I Increasing natural gas demand in Indonesia has driven many operators todevelop potential gas field assets, whether offshore or onshore, across Indonesia.One such field is IO which is located offshore East Java in a tectonically active areaand part of the AIO complex. The field is composed of carbonate rock which isglobigerinid in nature, with the presence of different facies such as packstone,wackstone and grainstone, of which the latter has the best permeability. Anextensive geomechanical study was conducted and one conclusion was that solidsand fines production are likely to happen from the carbonates in this field. Toprevent minimize the risk of solids production, an open-hole gravel pack (OHGP)system was designed and deployed.Horizontal OHGP involving screens equipped with shunt tubes for alternatepacking are commonly deployed in unconsolidated sandstone formations aroundthe world. Using filter cake breakers, during or after OHGP placement, is regularlyincluded as part of these treatments. The BC is a carbonate field, besides the lowfrac gradient and the naturally fissured characteristics associated to the rock whichmakes it prone to high leak-off, the completion strategy required a special designedfilter cake breaker inert to the formation and capable of helping to minimize the liftoffpressure; the challenge required a different approach.The successful completion of these wells required the use of state-of-the artgravel pack placement simulator, special analysis of Bottom Hole data during gravel pack placement and customized gravel pack fluid, capable of transportingproppant and clean the filter cake afterwards.Three horizontal wells with 9 5/8-inch casing and an average of 8.6-inchopen-hole diameter were drilled and successfully completed. Gravel pack placement interpretation using bottom-hole gauge data shows full annular packingfor all OHGP cases. After completion, wells were started smoothly with no productivity drawbacks and no solids production observed.This paper highlights key technical challenges and risks encountered during the preparation, design, execution and evaluation stages of this operation anddiscusses how these challenges were overcome and the risks mitigated. Finally, the lessons learned and their implementation towards the improvement and optimization of future operations are discussed.