Production and injection in long reach horizontal wells pose several challenges in production optimization, flow assurance and reservoir management. Horizontal wells are known to be superior to vertical wells in terms of productivity, however, they are also susceptible to early water and/or gas cut production due to the heel-toe effect and/or permeability contrasts. Uniform distribution of water injection into all zones can also be a challenge in case of high-permeability streaks and fractures. To negate some of the adverse reservoir properties and to control the flow profile of production and injection fluids, downhole flow control devices are increasingly in use and beneficial in regulating flow, improved overall reservoir sweep, improved productivity from the tail section of the well and reduced water coning or gas cusping. Wellbore hydraulics for a long reach well completed with downhole valves have great influence on the reservoir performance and recovery in the long run. This paper presents a discussion aimed at better understanding of the critical challenges that long reach horizontal wells are prone to in terms of completion, as well as the developments so-far that have been applied to capture the physics across the long horizontal section. Three case studies are also discussed with some details emphasizing practical experiences of such wells.

 

Key words: Downhole flow controllers, horizontal wells, inflow control devices (ICD), internal control valves (ICV), production enhancement.