Numerical Assessment of the Impact of Sand Control Techniques on Production in a Vertical Well

This study considers a vertical well producing initially without sand control technique in sandstone reservoir in the Niger Delta region. The study uses the data and information of two wells and applied PROSPER to numerically quantify the impact of the extra flow restriction caused by the gravel pack and slotted liner systems respectively. Well model was constructed and several simulations runs performed on key influencing production parameters (production rates, superficial velocities, skin development, pressure losses) and sand control design variables (gravel pack length, gravel pack permeability, slot height and slot width). The study involved two different sand control for two wells (Well X1 and Well X2) which were similarly completed and subjected to the same reservoir and operational conditions. The influence of sand control parameters on the vertical lift performance and inflow performance characteristics of the wells were analyzed at varying first node pressure (500psig – 1400psig). The solution node was set at bottom hole to enable proper diagnosis of the influence of the sand control options on the VLP/IPR relationships. At base case scenario, the gravel pack oil and gas production rates were 8010.0STB/day (ORAT) and 6.008MSCF/day (GRAT) at a flowing bottomhole pressure of 4231.38Psig while the slotted liner was 8010.0STB/day (ORAT) and 6.008MSCF/day (GRAT) at a flowing bottomhole pressure of 4231.38Psig at a flowing bottomhole pressure of 4231.38Psig of 3902.46Psig. The resulting skin due to sand control were 0.0070375 and 0.18 respectively. Result shows that Slotted Liners provides better sand control than gravel packs but causes more pressure drop in the system due to sand control method. Furthermore, Gravel pack permeability and length and slot dimensions have most remarkable influence on the pressure drop due to sand control and can play a crucial role in the choice and design of any gravel pack system and slotted liners respectively. It’s advisable or better that Gravel pack permeability should not exceed 500000md for optimal performance as a sand control device. The work recommends the use of higher slot width to slot height for more efficient production using slotted liners while smaller gravel permeability could be preferred for better sand control with gravel pack systems.