control and oil increase in field application. This study provides theoretical guidance for the efficient development of horizontal Wells in the same type of heavy oil reservoirs.