New Inflow Control Device Reduces Fluid Viscosity Sensitivity and Maintains Erosion Resistance

摘要

In long horizontal wells, production rate is typically higher at the heel of the well than at the toe. The resulting imbalanced production profile may cause early water or gas breakthrough into the wellbore. Once coning occurs, well production may be severely decreased due to limited flow contribution from the toe. To eliminate this imbalance, inflow control devices (ICDs) are placed in each screen joint to balance the production influx profile across the entire lateral length and to compensate for permeability variation. Pressure drop in an ICD is created through either restriction or friction mechanisms. Restriction mechanisms rely on a contraction of the fluid flow path to generate an instantaneous pressure drop, resulting in higher velocities, and are thus more prone to long-term erosion damage as well as plugging during mud flowback. A restriction device, however, is less sensitive to viscosity properties of the fluid. A frictional device, which creates a pressure drop over a distributed length, is less likely to erode due to lower fluid velocities, but is more sensitive to viscosity changes. Viscosity insensitivity is desired to minimize preferential water flow whenever water breaks through into the well. This paper will detail the development of a new hybrid design concept that uses the best features of the restricting and friction designs, while minimizing the less desirable characteristics. Because these ICDs are permanent downhole components, their long-term reliability is imperative, and these new developments will improve their resistance to erosion and their ability to effectively balance inflow. Conceptual fluid dynamics analysis was used extensively to characterize the new design, along with actual full-scale flow testing.