Gravel Pack Completion Using Autonomous Inflow Control Device Screens: A Solution to Water and Sand Control in Unconsolidated Sandstones Reservoirs

Abstract Several horizontal openhole wells completed with gravel pack completions offshore Gabon have experienced early water breakthrough, few months after completions. Curtailing water production is a key objective of the operators while it is important to effectively control sand production. A combination of standard screens (SS) and autonomous inflow control devices (AICD) screens were used along with gravel pack to address both the sand and water production concerns. Production modeling was carried out to establish the benefit of using AICDs in the field. Given the high viscosity contrast between the formation water and oil, the cyclonic Autonomous Inflow Control Device (type: AICD 2N) was selected for the application. The desired choking effect of AICD screens hinders the ability to completely pack the well, therefore detailed modeling was used as an attempt to identify the zones at which water was expected to breakthrough and more control was required Modeling results indicated that water was expected to breakthrough in the middle section of the drain. With this water production profile in mind, additional modeling was done using AICD screens solely across this section to control water breakthrough while OHGP SS were used in the other sections of the horizontal. With this optimized screen configuration, gravel pack modeling demonstrated that high pack efficiency was achievable. Two wells with 8.5-in. horizontal openhole sections were completed using a combination of OHGP SS and AICD screens with the alpha/beta gravel packing technique, resulting in complete packing using this optimized bottomhole assembly. The standard screen placed at the heel, in the casing section, provided a flow path enabling packing the AICD screen without substantial rise in the bottomhole pressure. To date, the two wells completed have been in production for more than one year and are yet to experience water breakthrough after completion. This paper will detail the challenges to design and successfully execute this operation.